[ { "id": "01-system-context", "title": "LinkedIn — System Context", "layout": "context", "canvas": { "width": 1700 }, "system": { "label": "LinkedIn Platform", "sub": "Professional network", "icon": "di2_linkedin" }, "groups": [ { "side": "left", "title": "People", "nodes": [ { "id": "member", "label": "Member", "kind": "actor", "rel": "network · jobs", "dir": "in" }, { "id": "recruiter", "label": "Recruiter", "kind": "actor", "rel": "candidate search", "dir": "in" }, { "id": "employer", "label": "Employer admin", "kind": "actor", "rel": "jobs · company page", "dir": "in" }, { "id": "reviewer", "label": "Trust & Safety", "kind": "actor", "rel": "review queue", "dir": "in" } ] }, { "side": "top", "title": "Partners", "nodes": [ { "id": "sso", "label": "Enterprise SSO", "kind": "external", "rel": "SAML for seats", "dir": "in", "icon": "fa5_key" }, { "id": "ats", "label": "Applicant tracking", "kind": "external", "rel": "job feeds · hourly", "dir": "in", "kind2": "batch", "icon": "fa5_briefcase" }, { "id": "apps", "label": "Third-party apps", "kind": "external", "rel": "OAuth 2.0", "dir": "in", "icon": "fa5_handshake" } ] }, { "side": "right", "title": "Delivery and identity", "nodes": [ { "id": "push", "label": "APNs / FCM", "kind": "external", "rel": "push", "kind2": "async", "icon": "fa5_paper_plane" }, { "id": "email", "label": "Email delivery", "kind": "external", "rel": "SMTP", "kind2": "async", "icon": "fa5_envelope" }, { "id": "sms", "label": "SMS gateway", "kind": "external", "rel": "OTP codes", "icon": "fa5_comment_dots" }, { "id": "idp", "label": "Social identity", "kind": "external", "rel": "Google / Apple login", "icon": "fa5_user_check" } ] }, { "side": "bottom", "title": "Adjacent platforms", "nodes": [ { "id": "ads", "label": "Ads platform", "kind": "external", "rel": "sponsored slots", "icon": "fa5_ad" }, { "id": "pay", "label": "Payments", "kind": "external", "rel": "Premium", "icon": "fa5_credit_card" }, { "id": "rep", "label": "URL + file reputation", "kind": "external", "rel": "link and file scan", "icon": "fa5_shield_alt" } ] } ], "meta": { "v": "1.0", "owner": "Enterprise Architecture", "date": "2026-09" } }, { "id": "02-high-level-architecture", "title": "LinkedIn — High-Level Architecture", "layout": "flow", "chain": true, "stages": [ { "title": "Clients", "nodes": [ { "id": "h-web", "label": "Web client", "kind": "app", "sub": "SSR + SPA", "icon": "fa5_desktop" }, { "id": "h-mob", "label": "iOS / Android", "kind": "app", "sub": "native", "icon": "fa5_mobile_alt" }, { "id": "h-prt", "label": "Partner apps", "kind": "external", "sub": "OAuth 2.0", "icon": "fa5_handshake" } ] }, { "title": "Edge and API", "nodes": [ { "id": "h-afd", "label": "Azure Front Door", "kind": "integration", "sub": "global edge · TLS", "icon": "azure_frontdoor" }, { "id": "h-ats", "label": "Traffic tier", "kind": "integration", "sub": "Apache Traffic Server", "icon": "fa5_route" }, { "id": "h-api", "label": "API layer", "kind": "integration", "sub": "GraphQL over Rest.li", "icon": "fa5_plug" }, { "id": "h-id", "label": "Identity", "kind": "security", "sub": "sessions · MFA", "icon": "fa5_user_shield" } ] }, { "title": "Member services", "nodes": [ { "id": "h-prof", "label": "Profile", "kind": "app", "sub": "Espresso", "icon": "fa5_id_card" }, { "id": "h-graph", "label": "Social graph", "kind": "app", "sub": "LIquid", "icon": "fa5_project_diagram" }, { "id": "h-msg", "label": "Messaging", "kind": "app", "sub": "SSE delivery", "icon": "fa5_comments" } ] }, { "title": "Discovery services", "nodes": [ { "id": "h-feed", "label": "Feed", "kind": "app", "sub": "FollowFeed", "icon": "fa5_rss" }, { "id": "h-cont", "label": "Content", "kind": "app", "sub": "posts · comments", "icon": "fa5_newspaper" }, { "id": "h-srch", "label": "Search", "kind": "app", "sub": "Galene", "icon": "fa5_search" }, { "id": "h-jobs", "label": "Jobs", "kind": "app", "sub": "postings · applies", "icon": "fa5_briefcase" } ] }, { "title": "Event backbone", "nodes": [ { "id": "h-kafka", "label": "Kafka", "kind": "queue", "sub": "the central log", "icon": "kafka" }, { "id": "h-samza", "label": "Samza", "kind": "app", "sub": "nearline jobs", "icon": "fa5_stream" } ] }, { "title": "Asynchronous consumers", "nodes": [ { "id": "h-rec", "label": "Recommendations", "kind": "app", "sub": "Pro-ML · Venice", "icon": "fa5_brain" }, { "id": "h-ntf", "label": "Notifications", "kind": "app", "sub": "ATC", "icon": "fa5_bell" }, { "id": "h-ana", "label": "Analytics", "kind": "app", "sub": "Pinot · HDFS", "icon": "fa5_chart_bar" } ] } ], "note": "Stores are omitted here; act 4 places every one of them.", "meta": { "v": "1.0", "owner": "Enterprise Architecture", "date": "2026-09" } }, { "id": "03-actors-and-journeys", "title": "LinkedIn — Actors and Their Core Journeys", "layout": "actors", "groups": [ { "title": "Members", "kind": "boundary", "actors": [ { "id": "a-seek", "label": "Job seeker", "sub": "assumed 50M / month", "goal": "Find a role that fits me, and always know where my application stands.", "journeys": [ { "id": "j-apply", "label": "Search and apply to a job", "sub": "view 04" }, { "label": "Track my applications" }, { "label": "Get a job alert" } ] }, { "id": "a-pro", "label": "Professional", "sub": "1.2B members", "goal": "Keep up with the people I have worked with, and be found by the right ones.", "journeys": [ { "id": "j-connect", "label": "Connect with someone I met", "sub": "view 17" }, { "label": "Catch up on my feed", "sub": "view 14" }, { "label": "Message a connection", "sub": "view 18" } ] }, { "id": "a-creator", "label": "Creator", "sub": "assumed 8M posts / day", "goal": "Publish something useful and watch it reach the people who care about it.", "journeys": [ { "id": "j-post", "label": "Publish a post with video", "sub": "view 05" }, { "label": "Reply to comments" }, { "label": "Read post analytics" } ] } ] }, { "title": "Hirers and buyers", "kind": "lane", "actors": [ { "id": "a-rec", "label": "Recruiter", "sub": "paid seat", "goal": "Find qualified people who are open to a move, and get a reply from them.", "journeys": [ { "id": "j-recruit", "label": "Search and reach out", "sub": "view 06" }, { "label": "Manage a shortlist" } ] }, { "id": "a-emp", "label": "Employer admin", "sub": "company page", "goal": "Post a job and represent my company without buying a recruiter seat.", "journeys": [ { "label": "Post and close a job" }, { "label": "Review applicants" }, { "label": "Publish a company update" } ] }, { "id": "a-adv", "label": "Advertiser", "sub": "via the Ads platform", "goal": "Put a sponsored post in front of a precise audience and pay only for delivery.", "journeys": [ { "label": "Run a sponsored campaign" } ] } ] }, { "title": "The people who run it", "kind": "onprem", "actors": [ { "id": "a-ts", "label": "Trust & Safety reviewer", "sub": "24x7 queues", "goal": "Decide the worst content first, and have every decision stand up on appeal.", "journeys": [ { "label": "Work the review queue", "sub": "view 30" }, { "label": "Take down a fake-account ring" } ] }, { "id": "a-sre", "label": "On-call SRE", "sub": "per service, 24x7", "goal": "See which colo or dependency is hurting members before members notice.", "journeys": [ { "label": "Shift traffic out of a colo", "sub": "view 22" }, { "label": "Triage an SLO burn", "sub": "view 24" } ] }, { "id": "a-mle", "label": "Relevance engineer", "sub": "feed, search, jobs", "goal": "Ship a better ranking model safely, behind a ramp I can reverse.", "journeys": [ { "label": "Ramp a model in an A/B test", "sub": "view 25" } ] } ] }, { "title": "Machines and partners", "kind": "cloud", "actors": [ { "id": "a-fan", "label": "Fan-out workers", "kind": "platform", "sub": "Samza · nearline", "goal": "Put a new post into every normal follower's inbox within seconds.", "journeys": [ { "label": "Fan out a post", "sub": "view 15" } ], "icon": "fa5_stream" }, { "id": "a-push", "label": "Offline push jobs", "kind": "platform", "sub": "Spark · daily", "goal": "Land fresh recommendations in Venice before members wake up.", "journeys": [ { "label": "Push derived data", "sub": "view 11" } ], "icon": "spark" }, { "id": "a-tpa", "label": "Third-party app", "kind": "external", "sub": "OAuth client", "goal": "Sign members in with LinkedIn and read only what they consented to.", "journeys": [ { "label": "Sign in with LinkedIn", "sub": "view 28" } ], "icon": "fa5_handshake" } ] } ], "note": "Member count is LinkedIn's published figure; every other volume is a planning assumption.", "meta": { "v": "1.0", "owner": "Product + Enterprise Architecture", "date": "2026-09" } }, { "id": "04-journey-job-seeker", "title": "User Journey — Job Seeker, Search to Status", "layout": "journey", "actor": { "label": "Job seeker", "sub": "mobile-first, actively looking", "goal": "Apply to a role that fits in minutes, not an evening", "trigger": "A job alert, or a bad week at the current job", "success": "Knows, without asking, where each application stands" }, "phases": [ { "title": "Look", "sub": "search + alerts" }, { "title": "Decide" }, { "title": "Apply", "moment": true }, { "title": "Wait", "sub": "days to weeks" }, { "title": "Hear back", "moment": true } ], "lanes": [ { "title": "What they do", "kind": "step", "cells": [ [ { "label": "Searches a role" }, { "label": "Opens a job alert" } ], [ { "label": "Reads the listing" }, { "label": "Sees who they know" } ], [ { "label": "Taps Easy Apply" }, { "label": "Attaches a resume" } ], [ { "label": "Checks My Jobs" } ], [ { "label": "Reads the update" } ] ] }, { "title": "Where", "kind": "touch", "cells": [ [ { "label": "Jobs search", "sub": "app + web", "icon": "fa5_search" } ], [ { "label": "Job page" } ], [ { "label": "Apply sheet" } ], [ { "label": "My Jobs" } ], [ { "label": "Push · email" } ] ] }, { "title": "How it feels", "kind": "emotion", "levels": [ "Hopeful", "Neutral", "Anxious" ], "points": [ 1, 2, 1, 0, 2 ] }, { "title": "Behind the glass", "kind": "system", "cells": [ [ { "label": "Galene jobs vertical", "icon": "fa5_search" }, { "label": "Job recs · Venice", "icon": "fa5_cubes" } ], [ { "label": "Jobs service", "icon": "fa5_briefcase" }, { "label": "Graph: who you know" } ], [ { "label": "Applications · MySQL", "icon": "fa5_clipboard_list" }, { "label": "Ambry resume", "icon": "fa5_archive" } ], [ { "label": "Status events" } ], [ { "label": "ATC notifications", "icon": "fa5_traffic_light" } ] ] }, { "title": "Where it hurts", "kind": "pain", "cells": [ [ { "label": "Closed jobs still listed" } ], [], [ { "label": "Double submit on retry" } ], [ { "label": "Silence after applying" } ], [] ] }, { "title": "What would fix it", "kind": "gain", "cells": [ [ { "label": "De-index on close" } ], [ { "label": "Warm intro via graph" } ], [ { "label": "Idempotency key" } ], [ { "label": "Status pushed on change" } ], [] ] }, { "title": "How we know", "kind": "metric", "cells": [ [ { "label": "Search p95 ≤ 300 ms" } ], [ { "label": "Save rate" } ], [ { "label": "Apply success 99.95%" } ], [ { "label": "Time to first status" } ], [ { "label": "Reply within 14 days" } ] ] } ], "note": "The trough is the wait: an application with no status is a structural gap, not a UX one.", "meta": { "v": "1.0", "owner": "Product + Enterprise Architecture", "date": "2026-09" } }, { "id": "05-journey-creator", "title": "User Journey — Creator, Draft to Reach", "layout": "journey", "actor": { "label": "Creator", "sub": "posts weekly, often with video", "goal": "Share a short video and see it land with my network", "trigger": "Something worth saying, usually on the move", "success": "Real reactions in the first hour, and numbers to learn from" }, "phases": [ { "title": "Draft" }, { "title": "Publish", "moment": true }, { "title": "First hour", "moment": true }, { "title": "Engage" }, { "title": "Measure" } ], "lanes": [ { "title": "What they do", "kind": "step", "cells": [ [ { "label": "Writes, adds a video" } ], [ { "label": "Taps Post" } ], [ { "label": "Watches for reactions" } ], [ { "label": "Replies to comments" } ], [ { "label": "Opens analytics" } ] ] }, { "title": "Where", "kind": "touch", "cells": [ [ { "label": "Composer", "icon": "fa5_mobile_alt" } ], [ { "label": "Composer", "icon": "fa5_mobile_alt" } ], [ { "label": "Feed", "icon": "fa5_rss" } ], [ { "label": "Notifications", "icon": "fa5_bell" } ], [ { "label": "Post analytics" } ] ] }, { "title": "How it feels", "kind": "emotion", "levels": [ "Proud", "Fine", "Deflated" ], "points": [ 1, 1, 0, 2, 1 ] }, { "title": "Behind the glass", "kind": "system", "cells": [ [ { "label": "Media upload · Ambry", "icon": "fa5_archive" } ], [ { "label": "Content service", "icon": "fa5_newspaper" }, { "label": "Espresso", "icon": "fa5_database" } ], [ { "label": "Fan-out · Samza", "icon": "fa5_stream" }, { "label": "FollowFeed", "icon": "fa5_rss" } ], [ { "label": "Comments" }, { "label": "ATC", "icon": "fa5_traffic_light" } ], [ { "label": "Pinot", "icon": "fa5_chart_bar" } ] ] }, { "title": "Where it hurts", "kind": "pain", "cells": [ [ { "label": "Upload dies on bad wifi" } ], [ { "label": "Stuck on processing" } ], [ { "label": "Reach looks like zero" } ], [ { "label": "Notification flood" } ], [ { "label": "Numbers a day late" } ] ] }, { "title": "What would fix it", "kind": "gain", "cells": [ [ { "label": "Resumable signed upload" } ], [ { "label": "Text live, media later" } ], [ { "label": "Early signals in seconds" } ], [ { "label": "Aggregated alerts" } ], [ { "label": "Real-time analytics" } ] ] }, { "title": "How we know", "kind": "metric", "cells": [ [ { "label": "Upload success" } ], [ { "label": "Post p95 ≤ 300 ms" } ], [ { "label": "Time to first view" } ], [ { "label": "Reply rate", "icon": "fa5_chart_line" } ], [ { "label": "Analytics freshness" } ] ] } ], "note": "The first hour is the trough: the ranker learns from early engagement a post cannot get while it is invisible.", "meta": { "v": "1.0", "owner": "Product + Enterprise Architecture", "date": "2026-09" } }, { "id": "06-journey-recruiter", "title": "User Journey — Recruiter, Search to First Reply", "layout": "journey", "actor": { "label": "Recruiter", "sub": "agency or in-house, paid seat", "goal": "Fill a hard-to-fill role from people who will answer", "trigger": "A new requisition with a deadline", "success": "A shortlist of interested, qualified people in a week" }, "phases": [ { "title": "Define" }, { "title": "Search" }, { "title": "Shortlist" }, { "title": "Reach out", "moment": true }, { "title": "Get a reply", "moment": true } ], "lanes": [ { "title": "What they do", "kind": "step", "cells": [ [ { "label": "Sets title, skills, place" } ], [ { "label": "Runs the search" } ], [ { "label": "Saves 20 profiles" } ], [ { "label": "Sends InMail" } ], [ { "label": "Waits for answers" } ] ] }, { "title": "Where", "kind": "touch", "cells": [ [ { "label": "Recruiter app" } ], [ { "label": "Recruiter search" } ], [ { "label": "Project pipeline" } ], [ { "label": "InMail composer" } ], [ { "label": "Inbox", "icon": "fa5_inbox" } ] ] }, { "title": "How it feels", "kind": "emotion", "levels": [ "Confident", "Neutral", "Frustrated" ], "points": [ 1, 2, 1, 1, 0 ] }, { "title": "Behind the glass", "kind": "system", "cells": [ [ { "label": "Query builder" } ], [ { "label": "Galene people", "icon": "fa5_search" }, { "label": "Privacy filter", "icon": "fa5_user_lock" } ], [ { "label": "Projects · MySQL", "icon": "fa5_clipboard_list" } ], [ { "label": "Messaging", "icon": "fa5_comments" }, { "label": "Credits · MySQL", "icon": "fa5_coins" } ], [ { "label": "Messaging", "icon": "fa5_comments" }, { "label": "ATC", "icon": "fa5_traffic_light" } ] ] }, { "title": "Where it hurts", "kind": "pain", "cells": [ [ { "label": "Skills named ten ways" } ], [ { "label": "Hidden profiles leak" } ], [ { "label": "Duplicates across seats" } ], [ { "label": "Credit spent on a block" } ], [ { "label": "Most InMails ignored" } ] ] }, { "title": "What would fix it", "kind": "gain", "cells": [ [ { "label": "Standardised skills" } ], [ { "label": "Filter at index + query" } ], [ { "label": "Shared team pipeline" } ], [ { "label": "Check block before debit" } ], [ { "label": "Rank by open to work" } ] ] }, { "title": "How we know", "kind": "metric", "cells": [ [ { "label": "Query refinements" } ], [ { "label": "Search p95 ≤ 300 ms" } ], [ { "label": "Saved per search" } ], [ { "label": "Credits refunded" } ], [ { "label": "InMail response rate" } ] ] } ], "note": "The reply is the trough, and the fix is a ranking signal, open to work, that privacy rules must let through.", "meta": { "v": "1.0", "owner": "Product + Enterprise Architecture", "date": "2026-09" } }, { "id": "07-layered-architecture", "title": "LinkedIn — Layered Architecture", "layout": "bands", "layerHeaderWidth": 150, "bands": [ { "name": "Experience", "nodes": [ { "id": "l-web", "label": "Web client", "kind": "app", "icon": "fa5_desktop" }, { "id": "l-mob", "label": "iOS / Android", "kind": "app", "icon": "fa5_mobile_alt" }, { "id": "l-prt", "label": "Partner apps", "kind": "external", "icon": "fa5_handshake" } ] }, { "name": "Edge and API", "nodes": [ { "id": "l-afd", "label": "Azure Front Door", "kind": "integration", "icon": "azure_frontdoor" }, { "id": "l-ats", "label": "Traffic tier", "kind": "integration", "sub": "ATS", "icon": "fa5_route" }, { "id": "l-api", "label": "API layer", "kind": "integration", "sub": "GraphQL", "icon": "fa5_plug" }, { "id": "l-id", "label": "Identity", "kind": "security", "icon": "fa5_user_shield" } ] }, { "name": "Domain services", "nodes": [ { "id": "l-prof", "label": "Profile", "kind": "app", "icon": "fa5_id_card" }, { "id": "l-graph", "label": "Social graph", "kind": "app", "icon": "fa5_project_diagram" }, { "id": "l-cont", "label": "Content", "kind": "app", "icon": "fa5_newspaper" }, { "id": "l-feed", "label": "Feed broker", "kind": "app", "icon": "fa5_rss" }, { "id": "l-srch", "label": "Search", "kind": "app", "icon": "fa5_search" }, { "id": "l-msg", "label": "Messaging", "kind": "app", "icon": "fa5_comments" }, { "id": "l-jobs", "label": "Jobs", "kind": "app", "icon": "fa5_briefcase" } ] }, { "name": "Derived serving", "nodes": [ { "id": "l-cb", "label": "Couchbase", "kind": "store", "icon": "fa5_bolt" }, { "id": "l-ven", "label": "Venice", "kind": "store", "icon": "fa5_cubes" }, { "id": "l-liq", "label": "LIquid", "kind": "store", "icon": "fa5_project_diagram" }, { "id": "l-ff", "label": "FollowFeed", "kind": "store", "icon": "fa5_rss" }, { "id": "l-gal", "label": "Galene", "kind": "store", "icon": "fa5_search" } ] }, { "name": "Systems of record", "nodes": [ { "id": "l-esp", "label": "Espresso", "kind": "store", "icon": "fa5_database" }, { "id": "l-sql", "label": "MySQL", "kind": "store", "icon": "mysql" }, { "id": "l-amb", "label": "Ambry", "kind": "store", "icon": "fa5_archive" } ] }, { "name": "Streams and batch", "nodes": [ { "id": "l-brk", "label": "Brooklin", "kind": "integration", "icon": "fa5_exchange_alt" }, { "id": "l-kfk", "label": "Kafka", "kind": "queue", "icon": "kafka" }, { "id": "l-smz", "label": "Samza", "kind": "app", "icon": "fa5_stream" }, { "id": "l-hdp", "label": "Hadoop + Spark", "kind": "app", "icon": "hadoop" } ] }, { "name": "Platform", "nodes": [ { "id": "l-d2", "label": "D2 discovery", "kind": "platform", "icon": "fa5_sitemap" }, { "id": "l-hlx", "label": "Helix", "kind": "platform", "icon": "fa5_cogs" }, { "id": "l-trex", "label": "T-REX ramps", "kind": "platform", "icon": "fa5_flask" }, { "id": "l-obs", "label": "Observability", "kind": "platform", "icon": "fa5_heartbeat" } ] } ], "edges": [ { "from": "l-web", "to": "l-afd", "label": "HTTPS" }, { "from": "l-api", "to": "l-feed", "label": "Rest.li" }, { "from": "l-feed", "to": "l-ff", "label": "pull" }, { "from": "l-prof", "to": "l-esp", "label": "write" }, { "from": "l-esp", "to": "l-brk", "label": "change log", "kind": "async" }, { "from": "l-smz", "to": "l-ven", "label": "derived push", "kind": "async" } ], "note": "One arrow points up, by design: derived data is pushed back into the serving layer.", "meta": { "v": "1.0", "owner": "Enterprise Architecture", "date": "2026-09" } }, { "id": "08-container-architecture", "title": "LinkedIn — Container Architecture (one colo)", "layout": "nested", "canvas": { "width": 1760 }, "boxes": [ { "title": "LinkedIn · one serving colo (every colo runs the same stack)", "kind": "boundary", "dir": "col", "children": [ { "title": "Online tier · Rest.li mid-tier", "kind": "plain", "dir": "row", "children": [ { "title": "Edge and API", "kind": "boundary", "nodes": [ { "id": "c-ats", "label": "Traffic tier", "kind": "integration", "sub": "ATS · colo pinning", "icon": "fa5_route" }, { "id": "c-api", "label": "API layer", "kind": "integration", "sub": "GraphQL · Java", "icon": "fa5_plug" }, { "id": "c-id", "label": "Identity", "kind": "security", "sub": "Rest.li", "icon": "fa5_user_shield" } ] }, { "title": "Member services", "kind": "boundary", "nodes": [ { "id": "c-prof", "label": "Profile", "kind": "app", "sub": "Rest.li", "icon": "fa5_id_card" }, { "id": "c-graph", "label": "Social graph", "kind": "app", "sub": "Rest.li", "icon": "fa5_project_diagram" }, { "id": "c-msg", "label": "Messaging", "kind": "app", "sub": "Play · Akka · SSE", "icon": "fa5_comments" }, { "id": "c-jobs", "label": "Jobs", "kind": "app", "sub": "Rest.li", "icon": "fa5_briefcase" } ] }, { "title": "Discovery services", "kind": "boundary", "nodes": [ { "id": "c-cont", "label": "Content", "kind": "app", "sub": "Rest.li", "icon": "fa5_newspaper" }, { "id": "c-feed", "label": "Feed broker", "kind": "app", "sub": "second-pass rank", "icon": "fa5_rss" }, { "id": "c-srch", "label": "Search broker", "kind": "app", "sub": "federated", "icon": "fa5_search" }, { "id": "c-atc", "label": "Notifications", "kind": "app", "sub": "ATC on Samza", "icon": "fa5_bell" } ] } ] }, { "title": "Data tier", "kind": "plain", "dir": "row", "children": [ { "title": "Systems of record", "kind": "boundary", "nodes": [ { "id": "c-sql", "label": "MySQL", "kind": "store", "sub": "sharded", "icon": "mysql" }, { "id": "c-esp", "label": "Espresso", "kind": "store", "sub": "MySQL · Helix", "icon": "fa5_database" }, { "id": "c-amb", "label": "Ambry", "kind": "store", "sub": "blobs", "icon": "fa5_archive" } ] }, { "title": "Derived serving", "kind": "boundary", "nodes": [ { "id": "c-ff", "label": "FollowFeed", "kind": "store", "sub": "actor timelines", "icon": "fa5_rss" }, { "id": "c-ven", "label": "Venice", "kind": "store", "sub": "derived KV", "icon": "fa5_cubes" }, { "id": "c-liq", "label": "LIquid", "kind": "store", "sub": "graph", "icon": "fa5_project_diagram" }, { "id": "c-gal", "label": "Galene", "kind": "store", "sub": "search index", "icon": "fa5_search" }, { "id": "c-cb", "label": "Couchbase", "kind": "store", "sub": "cache", "icon": "fa5_bolt" } ] }, { "title": "Streams", "kind": "boundary", "nodes": [ { "id": "c-brk", "label": "Brooklin", "kind": "integration", "sub": "CDC", "icon": "fa5_exchange_alt" }, { "id": "c-kfk", "label": "Kafka", "kind": "queue", "sub": "local + aggregate", "icon": "kafka" }, { "id": "c-smz", "label": "Samza", "kind": "app", "sub": "nearline", "icon": "fa5_stream" } ] } ] } ] } ], "outside": [ { "id": "c-afd", "label": "Azure Front Door", "kind": "integration", "sub": "global edge", "icon": "azure_frontdoor" }, { "id": "c-push", "label": "APNs / FCM", "kind": "external", "icon": "fa5_paper_plane" }, { "id": "c-ofl", "label": "Offline platform", "kind": "app", "sub": "HDFS · Spark", "icon": "hadoop" } ], "edges": [ { "from": "c-ats", "to": "c-api", "label": "HTTPS" }, { "from": "c-api", "to": "c-id", "label": "session" }, { "from": "c-feed", "to": "c-ff", "label": "pull" }, { "from": "c-prof", "to": "c-esp", "label": "Rest.li write" }, { "from": "c-esp", "to": "c-brk", "label": "change log", "kind": "async" }, { "from": "c-brk", "to": "c-kfk", "kind": "async" }, { "from": "c-kfk", "to": "c-smz", "kind": "async" }, { "from": "c-atc", "to": "c-push", "label": "push", "kind": "async" } ], "note": "Edges are representative, not exhaustive; every service talks Rest.li over D2 inside the colo.", "meta": { "v": "1.0", "owner": "Platform Engineering", "date": "2026-09" } }, { "id": "09-integration-catalogue", "title": "LinkedIn — Integration Catalogue", "layout": "hub", "canvas": { "width": 1800 }, "left": { "title": "Who calls us", "nodes": [ { "id": "i-web", "label": "Web client", "kind": "app", "rel": "GraphQL", "icon": "fa5_desktop" }, { "id": "i-mob", "label": "iOS / Android", "kind": "app", "rel": "GraphQL", "icon": "fa5_mobile_alt" }, { "id": "i-prt", "label": "Partner apps", "kind": "external", "rel": "OAuth REST", "icon": "fa5_handshake" }, { "id": "i-ats", "label": "ATS partners", "kind": "external", "rel": "hourly feed", "kind2": "batch", "icon": "fa5_briefcase" }, { "id": "i-sso", "label": "Enterprise SSO", "kind": "external", "rel": "SAML", "icon": "fa5_key" } ] }, "centre": { "title": "Platform", "nodes": [ { "id": "i-core", "label": "LinkedIn Platform", "kind": "app", "sub": "versioned APIs only", "icon": "di2_linkedin" } ] }, "right": { "title": "What we call", "nodes": [ { "id": "i-push", "label": "Delivery providers", "kind": "external", "sub": "APNs · FCM · email · SMS", "rel": "on event", "dir": "out", "kind2": "async", "icon": "fa5_paper_plane" }, { "id": "i-idp", "label": "Google / Apple", "kind": "external", "rel": "OIDC", "dir": "out", "icon": "fa5_user_check" }, { "id": "i-rep", "label": "URL reputation", "kind": "external", "rel": "per link", "dir": "out", "icon": "fa5_shield_alt" }, { "id": "i-pay", "label": "Payments", "kind": "external", "rel": "on purchase", "dir": "out", "icon": "fa5_credit_card" }, { "id": "i-ads", "label": "Ads platform", "kind": "external", "rel": "per page", "dir": "out", "icon": "fa5_ad" } ] }, "note": "Kafka topics are never exposed to partners; every external contract is a versioned API.", "meta": { "v": "1.0", "owner": "Integration Architecture", "date": "2026-09" } }, { "id": "10-data-architecture-zones", "title": "LinkedIn — Data Architecture and Ownership", "layout": "nested", "canvas": { "width": 1760 }, "boxes": [ { "title": "Systems of record · replicated and backed up, never rebuilt", "kind": "boundary", "dir": "row", "children": [ { "title": "Espresso", "kind": "plain", "nodes": [ { "id": "z-prof", "label": "Profiles", "kind": "store", "sub": "member URN key", "icon": "fa5_id_card" }, { "id": "z-post", "label": "Posts + comments", "kind": "store", "sub": "author key", "icon": "fa5_newspaper" }, { "id": "z-edge", "label": "Connections", "kind": "store", "sub": "canonical pair key", "icon": "fa5_user_friends" }, { "id": "z-conv", "label": "Conversations", "kind": "store", "sub": "conversation key", "icon": "fa5_comments" } ] }, { "title": "MySQL", "kind": "plain", "nodes": [ { "id": "z-cred", "label": "Credentials", "kind": "store", "sub": "adaptive hashes", "icon": "fa5_key" }, { "id": "z-appl", "label": "Applications", "kind": "store", "sub": "idempotent writes", "icon": "fa5_clipboard_list" }, { "id": "z-bill", "label": "Credits + billing", "kind": "store", "sub": "ledger", "icon": "fa5_coins" } ] }, { "title": "Ambry", "kind": "plain", "nodes": [ { "id": "z-blob", "label": "Media originals", "kind": "store", "sub": "immutable blobs", "icon": "fa5_archive" } ] } ] }, { "title": "Derived online · rebuildable from the log or the lake", "kind": "boundary", "dir": "row", "children": [ { "title": "Graph and search", "kind": "plain", "nodes": [ { "id": "z-liq", "label": "LIquid", "kind": "store", "sub": "270B edges", "icon": "fa5_project_diagram" }, { "id": "z-gal", "label": "Galene", "kind": "store", "sub": "base + live index", "icon": "fa5_search" } ] }, { "title": "Feed", "kind": "plain", "nodes": [ { "id": "z-ff", "label": "FollowFeed", "kind": "store", "sub": "actor timelines", "icon": "fa5_rss" }, { "id": "z-inb", "label": "Feed inboxes", "kind": "store", "sub": "Venice hybrid", "icon": "fa5_inbox" } ] }, { "title": "Serving", "kind": "plain", "nodes": [ { "id": "z-ven", "label": "Venice", "kind": "store", "sub": "recs · features", "icon": "fa5_cubes" }, { "id": "z-cb", "label": "Couchbase", "kind": "store", "sub": "cache · TTL", "icon": "fa5_bolt" }, { "id": "z-pin", "label": "Pinot", "kind": "store", "sub": "member analytics", "icon": "fa5_chart_bar" } ] } ] }, { "title": "Log and lake · the replay source for everything above", "kind": "boundary", "dir": "row", "children": [ { "title": "Log", "kind": "plain", "nodes": [ { "id": "z-kfk", "label": "Kafka", "kind": "queue", "sub": "7 days + compacted", "icon": "kafka" } ] }, { "title": "Lake", "kind": "plain", "nodes": [ { "id": "z-hdfs", "label": "HDFS + Iceberg", "kind": "store", "sub": "OpenHouse tables", "icon": "hadoop" }, { "id": "z-feat", "label": "Feature store", "kind": "store", "sub": "Feathr", "icon": "fa5_cubes" } ] } ] } ], "outside": [ { "id": "z-dh", "label": "DataHub", "kind": "platform", "sub": "lineage · ownership", "icon": "fa5_sitemap" } ], "edges": [ { "from": "z-edge", "to": "z-kfk", "label": "CDC", "kind": "async" }, { "from": "z-kfk", "to": "z-hdfs", "label": "Gobblin", "kind": "batch" } ], "note": "Anything in the middle boundary can be rebuilt; only the top boundary needs backups.", "meta": { "v": "1.0", "owner": "Data Architecture", "date": "2026-09" } }, { "id": "11-online-nearline-offline", "title": "Data Flow — Online, Nearline, Offline", "layout": "swimlane", "laneHeaderWidth": 150, "stages": [ "Capture", "Transport", "Compute", "Serve" ], "lanes": [ { "title": "Online · milliseconds", "cells": [ [ { "id": "o1", "label": "Rest.li request", "kind": "integration", "icon": "fa5_plug" } ], [ { "id": "o2", "label": "Direct call", "kind": "integration", "sub": "D2 client-side LB", "icon": "fa5_sitemap" } ], [ { "id": "o3", "label": "In-process model", "kind": "app", "sub": "Quasar scoring", "icon": "fa5_brain" } ], [ { "id": "o4", "label": "Response", "kind": "app", "sub": "p95 ≤ 300 ms", "icon": "fa5_paper_plane" } ] ] }, { "title": "Nearline · seconds", "cells": [ [ { "id": "n1", "label": "Change capture", "kind": "integration", "sub": "Brooklin", "icon": "fa5_exchange_alt" } ], [ { "id": "n2", "label": "Kafka", "kind": "queue", "sub": "tracking + changes", "icon": "kafka" } ], [ { "id": "n3", "label": "Samza jobs", "kind": "app", "sub": "stateful", "icon": "fa5_stream" } ], [ { "id": "n4", "label": "Venice hybrid", "kind": "store", "sub": "nearline writes", "icon": "fa5_cubes" } ] ] }, { "title": "Offline · hours", "cells": [ [ { "id": "f1", "label": "Gobblin ingest", "kind": "integration", "icon": "fa5_cloud_upload_alt" } ], [ { "id": "f2", "label": "HDFS + Iceberg", "kind": "store", "icon": "hadoop" } ], [ { "id": "f3", "label": "Spark on Azkaban", "kind": "app", "sub": "daily DAGs", "icon": "spark" } ], [ { "id": "f4", "label": "Venice push", "kind": "store", "sub": "versioned bulk swap", "icon": "fa5_cubes" } ] ] } ], "edges": [ { "from": "n2", "to": "f1", "label": "hourly", "kind": "batch" }, { "from": "n4", "to": "o3", "label": "features", "kind": "sync" } ], "note": "Same data, three speeds: the online tier never computes what nearline or offline can precompute.", "meta": { "v": "1.0", "owner": "Data Architecture", "date": "2026-09" } }, { "id": "12-event-backbone", "title": "LinkedIn — Event Backbone", "layout": "hub", "canvas": { "width": 1800 }, "left": { "title": "Publishers · event · partition key on the arrow", "nodes": [ { "id": "e-prof", "label": "Identity + Profile", "kind": "app", "sub": "UserCreated · ProfileUpdated", "rel": "member", "kind2": "async", "icon": "fa5_id_card" }, { "id": "e-graph", "label": "Social graph", "kind": "app", "sub": "ConnectionCreated", "rel": "pair", "kind2": "async", "icon": "fa5_project_diagram" }, { "id": "e-cont", "label": "Content", "kind": "app", "sub": "PostCreated · Liked", "rel": "author", "kind2": "async", "icon": "fa5_newspaper" }, { "id": "e-msg", "label": "Messaging", "kind": "app", "sub": "MessageSent", "rel": "conv_id", "kind2": "async", "icon": "fa5_comments" }, { "id": "e-jobs", "label": "Jobs", "kind": "app", "sub": "JobApplied", "rel": "job", "kind2": "async", "icon": "fa5_briefcase" }, { "id": "e-trk", "label": "Tracking", "kind": "app", "sub": "views · clicks", "rel": "member", "kind2": "async", "icon": "fa5_chart_line" } ] }, "centre": { "title": "The log", "nodes": [ { "id": "e-kfk", "label": "Kafka", "kind": "queue", "sub": "100k+ topics · Avro", "icon": "kafka" } ] }, "right": { "title": "Consumers", "nodes": [ { "id": "e-fan", "label": "Feed fan-out", "kind": "app", "sub": "PostCreated", "rel": "lag ≤ 5 s", "dir": "out", "kind2": "async", "icon": "fa5_stream" }, { "id": "e-idx", "label": "Search indexers", "kind": "app", "sub": "entity changes", "rel": "lag ≤ 10 s", "dir": "out", "kind2": "async", "icon": "fa5_search" }, { "id": "e-atc", "label": "ATC notifications", "kind": "app", "sub": "graph · content · jobs", "rel": "lag ≤ 1 s", "dir": "out", "kind2": "async", "icon": "fa5_traffic_light" }, { "id": "e-rec", "label": "Recommendations", "kind": "app", "sub": "tracking · graph", "rel": "minutes", "dir": "out", "kind2": "async", "icon": "fa5_brain" }, { "id": "e-pin", "label": "Pinot", "kind": "store", "sub": "tracking", "rel": "lag ≤ 1 min", "dir": "out", "kind2": "async", "icon": "fa5_chart_bar" }, { "id": "e-abuse", "label": "Anti-abuse (CASAL)", "kind": "security", "sub": "signups · posts", "rel": "lag ≤ 5 s", "dir": "out", "kind2": "async", "icon": "fa5_user_secret" } ] }, "note": "No consumer is known to its publisher; adding a consumer never needs a publisher release.", "meta": { "v": "1.0", "owner": "Data Architecture", "date": "2026-09" } }, { "id": "13-core-data-model", "title": "LinkedIn — Core Data Model", "layout": "er", "canvas": { "width": 1720, "cols": 4 }, "rowGap": 230, "entities": [ { "id": "position", "name": "position", "kind": "store", "row": 0, "col": 0, "attrs": [ "position_id PK", "member_urn FK", "company_urn FK", "title, start, end" ] }, { "id": "profile", "name": "profile", "kind": "store", "row": 0, "col": 1, "attrs": [ "member_urn PK, FK", "headline", "vanity_url UNIQUE", "visibility settings" ] }, { "id": "member", "name": "member", "kind": "store", "row": 0, "col": 2, "attrs": [ "member_urn PK", "status", "home_colo", "created_at" ] }, { "id": "connection", "name": "connection", "kind": "store", "row": 0, "col": 3, "attrs": [ "pair_key PK (min, max)", "state", "requested_by", "idempotency_key" ] }, { "id": "company", "name": "company", "kind": "store", "row": 1, "col": 0, "attrs": [ "company_urn PK", "name", "page_admins" ] }, { "id": "follow", "name": "follow", "kind": "store", "row": 1, "col": 1, "attrs": [ "follower_urn PK", "followee_urn PK", "followee_type" ] }, { "id": "post", "name": "post", "kind": "store", "row": 1, "col": 2, "attrs": [ "post_urn PK", "author_urn FK", "visibility", "media_urns[]", "lifecycle" ] }, { "id": "reaction", "name": "reaction", "kind": "store", "row": 1, "col": 3, "attrs": [ "post_urn PK, FK", "actor_urn PK", "type" ] }, { "id": "job", "name": "job", "kind": "store", "row": 2, "col": 0, "attrs": [ "job_urn PK", "company_urn FK", "state", "location, skills[]" ] }, { "id": "application", "name": "application", "kind": "store", "row": 2, "col": 1, "attrs": [ "application_id PK", "job_urn FK", "member_urn FK", "idempotency_key UQ", "state" ] }, { "id": "comment", "name": "comment", "kind": "store", "row": 2, "col": 2, "attrs": [ "comment_urn PK", "post_urn FK", "parent_urn FK", "author_urn FK" ] }, { "id": "conversation", "name": "conversation", "kind": "store", "row": 2, "col": 3, "attrs": [ "conversation_urn PK", "participant_urns[]", "last_seq" ] }, { "id": "message", "name": "message", "kind": "store", "row": 3, "col": 3, "attrs": [ "conversation_urn PK", "seq PK", "sender_urn", "client_msg_id UQ" ] } ], "relations": [ { "from": "member", "to": "profile", "label": "1 : 1", "from_side": "w", "to_side": "e" }, { "from": "profile", "to": "position", "label": "1 : N", "from_side": "w", "to_side": "e" }, { "from": "company", "to": "position", "label": "1 : N", "from_side": "n", "to_side": "s" }, { "from": "member", "to": "connection", "label": "1 : N", "from_side": "e", "to_side": "w" }, { "from": "member", "to": "post", "label": "1 : N", "from_side": "s", "to_side": "n" }, { "from": "post", "to": "reaction", "label": "1 : N", "from_side": "e", "to_side": "w" }, { "from": "post", "to": "comment", "label": "1 : N", "from_side": "s", "to_side": "n" }, { "from": "company", "to": "follow", "label": "1 : N", "from_side": "e", "to_side": "w" }, { "from": "company", "to": "job", "label": "1 : N", "from_side": "s", "to_side": "n" }, { "from": "job", "to": "application", "label": "1 : N", "from_side": "e", "to_side": "w" }, { "from": "conversation", "to": "message", "label": "1 : N", "from_side": "s", "to_side": "n" } ], "note": "Every key is a URN. Member foreign keys on follow, reaction, comment and application are not drawn.", "meta": { "v": "1.0", "owner": "Data Architecture", "date": "2026-09" } }, { "id": "14-feed-read-sequence", "title": "Feed Read — Critical Flow", "layout": "sequence", "lifelines": [ { "id": "q-mem", "label": "Member app", "kind": "actor", "icon": "fa5_mobile_alt" }, { "id": "q-api", "label": "API layer", "kind": "integration", "icon": "fa5_plug" }, { "id": "q-brk", "label": "Feed broker", "kind": "app", "icon": "fa5_rss" }, { "id": "q-inb", "label": "Feed inbox", "kind": "store", "icon": "fa5_inbox" }, { "id": "q-ff", "label": "FollowFeed", "kind": "app", "icon": "fa5_rss" }, { "id": "q-cand", "label": "Recs + ads", "kind": "app", "icon": "fa5_brain" }, { "id": "q-feat", "label": "Features", "kind": "store", "icon": "fa5_cubes" }, { "id": "q-cont", "label": "Content", "kind": "app", "icon": "fa5_newspaper" } ], "messages": [ { "from": "q-mem", "to": "q-api", "label": "GET /v1/feed?cursor", "kind": "call" }, { "from": "q-api", "to": "q-api", "label": "session to member context", "kind": "self" }, { "from": "q-api", "to": "q-brk", "label": "feed page for member", "kind": "call" }, { "from": "q-brk", "to": "q-inb", "label": "inbox entries", "kind": "call" }, { "from": "q-brk", "to": "q-ff", "label": "high-degree timelines", "kind": "call" }, { "from": "q-ff", "to": "q-brk", "label": "top-k per shard (FPR)", "kind": "return" }, { "from": "q-brk", "to": "q-cand", "label": "recommended + ad candidates", "kind": "call" }, { "from": "q-cand", "to": "q-brk", "label": "timeout: drop, not fail", "kind": "error" }, { "from": "q-brk", "to": "q-feat", "label": "member + item features", "kind": "call" }, { "from": "q-brk", "to": "q-brk", "label": "second-pass rank", "kind": "self" }, { "from": "q-brk", "to": "q-brk", "label": "dedupe · diversity · ad slots", "kind": "self" }, { "from": "q-brk", "to": "q-cont", "label": "decorate URNs", "kind": "call" }, { "from": "q-cont", "to": "q-brk", "label": "hydrated, privacy-checked", "kind": "return" }, { "from": "q-brk", "to": "q-api", "label": "ranked page + cursor", "kind": "return" }, { "from": "q-api", "to": "q-mem", "label": "200 · p95 ≤ 300 ms", "kind": "return" } ], "note": "Inbox and feature returns are omitted; every call carries its own deadline inside the 300 ms budget.", "meta": { "v": "1.0", "owner": "Feed Engineering", "date": "2026-09" } }, { "id": "15-hybrid-fan-out", "title": "Post Distribution — Hybrid Fan-out", "layout": "swimlane", "laneHeaderWidth": 150, "stages": [ "Publish", "Classify", "Distribute", "Store", "Read" ], "lanes": [ { "title": "Normal author", "cells": [ [ { "id": "p1", "label": "PostCreated", "kind": "queue" } ], [ { "id": "p2", "label": "Degree under 10k", "kind": "decision" } ], [ { "id": "p3", "label": "Samza fan-out", "kind": "app", "sub": "write per follower", "icon": "fa5_stream" } ], [ { "id": "p4", "label": "Follower inboxes", "kind": "store", "sub": "Venice hybrid", "icon": "fa5_inbox" } ], [ { "id": "p5", "label": "Inbox read", "kind": "app", "sub": "one key lookup", "icon": "fa5_inbox" } ] ] }, { "title": "High-degree author", "cells": [ [ { "id": "p6", "label": "PostCreated", "kind": "queue" } ], [ { "id": "p7", "label": "Degree ≥ 10k", "kind": "decision" } ], [ { "id": "p8", "label": "Index only", "kind": "app", "sub": "no fan-out" } ], [ { "id": "p9", "label": "FollowFeed", "kind": "store", "sub": "actor timeline", "icon": "fa5_rss" } ], [ { "id": "p10", "label": "Pulled at read", "kind": "app", "sub": "merged by broker" } ] ] }, { "title": "Recommended", "cells": [ [ { "id": "p11", "label": "Engagement events", "kind": "queue" } ], [ { "id": "p12", "label": "Quality + policy", "kind": "decision" } ], [ { "id": "p13", "label": "Embedding retrieval", "kind": "app", "icon": "fa5_brain" } ], [ { "id": "p14", "label": "Candidate store", "kind": "store", "sub": "Venice", "icon": "fa5_cubes" } ], [ { "id": "p15", "label": "Blended", "kind": "app", "sub": "capped share" } ] ] }, { "title": "Sponsored", "cells": [ [ { "id": "p16", "label": "Campaign live", "kind": "external", "icon": "fa5_ad" } ], [ { "id": "p17", "label": "Targeting match", "kind": "decision" } ], [ { "id": "p18", "label": "Ads platform", "kind": "external", "sub": "auction per page", "icon": "fa5_ad" } ], [], [ { "id": "p19", "label": "Ad slots", "kind": "app", "sub": "policy positions", "icon": "fa5_ad" } ] ] } ], "note": "The 10k threshold is a tunable, set where fan-out write cost overtakes read-time merge cost.", "meta": { "v": "1.0", "owner": "Feed Engineering", "date": "2026-09" } }, { "id": "16-feed-ranking-pipeline", "title": "Feed Ranking Pipeline", "layout": "flow", "chain": true, "stages": [ { "title": "Candidates", "nodes": [ { "id": "r-inb", "label": "Inbox", "kind": "store", "sub": "fan-out on write", "icon": "fa5_inbox" }, { "id": "r-ff", "label": "FollowFeed", "kind": "store", "sub": "first-pass ranked", "icon": "fa5_rss" }, { "id": "r-rec", "label": "Recommended", "kind": "app", "icon": "fa5_brain" }, { "id": "r-ads", "label": "Sponsored", "kind": "external", "icon": "fa5_ad" } ] }, { "title": "Filter", "nodes": [ { "id": "r-priv", "label": "Privacy + blocks", "kind": "security", "icon": "fa5_user_lock" }, { "id": "r-mod", "label": "Moderation state", "kind": "security", "icon": "fa5_gavel" }, { "id": "r-seen", "label": "Seen dedupe", "kind": "app", "icon": "fa5_filter" } ] }, { "title": "Score", "nodes": [ { "id": "r-feat", "label": "Features", "kind": "store", "sub": "Venice · Feathr", "icon": "fa5_cubes" }, { "id": "r-spr", "label": "Second-pass ranker", "kind": "app", "sub": "Quasar model", "icon": "fa5_sort_amount_down" }, { "id": "r-chr", "label": "Chronological", "kind": "app", "sub": "degraded mode", "icon": "fa5_history" } ] }, { "title": "Policy", "nodes": [ { "id": "r-div", "label": "Diversity rules", "kind": "decision", "icon": "fa5_random" }, { "id": "r-slot", "label": "Ad slotting", "kind": "decision", "icon": "fa5_ad" } ] }, { "title": "Serve", "nodes": [ { "id": "r-deco", "label": "Decorate URNs", "kind": "app", "icon": "fa5_layer_group" }, { "id": "r-page", "label": "Feed page", "kind": "app", "sub": "p95 ≤ 300 ms", "icon": "fa5_rss" } ] } ], "edges": [ { "from": "r-spr", "to": "r-chr", "label": "ranker down", "kind": "error" } ], "note": "Ranking reads candidates and features; it never writes to feed storage, so either can change alone.", "meta": { "v": "1.0", "owner": "Feed Relevance", "date": "2026-09" } }, { "id": "17-connection-request-sequence", "title": "Connection Request — Idempotent Flow", "layout": "sequence", "lifelines": [ { "id": "c-a", "label": "Member A", "kind": "actor" }, { "id": "c-api", "label": "API layer", "kind": "integration", "icon": "fa5_plug" }, { "id": "c-abuse", "label": "Anti-abuse", "kind": "security", "icon": "fa5_user_secret" }, { "id": "c-graph", "label": "Graph service", "kind": "app", "icon": "fa5_project_diagram" }, { "id": "c-esp", "label": "Edge store", "kind": "store", "icon": "fa5_database" }, { "id": "c-kfk", "label": "Kafka", "kind": "queue", "icon": "kafka" }, { "id": "c-atc", "label": "ATC", "kind": "app", "icon": "fa5_traffic_light" }, { "id": "c-b", "label": "Member B", "kind": "actor" } ], "messages": [ { "from": "c-a", "to": "c-api", "label": "POST /connections + key", "kind": "call" }, { "from": "c-api", "to": "c-abuse", "label": "invite rate + risk", "kind": "call" }, { "from": "c-abuse", "to": "c-api", "label": "allow", "kind": "return" }, { "from": "c-api", "to": "c-graph", "label": "create invitation", "kind": "call" }, { "from": "c-graph", "to": "c-esp", "label": "insert if key unseen", "kind": "call" }, { "from": "c-esp", "to": "c-graph", "label": "created: pending", "kind": "return" }, { "from": "c-graph", "to": "c-kfk", "label": "InvitationSent", "kind": "async" }, { "from": "c-graph", "to": "c-api", "label": "201 invitation", "kind": "return" }, { "from": "c-api", "to": "c-a", "label": "201 Created", "kind": "return" }, { "from": "c-a", "to": "c-api", "label": "retry, same key", "kind": "error" }, { "from": "c-api", "to": "c-a", "label": "same 201, no new row", "kind": "return" }, { "from": "c-kfk", "to": "c-atc", "label": "invite event", "kind": "async" }, { "from": "c-atc", "to": "c-b", "label": "push + in-app", "kind": "async" }, { "from": "c-b", "to": "c-api", "label": "accept", "kind": "call" }, { "from": "c-api", "to": "c-graph", "label": "accept invitation", "kind": "call" }, { "from": "c-graph", "to": "c-esp", "label": "CAS pending to connected", "kind": "call" }, { "from": "c-graph", "to": "c-kfk", "label": "ConnectionCreated", "kind": "async" } ], "note": "One row keyed by the ordered member pair makes accept a single compare-and-set; adjacency lists are derived.", "meta": { "v": "1.0", "owner": "Graph Engineering", "date": "2026-09" } }, { "id": "18-messaging-delivery-sequence", "title": "Message Delivery — Ordered, Online and Offline", "layout": "sequence", "lifelines": [ { "id": "m-s", "label": "Sender", "kind": "actor" }, { "id": "m-api", "label": "API layer", "kind": "integration", "icon": "fa5_plug" }, { "id": "m-msg", "label": "Messaging", "kind": "app", "icon": "fa5_comments" }, { "id": "m-st", "label": "Conversation store", "kind": "store", "icon": "fa5_database" }, { "id": "m-kfk", "label": "Kafka", "kind": "queue", "icon": "kafka" }, { "id": "m-dfe", "label": "Delivery front-end", "kind": "app", "icon": "fa5_satellite_dish" }, { "id": "m-r", "label": "Recipient", "kind": "actor" }, { "id": "m-push", "label": "APNs / FCM", "kind": "external", "icon": "fa5_paper_plane" } ], "messages": [ { "from": "m-s", "to": "m-api", "label": "POST messages + client id", "kind": "call" }, { "from": "m-api", "to": "m-msg", "label": "send", "kind": "call" }, { "from": "m-msg", "to": "m-msg", "label": "participant? blocked?", "kind": "self" }, { "from": "m-msg", "to": "m-st", "label": "append, seq = last + 1", "kind": "call" }, { "from": "m-st", "to": "m-msg", "label": "seq N", "kind": "return" }, { "from": "m-msg", "to": "m-api", "label": "201 · seq N", "kind": "return" }, { "from": "m-api", "to": "m-s", "label": "sent", "kind": "return" }, { "from": "m-msg", "to": "m-kfk", "label": "MessageSent", "kind": "async" }, { "from": "m-kfk", "to": "m-dfe", "label": "for online recipients", "kind": "async" }, { "from": "m-dfe", "to": "m-r", "label": "SSE event ≤ 500 ms", "kind": "async" }, { "from": "m-r", "to": "m-dfe", "label": "delivered · read", "kind": "call" }, { "from": "m-dfe", "to": "m-kfk", "label": "receipt event", "kind": "async" }, { "from": "m-kfk", "to": "m-push", "label": "offline: push instead", "kind": "error" }, { "from": "m-push", "to": "m-r", "label": "notification", "kind": "async" } ], "note": "Order is the sequence number from one writer per conversation; delivery may reorder, the client re-sorts.", "meta": { "v": "1.0", "owner": "Messaging Engineering", "date": "2026-09" } }, { "id": "19-search-indexing-and-query", "title": "Search — Indexing and Query", "layout": "swimlane", "laneHeaderWidth": 160, "stages": [ "Source", "Transport", "Build", "Index", "Serve" ], "lanes": [ { "title": "Base index · weekly", "cells": [ [ { "id": "s1", "label": "HDFS snapshots", "kind": "store", "icon": "hadoop" } ], [ { "id": "s2", "label": "Azkaban DAG", "kind": "app", "icon": "fa5_cogs" } ], [ { "id": "s3", "label": "Index build", "kind": "app", "sub": "Hadoop · Spark", "icon": "spark" } ], [ { "id": "s4", "label": "Base index shards", "kind": "store", "sub": "Galene · Lucene", "icon": "fa5_search" } ], [] ] }, { "title": "Live updates · seconds", "cells": [ [ { "id": "s5", "label": "Espresso · MySQL", "kind": "store", "icon": "fa5_database" } ], [ { "id": "s6", "label": "Brooklin → Kafka", "kind": "queue", "icon": "fa5_exchange_alt" } ], [ { "id": "s7", "label": "Doc builder", "kind": "app", "sub": "Samza", "icon": "fa5_stream" } ], [ { "id": "s8", "label": "Live update buffer", "kind": "store", "sub": "in memory", "icon": "fa5_search" } ], [] ] }, { "title": "Query · ≤ 300 ms", "cells": [ [ { "id": "s9", "label": "Member query", "kind": "actor" } ], [ { "id": "s10", "label": "API layer", "kind": "integration", "icon": "fa5_plug" } ], [ { "id": "s11", "label": "Rewrite + spell", "kind": "app", "sub": "query tagging", "icon": "fa5_search" }, { "id": "s14", "label": "Typeahead", "kind": "app", "sub": "prefix index", "icon": "fa5_search" } ], [ { "id": "s12", "label": "Federated broker", "kind": "app", "sub": "7 verticals", "icon": "fa5_search" } ], [ { "id": "s13", "label": "Personalised ranker", "kind": "app", "sub": "graph distance", "icon": "fa5_sort_amount_down" } ] ] } ], "edges": [ { "from": "s12", "to": "s8", "label": "scatter · gather", "kind": "sync" } ], "note": "Each searcher serves base shard plus live buffer; the base index is rebuilt so deletes never accumulate.", "meta": { "v": "1.0", "owner": "Search Engineering", "date": "2026-09" } }, { "id": "20-notification-pipeline", "title": "Notifications — Generate, Decide, Deliver", "layout": "flow", "chain": true, "stages": [ { "title": "Trigger", "nodes": [ { "id": "n-kfk", "label": "Kafka events", "kind": "queue", "sub": "graph · content · jobs", "icon": "kafka" } ] }, { "title": "Generate", "nodes": [ { "id": "n-conc", "label": "Concourse", "kind": "app", "sub": "content candidates", "icon": "fa5_bell" }, { "id": "n-agg", "label": "Aggregator", "kind": "app", "sub": "Ana and 12 others", "icon": "fa5_layer_group" } ] }, { "title": "Decide", "nodes": [ { "id": "n-atc", "label": "ATC", "kind": "decision", "sub": "caps · channel", "icon": "fa5_traffic_light" }, { "id": "n-pref", "label": "Preferences", "kind": "store", "sub": "Espresso", "icon": "fa5_sliders_h" } ] }, { "title": "Store", "nodes": [ { "id": "n-inapp", "label": "Notification store", "kind": "store", "sub": "Espresso", "icon": "fa5_bell" }, { "id": "n-badge", "label": "Badge counts", "kind": "store", "sub": "Couchbase", "icon": "fa5_bolt" }, { "id": "n-dlq", "label": "Retry queue", "kind": "queue", "sub": "backoff + DLQ" } ] }, { "title": "Deliver", "nodes": [ { "id": "n-app", "label": "In-app", "kind": "app", "icon": "fa5_bell" }, { "id": "n-push", "label": "APNs / FCM", "kind": "external", "icon": "fa5_paper_plane" }, { "id": "n-mail", "label": "Email", "kind": "external", "icon": "fa5_envelope" } ] }, { "title": "Learn", "nodes": [ { "id": "n-trk", "label": "Tracking", "kind": "queue", "sub": "open · dismiss", "icon": "fa5_chart_line" } ] } ], "edges": [ { "from": "n-push", "to": "n-dlq", "label": "provider 5xx", "kind": "error" } ], "note": "Nothing here is on the path of the action that caused it; a dead pipeline delays alerts, it never fails a post.", "meta": { "v": "1.0", "owner": "Notifications Engineering", "date": "2026-09" } }, { "id": "21-media-pipeline", "title": "Media — Upload, Process, Deliver", "layout": "flow", "chain": true, "stages": [ { "title": "Upload", "nodes": [ { "id": "md-cl", "label": "Composer", "kind": "app", "sub": "web · mobile", "icon": "fa5_mobile_alt" }, { "id": "md-svc", "label": "Media service", "kind": "app", "sub": "issues signed URL", "icon": "fa5_image" }, { "id": "md-up", "label": "Resumable upload", "kind": "integration", "sub": "chunked · direct", "icon": "fa5_cloud_upload_alt" } ] }, { "title": "Store", "nodes": [ { "id": "md-amb", "label": "Ambry", "kind": "store", "sub": "originals · immutable", "icon": "fa5_archive" }, { "id": "md-q", "label": "Quarantine", "kind": "risk", "sub": "never served", "icon": "fa5_ban" } ] }, { "title": "Process", "nodes": [ { "id": "md-scan", "label": "Malware scan", "kind": "security", "icon": "fa5_virus" }, { "id": "md-img", "label": "Image resize", "kind": "app", "sub": "renditions", "icon": "fa5_image" }, { "id": "md-vid", "label": "Video transcode", "kind": "app", "sub": "HLS · adaptive", "icon": "fa5_video" }, { "id": "md-cls", "label": "Content classifier", "kind": "security", "icon": "fa5_eye" } ] }, { "title": "Publish", "nodes": [ { "id": "md-evt", "label": "MediaReady", "kind": "queue", "sub": "Kafka", "icon": "kafka" }, { "id": "md-post", "label": "Post attaches media", "kind": "app", "icon": "fa5_newspaper" } ] }, { "title": "Deliver", "nodes": [ { "id": "md-cdn", "label": "Media CDN", "kind": "integration", "sub": "Azure Front Door", "icon": "azure_cdn-profiles" }, { "id": "md-view", "label": "Viewer", "kind": "actor" } ] } ], "edges": [ { "from": "md-scan", "to": "md-q", "label": "infected", "kind": "error" } ], "note": "Bytes never pass through a Rest.li service: the client writes to storage on a signed URL.", "meta": { "v": "1.0", "owner": "Media Engineering", "date": "2026-09" } }, { "id": "22-deployment-topology", "title": "LinkedIn — Deployment Topology", "layout": "nested", "canvas": { "width": 1760 }, "boxes": [ { "title": "Global edge", "kind": "cloud", "nodes": [ { "id": "d-dns", "label": "Global DNS", "kind": "integration", "sub": "health-checked", "icon": "fa5_globe" }, { "id": "d-afd", "label": "Azure Front Door", "kind": "integration", "sub": "165+ PoPs · WAF", "icon": "azure_frontdoor" }, { "id": "d-cdn", "label": "Media CDN", "kind": "integration", "sub": "cache · signed URLs", "icon": "azure_cdn-profiles" } ] }, { "title": "Colo A · US · one of four serving colos", "kind": "onprem", "dir": "row", "children": [ { "title": "Fault zone 1", "kind": "boundary", "nodes": [ { "id": "d-a1", "label": "Traffic tier", "kind": "integration", "sub": "ATS", "icon": "fa5_route" }, { "id": "d-a2", "label": "Rest.li services", "kind": "app", "sub": "stateless pool", "icon": "java" }, { "id": "d-a3", "label": "Espresso replicas", "kind": "store", "sub": "partition leaders", "icon": "fa5_database" }, { "id": "d-a4", "label": "Kafka brokers", "kind": "queue", "sub": "rack-aware", "icon": "kafka" } ] }, { "title": "Fault zone 2", "kind": "boundary", "nodes": [ { "id": "d-b1", "label": "Traffic tier", "kind": "integration", "sub": "ATS", "icon": "fa5_route" }, { "id": "d-b2", "label": "Rest.li services", "kind": "app", "sub": "stateless pool", "icon": "java" }, { "id": "d-b3", "label": "Espresso replicas", "kind": "store", "sub": "followers", "icon": "fa5_database" }, { "id": "d-b4", "label": "Kafka brokers", "kind": "queue", "sub": "rack-aware", "icon": "kafka" } ] }, { "title": "Fault zone 3", "kind": "boundary", "nodes": [ { "id": "d-c1", "label": "Traffic tier", "kind": "integration", "sub": "ATS", "icon": "fa5_route" }, { "id": "d-c2", "label": "Rest.li services", "kind": "app", "sub": "stateless pool", "icon": "java" }, { "id": "d-c3", "label": "Espresso replicas", "kind": "store", "sub": "followers", "icon": "fa5_database" }, { "id": "d-c4", "label": "Kafka brokers", "kind": "queue", "sub": "rack-aware", "icon": "kafka" } ] } ] }, { "title": "Colos B, C and D · identical stack, all serving", "kind": "onprem", "dir": "row", "children": [ { "title": "Colo B · US", "kind": "boundary", "nodes": [ { "id": "d-colob", "label": "Full stack", "kind": "app", "sub": "active", "icon": "fa5_server" } ] }, { "title": "Colo C · US", "kind": "boundary", "nodes": [ { "id": "d-coloc", "label": "Full stack", "kind": "app", "sub": "active", "icon": "fa5_server" } ] }, { "title": "Colo D · APAC", "kind": "boundary", "nodes": [ { "id": "d-colod", "label": "Full stack", "kind": "app", "sub": "active", "icon": "fa5_server" } ] } ] } ], "outside": [ { "id": "d-ofl", "label": "Offline grid", "kind": "app", "sub": "HDFS · Spark · Azkaban", "icon": "hadoop" } ], "edges": [ { "from": "d-afd", "to": "d-b1", "label": "pinned colo" }, { "from": "d-a3", "to": "d-b3", "label": "in-colo replica" }, { "from": "d-c4", "to": "d-colod", "label": "Brooklin mirror", "kind": "async" } ], "note": "Fault zones inside a colo are this design's assumption; LinkedIn has published colo count, not intra-colo layout.", "meta": { "v": "1.0", "owner": "Site Reliability Engineering", "date": "2026-09" } }, { "id": "23-cicd-and-ramps", "title": "Delivery Pipeline, Canaries and Ramps", "layout": "flow", "chain": true, "stages": [ { "title": "Source", "nodes": [ { "id": "y-git", "label": "Multiproduct repo", "kind": "app", "sub": "trunk + review", "icon": "fa5_code_branch" } ] }, { "title": "Build", "nodes": [ { "id": "y-ci", "label": "CI build + tests", "kind": "app" }, { "id": "y-art", "label": "Artifact repo", "kind": "store", "sub": "signed" } ] }, { "title": "Gates", "nodes": [ { "id": "y-compat", "label": "Schema compat", "kind": "decision", "sub": "Rest.li · Avro", "icon": "fa5_file_contract" }, { "id": "y-sec", "label": "Security scan", "kind": "decision" }, { "id": "y-int", "label": "Integration tests", "kind": "decision" } ] }, { "title": "Deploy", "nodes": [ { "id": "y-can", "label": "Canary hosts", "kind": "app", "sub": "one colo", "icon": "fa5_server" }, { "id": "y-ekg", "label": "EKG verdict", "kind": "decision", "sub": "canary vs control", "icon": "fa5_heartbeat" }, { "id": "y-roll", "label": "Colo by colo", "kind": "app", "sub": "rolling deploy" } ] }, { "title": "Release", "nodes": [ { "id": "y-ramp", "label": "T-REX ramp", "kind": "app", "sub": "1% to 100%", "icon": "fa5_flask" }, { "id": "y-ab", "label": "A/B verdict", "kind": "decision", "sub": "guardrail metrics", "icon": "fa5_flask" }, { "id": "y-live", "label": "Fully ramped", "kind": "app" } ] } ], "edges": [ { "from": "y-ekg", "to": "y-art", "label": "fail: roll back", "kind": "error" }, { "from": "y-ab", "to": "y-ramp", "label": "ramp down", "kind": "error" } ], "note": "Deploy and release are separate acts: code ships dark, a ramp turns it on, and a ramp turns it off.", "meta": { "v": "1.0", "owner": "Developer Productivity", "date": "2026-09" } }, { "id": "24-observability", "title": "Observability and Operations", "layout": "grid", "laneHeaderWidth": 160, "columns": [ "Emit", "Collect", "Store", "Consume", "Act" ], "rows": [ { "title": "Metrics", "cells": [ [ { "id": "o-m1", "label": "Service metrics", "kind": "app", "sub": "RED + saturation", "icon": "fa5_chart_line" } ], [ { "id": "o-m2", "label": "Metrics agents", "kind": "integration" } ], [ { "id": "o-m3", "label": "Time-series store", "kind": "store" } ], [ { "id": "o-m4", "label": "inGraphs", "kind": "platform", "sub": "dashboards" } ], [ { "id": "o-m5", "label": "Iris page", "kind": "security", "sub": "SLO burn rate", "icon": "fa5_pager" } ] ] }, { "title": "Logs", "cells": [ [ { "id": "o-l1", "label": "Structured logs", "kind": "app" } ], [ { "id": "o-l2", "label": "Kafka log topics", "kind": "queue", "icon": "kafka" } ], [ { "id": "o-l3", "label": "Log index", "kind": "store" } ], [ { "id": "o-l4", "label": "Incident search", "kind": "platform" } ], [ { "id": "o-l5", "label": "Runbook link", "kind": "security" } ] ] }, { "title": "Traces", "cells": [ [ { "id": "o-t1", "label": "Trace context", "kind": "app", "sub": "per Rest.li hop" } ], [ { "id": "o-t2", "label": "Trace collector", "kind": "integration" } ], [ { "id": "o-t3", "label": "Trace store", "kind": "store" } ], [ { "id": "o-t4", "label": "Call-graph analysis", "kind": "platform" } ], [] ] }, { "title": "Member experience", "cells": [ [ { "id": "o-r1", "label": "Client timing", "kind": "app", "sub": "RUM beacons" } ], [ { "id": "o-r2", "label": "Tracking pipeline", "kind": "queue", "sub": "Kafka", "icon": "kafka" } ], [ { "id": "o-r3", "label": "Pinot", "kind": "store", "icon": "fa5_chart_bar" } ], [ { "id": "o-r4", "label": "ThirdEye", "kind": "platform", "sub": "anomaly detection", "icon": "fa5_chart_line" } ], [ { "id": "o-r5", "label": "Page product on-call", "kind": "security" } ] ] }, { "title": "Overload", "cells": [ [ { "id": "o-h1", "label": "Queue + latency", "kind": "app" } ], [ { "id": "o-h2", "label": "Hodor", "kind": "integration", "sub": "overload detector", "icon": "fa5_tachometer_alt" } ], [], [ { "id": "o-h4", "label": "Shed low priority", "kind": "platform" } ], [ { "id": "o-h5", "label": "Oncall schedule", "kind": "security", "sub": "who is woken", "icon": "fa5_pager" } ] ] } ], "note": "Empty cells are gaps, not omissions: traces page nobody, and overload state is not stored.", "meta": { "v": "1.0", "owner": "Site Reliability Engineering", "date": "2026-09" } }, { "id": "25-ml-lifecycle", "title": "Relevance ML Lifecycle", "layout": "cycle", "centre": { "label": "Pro-ML", "sub": "one ML platform" }, "nodes": [ { "id": "k1", "label": "Track", "kind": "queue", "sub": "impressions · clicks", "icon": "fa5_chart_line" }, { "id": "k2", "label": "Features", "kind": "store", "sub": "Frame · Feathr", "icon": "fa5_cubes" }, { "id": "k3", "label": "Train", "kind": "app", "sub": "Spark · TonY", "icon": "fa5_brain" }, { "id": "k4", "label": "Validate", "kind": "decision", "sub": "offline metrics", "icon": "fa5_clipboard_check" }, { "id": "k5", "label": "Deploy", "kind": "app", "sub": "Quasar · model repo", "icon": "fa5_rocket" }, { "id": "k6", "label": "Ramp", "kind": "decision", "sub": "T-REX A/B", "icon": "fa5_flask" }, { "id": "k7", "label": "Observe", "kind": "platform", "sub": "health assurance", "icon": "fa5_heartbeat" } ], "ringLabels": [ "labelled events", "training sets", "candidate", "passes gate", "live at 1%", "guardrails hold", "drift signals" ], "meta": { "v": "1.0", "owner": "AI Platform", "date": "2026-09" } }, { "id": "26-degradation-matrix", "title": "Graceful Degradation Contract", "layout": "grid", "laneHeaderWidth": 150, "columns": [ "Healthy", "Dependency slow", "Dependency down", "Colo lost" ], "rows": [ { "title": "Feed", "cells": [ [ { "id": "g-f1", "label": "Ranked, personalised", "kind": "app" } ], [ { "id": "g-f2", "label": "Skip recs, keep network", "kind": "opportunity" } ], [ { "id": "g-f3", "label": "Chronological + trending", "kind": "opportunity" } ], [ { "id": "g-f4", "label": "Served by next colo", "kind": "opportunity" } ] ] }, { "title": "Search", "cells": [ [ { "id": "g-s1", "label": "Federated, personalised", "kind": "app" } ], [ { "id": "g-s2", "label": "Fewer verticals", "kind": "opportunity" } ], [ { "id": "g-s3", "label": "Search off, rest up", "kind": "risk" } ], [ { "id": "g-s4", "label": "Served by next colo", "kind": "opportunity" } ] ] }, { "title": "Notifications", "cells": [ [ { "id": "g-n1", "label": "Seconds to device", "kind": "app" } ], [ { "id": "g-n2", "label": "Queued, delayed", "kind": "opportunity" } ], [ { "id": "g-n3", "label": "Backlog; actions succeed", "kind": "opportunity" } ], [ { "id": "g-n4", "label": "Replayed from Kafka", "kind": "opportunity" } ] ] }, { "title": "Messaging", "cells": [ [ { "id": "g-m1", "label": "Under 500 ms", "kind": "app" } ], [ { "id": "g-m2", "label": "Push, not SSE", "kind": "opportunity" } ], [ { "id": "g-m3", "label": "Store and forward", "kind": "opportunity" } ], [ { "id": "g-m4", "label": "Reconnect elsewhere", "kind": "opportunity" } ] ] }, { "title": "Profile read", "cells": [ [ { "id": "g-p1", "label": "Cache + Espresso", "kind": "app" } ], [ { "id": "g-p2", "label": "Stale cache allowed", "kind": "opportunity" } ], [ { "id": "g-p3", "label": "Espresso direct", "kind": "opportunity" } ], [ { "id": "g-p4", "label": "Served by next colo", "kind": "opportunity" } ] ] }, { "title": "Job apply", "cells": [ [ { "id": "g-j1", "label": "Strongly consistent", "kind": "app" } ], [ { "id": "g-j2", "label": "Retry with same key", "kind": "opportunity" } ], [ { "id": "g-j3", "label": "Fail closed, retry", "kind": "risk" } ], [ { "id": "g-j4", "label": "Idempotent replay", "kind": "opportunity" } ] ] } ], "note": "Each row degrades on its own non-critical dependency; red cells are where a member notices.", "meta": { "v": "1.0", "owner": "Site Reliability Engineering", "date": "2026-09" } }, { "id": "27-security-zones", "title": "Security Architecture — Trust Zones", "layout": "zones", "zones": [ { "title": "Internet · untrusted", "kind": "trust", "nodes": [ { "id": "v-mem", "label": "Member", "kind": "actor" }, { "id": "v-bot", "label": "Scraper / bot", "kind": "risk", "sub": "credential stuffing" } ] }, { "title": "Edge", "kind": "trust", "nodes": [ { "id": "v-afd", "label": "Front Door + WAF", "kind": "security", "sub": "DDoS · bot rules", "icon": "azure_frontdoor" }, { "id": "v-ats", "label": "Traffic tier", "kind": "integration", "sub": "ATS · colo pinning", "icon": "fa5_route" } ] }, { "title": "API perimeter", "kind": "trust", "nodes": [ { "id": "v-api", "label": "API layer", "kind": "integration", "sub": "session to principal", "icon": "fa5_plug" }, { "id": "v-id", "label": "Identity", "kind": "security", "sub": "MFA · ATO scoring", "icon": "fa5_user_shield" }, { "id": "v-rl", "label": "Rate limiter", "kind": "security", "sub": "per member + IP", "icon": "fa5_tachometer_alt" } ] }, { "title": "Service zone · mTLS", "kind": "trust", "nodes": [ { "id": "v-svc", "label": "Rest.li services", "kind": "app", "sub": "mTLS · D2", "icon": "java" }, { "id": "v-acl", "label": "ACL service", "kind": "security", "sub": "managed in Nuage", "icon": "fa5_user_lock" }, { "id": "v-pol", "label": "Privacy policy", "kind": "security", "sub": "every read path", "icon": "fa5_user_lock" } ] }, { "title": "Data · restricted", "kind": "trust", "nodes": [ { "id": "v-db", "label": "Espresso · MySQL", "kind": "store", "sub": "encrypted at rest", "icon": "fa5_database" }, { "id": "v-kms", "label": "KMS + secrets", "kind": "security", "sub": "envelope keys", "icon": "fa5_key" }, { "id": "v-aud", "label": "Audit log", "kind": "security", "sub": "Kafka to immutable", "icon": "fa5_file_contract" } ] } ], "edges": [ { "from": "v-mem", "to": "v-afd", "label": "HTTPS 443" }, { "from": "v-bot", "to": "v-afd", "label": "challenged", "kind": "error" }, { "from": "v-afd", "to": "v-ats", "label": "TLS" }, { "from": "v-ats", "to": "v-api", "label": "HTTPS" }, { "from": "v-api", "to": "v-svc", "label": "mTLS + principal" }, { "from": "v-svc", "to": "v-db", "label": "TLS" }, { "from": "v-acl", "to": "v-aud", "label": "access log", "kind": "async" } ], "note": "No path reaches a service without a principal, or a store without an ACL decision.", "meta": { "v": "1.0", "owner": "Security Architecture", "date": "2026-09" } }, { "id": "28-identity-and-access-flow", "title": "Identity and Access — Sign-in with Step-up", "layout": "sequence", "lifelines": [ { "id": "x-m", "label": "Member", "kind": "actor" }, { "id": "x-app", "label": "Client app", "kind": "app", "icon": "fa5_mobile_alt" }, { "id": "x-edge", "label": "Edge", "kind": "security", "icon": "fa5_route" }, { "id": "x-id", "label": "Identity", "kind": "security", "icon": "fa5_user_shield" }, { "id": "x-risk", "label": "ATO risk", "kind": "security", "icon": "fa5_user_secret" }, { "id": "x-cred", "label": "Credential store", "kind": "store", "icon": "fa5_key" }, { "id": "x-api", "label": "API layer", "kind": "integration", "icon": "fa5_plug" }, { "id": "x-svc", "label": "Rest.li service", "kind": "app" } ], "messages": [ { "from": "x-m", "to": "x-app", "label": "email + password", "kind": "call" }, { "from": "x-app", "to": "x-edge", "label": "POST /login", "kind": "call" }, { "from": "x-edge", "to": "x-edge", "label": "rate + bot check", "kind": "self" }, { "from": "x-edge", "to": "x-id", "label": "forward", "kind": "call" }, { "from": "x-id", "to": "x-cred", "label": "verify hash", "kind": "call" }, { "from": "x-id", "to": "x-risk", "label": "device, IP, velocity", "kind": "call" }, { "from": "x-risk", "to": "x-id", "label": "new device: step up", "kind": "return" }, { "from": "x-id", "to": "x-app", "label": "MFA challenge", "kind": "return" }, { "from": "x-m", "to": "x-app", "label": "passkey or TOTP", "kind": "call" }, { "from": "x-app", "to": "x-id", "label": "second factor", "kind": "call" }, { "from": "x-id", "to": "x-app", "label": "session + short token", "kind": "return" }, { "from": "x-app", "to": "x-api", "label": "GET /v1/feed + token", "kind": "call" }, { "from": "x-api", "to": "x-api", "label": "verify signature, expiry", "kind": "self" }, { "from": "x-api", "to": "x-svc", "label": "principal over mTLS", "kind": "call" }, { "from": "x-api", "to": "x-app", "label": "401 on expiry: refresh", "kind": "error" } ], "note": "Sign in with LinkedIn for third parties is the OAuth 2.0 / OIDC variant of steps 11 to 14.", "meta": { "v": "1.0", "owner": "Security Architecture", "date": "2026-09" } }, { "id": "29-privacy-authorization", "title": "Privacy and Authorization — Every Read Path", "layout": "flow", "chain": true, "stages": [ { "title": "Request", "nodes": [ { "id": "p-req", "label": "Profile request", "kind": "integration", "sub": "viewer, target", "icon": "fa5_plug" } ] }, { "title": "Authenticate", "nodes": [ { "id": "p-auth", "label": "Session to principal", "kind": "security", "icon": "fa5_user_shield" } ] }, { "title": "Relationship", "nodes": [ { "id": "p-blk", "label": "Block list", "kind": "store", "sub": "cached, both ways", "icon": "fa5_ban" }, { "id": "p-deg", "label": "Graph degree", "kind": "store", "sub": "LIquid", "icon": "fa5_project_diagram" } ] }, { "title": "Decide", "nodes": [ { "id": "p-blkd", "label": "Blocked?", "kind": "decision", "icon": "fa5_ban" }, { "id": "p-vis", "label": "Visibility rule", "kind": "decision", "sub": "public to private", "icon": "fa5_eye" } ] }, { "title": "Shape", "nodes": [ { "id": "p-mask", "label": "Field masking", "kind": "security", "sub": "per-field settings", "icon": "fa5_eye" }, { "id": "p-resp", "label": "Response", "kind": "app", "icon": "fa5_paper_plane" } ] }, { "title": "Record", "nodes": [ { "id": "p-aud", "label": "Access log", "kind": "security", "sub": "recruiter + admin", "icon": "fa5_file_contract" } ] } ], "edges": [ { "from": "p-blkd", "to": "p-resp", "label": "404, not 403", "kind": "error", "route": "gutter" } ], "note": "A blocked viewer gets not-found rather than forbidden, so the check itself leaks nothing.", "meta": { "v": "1.0", "owner": "Security Architecture", "date": "2026-09" } }, { "id": "30-abuse-and-moderation", "title": "Abuse Detection and Content Moderation", "layout": "swimlane", "laneHeaderWidth": 150, "stages": [ "Signal", "Detect", "Decide", "Act", "Audit" ], "lanes": [ { "title": "Fake accounts", "cells": [ [ { "id": "a1", "label": "Signup + login events", "kind": "queue" } ], [ { "id": "a2", "label": "Account risk model", "kind": "app", "sub": "cluster detection", "icon": "fa5_user_secret" } ], [ { "id": "a3", "label": "Risk threshold", "kind": "decision", "icon": "fa5_tachometer_alt" } ], [ { "id": "a4", "label": "Challenge / restrict", "kind": "security", "icon": "fa5_user_lock" } ], [ { "id": "a5", "label": "Decision log", "kind": "store", "icon": "fa5_file_contract" } ] ] }, { "title": "Content", "cells": [ [ { "id": "a6", "label": "PostCreated", "kind": "queue" } ], [ { "id": "a7", "label": "Classifiers", "kind": "app", "sub": "spam · hate · links", "icon": "fa5_eye" } ], [ { "id": "a8", "label": "Confidence routing", "kind": "decision", "icon": "fa5_route" } ], [ { "id": "a9", "label": "Hide · label · limit", "kind": "security", "icon": "fa5_ban" } ], [ { "id": "a10", "label": "Decision log", "kind": "store", "icon": "fa5_file_contract" } ] ] }, { "title": "Member reports", "cells": [ [ { "id": "a11", "label": "Report button", "kind": "actor", "icon": "fa5_flag" } ], [ { "id": "a12", "label": "Dedupe + priority", "kind": "app", "icon": "fa5_filter" } ], [ { "id": "a13", "label": "Human review", "kind": "decision", "sub": "T&S queue", "icon": "fa5_gavel" } ], [ { "id": "a14", "label": "Action + notify", "kind": "security", "icon": "fa5_bell" } ], [ { "id": "a15", "label": "Appeal record", "kind": "store", "icon": "fa5_file_contract" } ] ] }, { "title": "Fraudulent jobs", "cells": [ [ { "id": "a16", "label": "JobCreated", "kind": "queue" } ], [ { "id": "a17", "label": "Job fraud model", "kind": "app", "icon": "fa5_user_secret" } ], [ { "id": "a18", "label": "Hold for review", "kind": "decision", "icon": "fa5_gavel" } ], [ { "id": "a19", "label": "Close + ban poster", "kind": "security", "icon": "fa5_ban" } ], [ { "id": "a20", "label": "Decision log", "kind": "store", "icon": "fa5_file_contract" } ] ] } ], "edges": [ { "from": "a8", "to": "a13", "label": "low confidence" } ], "note": "Rules, models, reports and people all write the same decision log, so every action can be appealed.", "meta": { "v": "1.0", "owner": "Trust & Safety Engineering", "date": "2026-09" } } ]