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275 questions, 991 terms and 600 topics in 30 areas.
60 results for “Platform API Deprecation”
Deprecation Window
The stated period between announcing that an internal interface will be removed and removing it, with the removal actually happening at the end.
API Deprecation Policy
The published commitment about how long a version is supported, how notice is given, and what consumers can expect — without which nothing is ever retired.
Platform Contract
The platform's promise to its consumers about interface stability, behaviour and support, treated with the same seriousness as an external API.
API Gateway
A single entry point in front of a set of services that handles authentication, rate limiting, routing and protocol translation.
Booking.com's Experimentation Platform
Booking.com runs over a thousand concurrent experiments and treats the ability to test any change safely as a platform capability rather than a product feature.
Platform Lifecycle Constraint
The operating system's rules about when your process runs, which are not negotiable and invalidate most assumptions carried over from server code.
A new platform must serve a public partner API, three internal front-ends with different data needs, and high-volume service-to-service traffic. Choose the API styles and defend the choice.
Resist "pick one" These are three different problems with three different consumers. Standardising on one style optimises for architectural tidiness at the expe
Your API gateway configuration has grown to 8,000 lines with request transformations and cross-service orchestration. Changes require a platform team ticket and take two weeks. How do you fix this?
Name the failure The gateway has become a distributed monolith — shared, centrally owned, untestable in isolation, and on the critical path of every team's deli
You are designing APIs for a platform with a web app, a mobile app, internal service-to-service traffic and third-party partners. What do you expose, and where?
What the interviewer is testing Whether you choose per constraint or adopt one technology as an identity. The wrong answers here are all defensible sounding and
You must make a breaking change to an API used by 200 internal services and 40 external partners. Design the change and the migration.
First, verify it must break Many "breaking" changes are avoidable. Adding a field is safe if clients ignore unknown fields — which should be a documented expect
Your platform has 60 internal APIs. Teams repeatedly rebuild capabilities that already exist because they cannot find or understand them. What do you build?
The problem is discovery, then comprehension Duplication is the symptom. Teams are not choosing to rebuild; they cannot find what exists, or cannot tell in reas
A business sponsor asks for a real-time data platform because "the competition has one". Reporting is currently a nightly batch that lands at 06:00 and nobody has complained. How do you handle this?
Do not answer the technology question "Real time platform" is a solution, and it has arrived without a problem attached. Answering it directly leads either to a
A core mainframe system with no API supports nightly batch file exchange only. The business needs near-real-time order status. Design the integration.
Establish the real constraint "No API" usually means no API the mainframe team will build on your timeline . Find out what exists: message queue interfaces, dat
A design review presents a new event-driven platform. What cost questions do you ask before approving it?
What the interviewer is testing Whether cost is part of your architecture review or an afterthought handled by finance later, and whether you know the specific
A global SaaS product has a 200 ms p95 API budget. Users in Sydney see 900 ms against a single US-East deployment. The application team says the service responds in 40 ms. Who is right and what do you do?
Both are right, and that is the point The service does respond in 40 ms. The other 860 ms is network — and no amount of application profiling will show it, whic
A partner reports your API fails from their servers with a certificate error. It works in every browser you try and from your laptop. Diagnose and prevent.
The diagnosis An incomplete certificate chain. The server presents its own certificate but not the intermediates. Browsers frequently recover — they cache inter
A payments API must guarantee that a network retry never charges a customer twice. Design the mechanism end to end.
Why this is unavoidable A client that times out on a POST cannot know whether the request succeeded. Not retrying risks a lost payment; retrying risks a duplica
A platform of 40 services has logs only, and incidents take hours to diagnose. Design the observability strategy and its rollout order.
Why logs alone fail at this size Logs answer "what happened in this service". They cannot answer "where did this request spend its time across twelve services",
A platform team proposes adopting a service mesh for 40 services. Make the case for and against, then decide.
What it genuinely provides mTLS everywhere, with automated certificate rotation. This is usually the deciding factor. Doing mTLS by hand means short lived certi
A regulated client requires that no traffic between their data centre and your SaaS platform traverses the public internet. Design the connectivity and justify the cost.
Two distinct requirements hiding in one sentence Traffic must not traverse the public internet — a routing requirement. The client must be able to demonstrate i
A serverless API works in testing and fails under load with connection errors. The database is at 5% CPU. Explain and fix.
The mechanism Serverless functions scale by creating independent execution environments , each with its own process and its own connection pool. Two hundred con
A single deploy took down your monitoring platform. What happened, and how do you prevent a recurrence?
What almost certainly happened A high cardinality label was added to a metric. Each unique combination of label values is a separate time series, and cost scale
A team is about to launch a public GraphQL API. What must be in place before it goes live?
Query cost control — the security requirement An arbitrary query language exposed publicly means a client can construct a query that consumes unbounded resource
A team proposes exposing their service's database change stream via CDC so other teams can consume it, avoiding the work of building an event API. What is your assessment?
Name what is actually being proposed The proposal is to publish the service's internal schema as its integration contract. CDC does not emit domain events; it e
A team proposes moving an API to edge functions to reduce latency for international users. What do you check before agreeing?
Where is the data? This is the question that settles most edge proposals. Compute at the edge that calls back to a single region database has moved the compute
A team wants to build a new internal API on serverless functions. It will serve steady traffic of about 200 requests per second during business hours. What do you advise?
What the interviewer is testing Whether you can apply the serverless trade off to a specific workload rather than treating it as a default good or a default bad
A vendor claims their streaming platform provides exactly-once processing. How do you evaluate the claim?
Ask where the guarantee ends Nearly always at the platform's boundary. Within it, state and offsets commit together, so internal state reflects each input once.
After moving a service behind a VPN to an on-premises system, small API calls succeed and large responses hang indefinitely. Walk through the diagnosis.
What the symptom tells you Size dependent failure with a working handshake is a very specific signature. The connection establishes, so routing, firewall rules,
An AI feature launched two months ago now costs more per month than the rest of the platform. What do you investigate?
Get cost per request, decomposed Token cost splits into input and output, and they price differently. Break the bill down by feature, by user, and by input vers
An e-commerce platform stores card numbers to support repeat purchases. How do you reduce PCI scope?
Stop the card number reaching your systems at all The strongest reduction is not storing cards more safely; it is never receiving them. A hosted field or an ifr
An order API calls six services synchronously and takes 3 seconds at p95, failing whenever any dependency is degraded. Redesign it.
Diagnose with arithmetic Six synchronous dependencies at 99.9% each give 99.4% — roughly four hours a month, from components that are individually fine. And lat
Application teams say the platform is unreliable. The platform team's dashboard shows 99.95% on every component. How do you resolve this?
Both are right, and that is the finding The platform measured its components. Consumers experience journeys. The gap between those two views is where trust erod
Design a webhook delivery system for a platform with 10,000 customers. What are the hard parts?
Delivery, and its failure modes Persist the event first, deliver asynchronously. Delivery in the request path couples your latency and availability to every cus
Design an order submission API that is safe when the client cannot tell whether its request succeeded. What exactly do you store, and when?
What the interviewer is testing Whether you know that "make it idempotent" is a design with specific failure modes, not a checkbox. The core design The client g
Design rate limiting for a multi-tenant API where a single customer's traffic spike currently degrades service for everyone.
Name the problem precisely This is the noisy neighbour problem. Rate limiting is one control for it, and on its own it is incomplete — a customer within their l
Leadership asks for "five nines" across the platform. Engineering says it is impossible. Design the response.
Reframe the request "Five nines" is almost never what the business actually wants. 26 seconds of downtime per month is a number chosen for its rhetorical weight
Leadership asks whether to build an internal developer platform or buy one. Twelve teams, forty services, growing. How do you frame the decision?
Reject the framing as a binary Nobody builds or buys a whole platform. A platform is an assembly: source control, CI, artifact registry, infrastructure provisio
Platform API Deprecation
Removing something dozens of internal teams depend on, on a timeline that holds.
APIs as Products
Ownership, lifecycle, deprecation policy and developer experience.
Design Systems
Components as a versioned internal product, with adoption and deprecation like any API.
Partner & B2B Integration
External contracts, onboarding, sandboxes and long deprecation windows.
API & Integration
General material on integrating systems through contracts.
API Documentation
OpenAPI as a machine-checked contract rather than as prose.
API Error Handling
Error shapes, retryability signals and machine-readable causes.
API Gateway
A single entry point for policy, routing and protocol translation.
API Gateways
The single entry point, and the business logic that must stay out of it.
API Shapes for UI
REST, GraphQL and RPC judged by over-fetching, round trips and client coupling.
API Versioning
URL, header and account-pinned versioning, and who carries the burden.
Data Platform Architecture
General material on designing the analytical data estate end to end.
Data Platform Tenancy
Multiple domains on shared storage and compute, with separable access and cost.
Internal Developer Platform
The assembled surface teams actually touch, and what belongs behind it.
ML Platform
Feature stores, training pipelines, registries and deployment.
Platform APIs
Treating the platform's own interfaces as contracts with consumers and compatibility rules.
Platform Adoption
Migrating existing teams onto a platform without a mandate, and reading the adoption curve.
Platform Engineering
General material on internal platforms as products with users, adoption and lifecycles.
Platform Funding
Central cost, showback, chargeback, and justifying a team that ships no customer feature.
API & Integration Architecture
Contracts between systems, and the compatibility discipline that keeps them working.
Data Platform Architecture
The analytical estate: storage layout, ingestion, transformation and the compute that reads it.
Platform Engineering & Developer Experience
Building the product other engineers build on, and being judged on whether they use it.