Search the practice set
275 questions, 991 terms and 600 topics in 30 areas.
60 results for “Platform SLOs”
Internal Consumer SLO
A reliability commitment made to teams who cannot switch supplier, which is why it must be measured from their side rather than from the platform's.
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 Contract
The platform's promise to its consumers about interface stability, behaviour and support, treated with the same seriousness as an external API.
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.
Platform Team Product Model
Running an internal platform team with product management disciplines — users, roadmap, support, metrics — rather than as an infrastructure function.
Platform User Research
Treating engineers as users whose actual behaviour is observed rather than assumed, which is what separates a platform from a set of shared tools.
Platform as a Product
Running an internal platform with the disciplines of a product — voluntary adoption, user research, documentation and a roadmap — rather than as a mandated standard.
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
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 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 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
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 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 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.
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
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
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
You are asked to choose between a cloud data warehouse and a lakehouse for a new analytics platform. How do you decide?
What actually differs The gap has narrowed considerably, so the decision turns on fewer things than the marketing suggests. Format ownership. In a lakehouse, da
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 are designing the network for a platform expected to run for a decade, spanning multiple regions, with acquisitions likely. What do you decide on day one and why?
The decision that cannot be undone The address space allocation. It is chosen on day one, usually by whoever creates the first VPC, and it constrains the next d
You are forming a platform team of four to serve twelve product teams. What do you build first?
Not a platform. One golden path. Four people cannot build an internal developer platform for twelve teams. They can make one journey excellent, and expand from
You are starting a greenfield platform. How do you establish what the architecture must satisfy before designing anything?
Separate three different things first Requirements can be traded against one another. Constraints cannot — a design violating one is not a trade off but a failu
You need funding for eighteen months of platform work with no customer-visible features. How do you build the case?
Do not lead with the technology "We need to modernise the platform" is a request for trust. Lead with a number the business already recognises as a problem. Fin
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
Your company needs a feature flag and experimentation platform. A vendor charges a substantial annual fee; a team estimates six weeks to build one. Decide.
Apply the differentiation test first Is this a source of competitive advantage? Feature flagging is context, not core: customers do not choose you for it, and b
Your internal platform has been live for a year. Six of twenty teams use it; the rest built their own pipelines. The CTO proposes mandating it. What is your advice?
Advise against the mandate, and say why in terms of evidence A mandate converts a usability problem into a compliance problem. It will produce adoption numbers
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
Your platform is built on an append-only event log with a lakehouse behind it. Legal asks how you will satisfy erasure requests within 30 days. What is your answer?
Establish the actual scope first Erasure applies to personal data held about the subject, and it has exceptions — data retained under a separate legal obligatio
Your platform runs across three availability zones. How would you determine whether it actually survives losing one?
Start with the arithmetic, because it usually fails there Steady state utilisation must stay below (N−1)/N. Three zones means below 67%. At 70%, losing one leav
Your platform team is now a ticket queue — every environment, every permission, every new service goes through them. How do you get out of it?
Categorise the queue before automating anything Take a month of tickets and group them. The distribution is always uneven, and two or three categories are usual
Your platform team of five spends nearly all its capacity upgrading control planes across 38 Kubernetes clusters. How did this happen and how do you fix it?
How it happened There is no split axis, only history. Clusters were created per project, per experiment, per team, per acquisition — each for a reason that was
A CDO proposes moving to a data mesh because the central data team is a bottleneck with a nine-month backlog. How do you assess the proposal?
Agree with the diagnosis, examine the prescription The bottleneck is real and it is structural rather than a matter of capacity. A central team receives data fr
A logic bug means six months of a derived table are wrong. You must reprocess without disrupting live consumers. How?
Establish the blast radius first Which downstream tables, reports and extracts consumed the wrong data, and did any of it leave the organisation — a regulatory
A team is choosing between Iceberg, Delta and Hudi for a new lakehouse. How would you approach the decision?
The formats are more alike than the debate suggests All three provide the same core: atomic commits over object storage, snapshots and time travel, schema evolu
A transformation project has grown to 600 models with chains twelve deep. A change at the base has an unknowable blast radius. What do you do?
Treat it as a software architecture problem, because it is one Six hundred models with twelve deep chains is a codebase with no module boundaries. The remedies
A warehouse table now feeds the CRM through reverse ETL. It breaks, and the analytics team and the CRM team each say it is the other's problem. How do you resolve it?
The dispute is a design gap, not a personality problem A warehouse table built for analysis — nightly latency, best effort availability, schema changes made by
Platform SLOs
Committing to reliability for internal consumers who cannot choose another provider.
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 API Deprecation
Removing something dozens of internal teams depend on, on a timeline that holds.
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.
Platform Team Topologies
Stream-aligned, enabling, complicated-subsystem and platform teams, and their interactions.
Platform Teams
Reducing other teams' cognitive load, measured by adoption.
Platform Telemetry
Instrumenting the platform itself: usage, friction, and where teams leave the paved road.
Platform Tenancy
Isolating teams sharing a cluster, account or pipeline fleet, and where isolation must be hard.
Platform as a Product
Adoption earned rather than mandated, with an owner and a roadmap.
Streaming SLOs
End-to-end latency, consumer lag and completeness as commitments rather than dashboards.
Abstraction Level Choice
How much to hide, and the leak that turns a helpful abstraction into a trap.