Design and evolve application programming interfaces so they meet functional requirements while minimizing disruption to clients and services. Core skills include designing resource oriented endpoints, choosing and implementing versioning strategies, and preserving backward compatibility. Candidates should understand versioning approaches such as embedding a version in the endpoint path, using request headers to select versions, and designing non breaking changes so explicit version bumps are avoided. Important topics include idempotency, pagination, filtering, sorting, error response design, status semantics, rate limiting, authentication and authorization, and considerations for low bandwidth or mobile clients. At senior levels discuss operational and lifecycle concerns: deprecation policies and timelines, migration plans, compatibility testing, handling multiple client versions simultaneously in production, rolling deployments and coexistence strategies, contract testing, and alternatives such as remote procedure call frameworks. Expect trade off discussions around developer experience, client upgrade friction, monitoring and instrumentation for versioned traffic, and communication strategies with downstream consumers.
MediumSystem Design
0 practiced
Design a distributed rate limiter for an API gateway that enforces both per-user limits (100 requests/min) and global limits (10,000 requests/min). Requirements: low latency, burst handling, consistency across multiple gateway instances, and per-version metrics. Describe algorithm choices, datastore options, consistency trade-offs, and failure modes.
MediumTechnical
0 practiced
A major client depends on auto-generated SDKs produced from your OpenAPI specs. You're introducing a backward-compatible optional response field and a small non-breaking endpoint change. Describe the process to update and publish SDKs across multiple languages, choose semantic version bumps, run compatibility tests, and communicate the update to clients with minimal disruption.
HardTechnical
0 practiced
Case study: A third-party payments provider announces a breaking API change that will be enforced in 6 months. As the Solutions Architect, create a prioritized plan: inventory usage, assess impact, design an adapter/abstraction layer, run tests in staging, create rollback/fallback options, and communicate timelines to stakeholders. Provide the sequence of technical actions you would take.
MediumTechnical
0 practiced
As a Solutions Architect, explain when you would choose gRPC over REST/JSON for internal microservice communication. Consider latency, payload size, streaming support, cross-language clients, browser compatibility, tooling (proto vs OpenAPI), and versioning implications. Provide concrete examples where gRPC is a strong fit and cases where REST is preferable.
MediumTechnical
0 practiced
Compare rate-limiting algorithms: fixed-window, sliding-window, token-bucket, and leaky-bucket. Explain how each behaves under bursty traffic, accuracy in distributed deployments, implementation complexity, and which use cases each suits best (e.g., per-user bursts vs steady throughput caps).
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