Technical interview guide

Working with APIs & Technical Specs

Reading and reviewing technical specs and API contracts well enough to catch problems before they ship.

Read: 32 min
Practice MCQs: 25
Interview QA: 25
Edition: v3
Editorial status: Reviewed
Relevant for: Product ManagerTechnical Product Manager

Scope: OpenAPI 3.2.0, HTTP RFC 9110/9111, Problem Details RFC 9457, OAuth Security BCP RFC 9700, JSON Schema 2020-12, OWASP API Top 10:2023, gRPC, Protobuf proto3, and W3C Trace Context current 2026-08-31.

Interview QA

Treat each question like a live interview question: answer out loud first (structure, assumptions, tradeoffs), then open the model answer to spot gaps and rehearse a tighter follow-up.

Curated: 2026-10-05 · Written: 2026-09-09 · Reviewed: 2026-10-03

QA-1

Review an API spec for creating payments.

QA-2

Decide whether an API change is backward compatible.

QA-3

Design retries for a mutation with an ambiguous timeout.

QA-4

Specify pagination for a rapidly changing feed.

QA-5

Design a useful API error model.

QA-6

Review authentication and authorization in an OpenAPI file.

QA-7

Plan the deprecation of a widely used endpoint.

QA-8

Write non-functional requirements for a public API.

QA-9

Review an asynchronous export API.

QA-10

Model partial updates without lost writes.

QA-11

Evaluate offset versus cursor pagination.

QA-12

Specify webhooks for business-critical events.

QA-13

Review a gRPC service specification.

QA-14

Design rate limits for a multi-tenant API.

QA-15

Threat-model an API that consumes third-party URLs.

QA-16

Introduce a new required field into an API workflow.

QA-17

Define caching for a personalized GET endpoint.

QA-18

Create a contract-test strategy for an API platform.

QA-19

Resolve disagreement over REST versus gRPC.

QA-20

Design distributed tracing requirements for an API.

QA-21

Review a spec that uses 200 for every response.

QA-22

Write acceptance criteria for an API integration feature.

QA-23

Investigate a specification that diverges from production.

QA-24

Review a bulk API operation.

QA-25