Gets machine-parseable JSON out of an LLM reliably — prefer provider-enforced grammar (OpenAI `response_format:{type:"json_schema",strict:true}`, Anthropic tool-calling / `tool_choice:{type:"tool"}`, Gemini `responseSchema`) over a "respond in JSON" prompt,…
Builds production data grids that stay fast and accessible at 10k–1M+ rows — decide server-side vs client-side sort/filter/paginate by the dataset-fits-in-memory test (client only under ~10k rows, otherwise push to the API and treat the table as a controlled…
Builds semantic/vector search — pick an embedding model + dimensionality (and whether to truncate Matryoshka dims) and the matching distance metric (cosine/dot/L2, normalize to unit length so cosine == dot and IP is correct), an ANN index with the…
Configures HTTP response security headers and a strict, nonce/hash-based Content-Security-Policy — script-src with a per-request nonce or sha256 hash plus 'strict-dynamic' (so you can drop host allowlists and 'unsafe-inline'), object-src 'none', base-uri…
Implements consumer-driven contract testing so services deploy independently without a full integration environment — the consumer's unit tests record concrete request/response expectations against a stub (Pact `pact-jvm`/`pact-js`/`pact-python`, or Spring…
Debugs a red CI job to root cause instead of blind-rerunning — reproduce locally in the SAME image (`act -j <job>`, `gitlab-runner exec`, `circleci local execute`, or `docker run` the exact pinned digest), read the full log + the real exit code (124=timeout,…
Diagnoses and fixes non-deterministic test failures at root cause instead of masking them with retries — classify the flake (test-order/shared-state pollution, async timing/sleep races, real-clock/timezone dependence, unseeded RNG, network/IO/external calls,…
Designs paginated list endpoints that stay correct and fast under concurrent writes — cursor/keyset pagination over a stable total ordering with a unique tie-break key (e.g. ORDER BY created_at DESC, id DESC and WHERE (created_at,id) < (?,?)), opaque…