Decision notes on building production software — durable patterns and project retrospectives.http://localhost:4321/http://localhost:4321/notes/redis-singleflight/http://localhost:4321/notes/redis-singleflight/A 4-line pattern for de-duplicating expensive computations across processes when you don't need a full distributed lock.Thu, 30 Apr 2026 00:00:00 GMTrediscachingtilhttp://localhost:4321/playbook/caching/http://localhost:4321/playbook/caching/Cache layers, TTL vs invalidation, stampede protection, key hygiene, and the case for not caching at all.Sat, 25 Apr 2026 00:00:00 GMTcachingperformancearchitecturehttp://localhost:4321/playbook/api-design/http://localhost:4321/playbook/api-design/Resource shape, error envelopes, idempotency, pagination, and versioning. What I pick, why, and the failure mode each choice prevents.Sun, 12 Apr 2026 00:00:00 GMTapiarchitectureresthttp://localhost:4321/case-studies/prolearning/http://localhost:4321/case-studies/prolearning/A retro on building ProLearning end-to-end. What worked, what I'd redo, and the one decision that mattered most.Wed, 18 Mar 2026 00:00:00 GMTretroedtechproduct