/backend
Python backends: patterns, APIs, and the glue between your app and the cloud.
Backend engineering the way I practice it: Python-heavy, database-aware, and biased toward boring, well-understood tools. Articles here cover API design, background jobs, caching, and the operational details that decide whether a service survives its second week in production.
Retries are guaranteed in distributed systems. Duplicate side effects are not. A deep dive into idempotency keys, the claim-first ledger pattern, and how to implement it in Django and PostgreSQL.
Build the SNS-to-SQS fan-out pattern where each consumer owns a private queue with its own retry policy and DLQ. Covers queue policies, raw message delivery, redrive config, and the delivery guarantees you actually get.
Upload files from the browser straight to S3 — no proxying through your backend. Presigned PUT URLs with Django, the s3v4 SignatureDoesNotMatch fix, and the exact CORS config you need.
Why AWS won the cloud, what it looks like from a backend engineer's seat, and the one setup mistake almost every beginner makes on day one.
Token-bucket implementation with per-user and per-IP scopes, atomic Lua scripts on Redis, and a management command to inspect current buckets.
Decorator that computes a stable task signature and refuses to enqueue a duplicate while an identical job is still pending or running.
Write domain events to an outbox table in the same transaction as your business writes; a worker drains the table to SNS or Kafka.
Companion repo for a CI/CD comparison article.