What a Go Engineer Learns Building Their First Real Python Service

Yogesh23012001 Posted on May 31 What a Go Engineer Learns Building Their First Real Python Service # ai # webdev # career # python I spent the last three years writing Go. At NPCI I built payment systems where the wrong defaults cost real money. At ShopUp I work on backend services that have to be right, fast, and observable in that order. This weekend I built my first real Python service: an idempotent task queue with a Postgres-backed worker, retries, dead-letter queue, full Prometheus observability, and a 16-test suite. From mkdir to GitHub release in eight hours. I want to write about what surprised me. Some of it was the language. Most of it wasn't. What I built The repo is here . The short version: an HTTP API that accepts tasks with an Idempotency-Key header (Stripe style), persists them to Postgres, and a separate async worker process that picks them up using SELECT ... FOR UPDATE SKIP LOCKED, runs them, and writes the outcome back. Same key + same body returns the cached response. Same key + different body returns 422. Failed tasks retry up to max_attempts; tasks that exhaust the budget go to a DEAD_LETTER state for operator review. This is the pattern most payment systems are built on. I've consumed it through Go libraries at NPCI; I'd never implemented it from scratch. Benchmark on my MacBook Air M2: 590 req/s on GET /tasks at concurrency 50, p50 67ms, p99 228ms. The latency tail is dominated by Postgres connection-pool contention — pool size 10 versus 50 concurrent requests means 40 of them are waiting. That's not a Python problem; that's the same problem I'd have in any language with the same pool configuration. Production fix is PgBouncer or a larger pool. What transferred from Go More than I expected. The mental model for state machines transferred cleanly. A task is PENDING, becomes PROCESSING when a worker claims it, ends as SUCCEEDED, FAILED, or DEAD_LETTER. The state guards are enforced in code the same way I'd enforce them in Go — return a 409 if