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Async Programming

Async Best Practices

Avoiding common async mistakes and writing production-quality code

Interview: Backend architecture — senior level

Async Best Practices

Async code has unique pitfalls that can cause subtle bugs, deadlocks, and performance issues.

Critical Rules

  • Never block the event loop: Use run_in_executor for blocking code
  • Always await coroutines: Forgetting await returns a coroutine object
  • Use TaskGroup over gather: Better error propagation and cancellation
  • Handle cancellation: asyncio tasks can be cancelled at any await point