Bun on Lambda Is Faster Than Node.js 22 — But Is It Production Ready?

Short summary

Bun runtime on AWS Lambda is ~3x faster than Node.js 22 in CPU-bound benchmarks but adds 3-5MB to deployment packages. Migration requires updating Lambda configuration and handling compatibility issues like different S3 error types. Evaluate deployment size impact before moving to production.

• •Bun shows 3x performance improvement over Node.js 22 in CPU-intensive Lambda tasks
• •Custom runtime adds 3-5MB to deployment package, impacting cold start times
• •Compatibility gotchas include different error types in native S3 client vs AWS SDK

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