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How to reduce S3 transfer costs in CI
Cache and artifact traffic to S3 is expensive.
4 min read
Cache and artifact traffic to S3 is expensive.
Why it happens
Cache reads and writes cross the NAT gateway on every job unless a VPC endpoint is configured.
How to fix it
- Add an S3 gateway VPC endpoint — it is free and removes NAT charges for S3 entirely
- Set lifecycle rules to expire old cache objects
- Compress cache payloads; zstd is a good default
Your next build could be twice as fast, at half the price
Start free. Migrating away is the same one line, and we publish that diff too.
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