Caching
What are snapshot runners?
Quick answer
Runners that boot from a filesystem image captured after your dependencies were installed, so install is skipped entirely.
The detail that matters
They help most when install dominates — Ruby, Python with native wheels, and large npm trees.
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.
Related
Why does Cargo rebuild everything?Your cache key changes on every run, or target/ is not cached at all.Why is cache restore slow?GitHub throttles cache bandwidth, so a multi-gigabyte cache can take minutes to restore.How do I write a good cache key?Hash exactly the files that determine the cached content — usually the lockfile — and nothing else.What are restore-keys?Ordered prefixes tried when the exact cache key misses, so a partial match can still be restored.