What Is a Remote Cache?
A remote cache is a build cache hosted in shared storage rather than on a single machine, so cached outputs produced by one runner or developer can be downloaded and reused by another. It turns work done anywhere into a speedup everywhere. Tools like Bazel, Turborepo, and Gradle support remote caches for exactly this reason.
Why it matters
On ephemeral CI runners, a local cache disappears when the machine is destroyed, so the next job rebuilds from scratch. A remote cache survives the runner, letting fresh ephemeral machines reuse prior work. Managed runner platforms often pair ephemeral runners with a remote cache to get both isolation and speed.
Related concepts
- Requires content-addressed, hermetic builds to be safe
- Cache poisoning is a risk if writes are not trusted
- Network transfer cost can offset savings for tiny artifacts
Related guides
What Is a Build Cache?A build cache stores intermediate build outputs so unchanged work can be reused across runs instead of recomp…
What Is a Hermetic Build?A hermetic build depends only on explicitly declared, pinned inputs and is isolated from the host, so it prod…
What Is an Ephemeral Runner?An ephemeral runner is a CI worker that runs exactly one job on a fresh machine, then is destroyed, giving ev…