What Is a Proxy Cache?
A proxy cache (or pull-through cache) is a service that forwards dependency requests to an upstream registry, stores the responses, and serves later identical requests from its local copy. The first fetch goes upstream; subsequent ones are served locally and fast. It speeds up CI and shields it from upstream rate limits and outages.
Why it matters
Ephemeral CI runners re-download the same dependencies constantly, hammering public registries and slowing builds. A proxy cache turns repeated upstream fetches into fast local reads and keeps builds working when the upstream is down. Latchkey runs cache proxying close to its managed runners to cut dependency pull time.
Related concepts
- Also called a pull-through cache
- Shields builds from upstream rate limits and outages
- A mirror is a fuller copy, not just on-demand
Related guides
What Is a Package Mirror?A mirror is a complete local copy of an upstream package registry or repository, kept in sync so builds can f…
What Is an Artifact Repository?An artifact repository is a managed store for build outputs and dependencies, such as packages, libraries, an…
What Is Cache Hit Ratio?Cache hit ratio is the fraction of cache lookups served from the cache rather than recomputed or refetched, a…