What is shippy?
The idea in 30 seconds
Most of a Rust build is compiling crates that someone, somewhere, already compiled from exactly the same inputs: your teammate, CI, or you on another branch yesterday. shippy notices that and hands you the finished files instead of compiling again.
It does this without replacing anything. You keep the real cargo and rustc. You type shippy build where you would type cargo build, and everything that builds today still builds.
What it does for real projects
Dev builds, measured on 2026-11-13. A "new checkout" is a fresh clone at a different path, with an empty target directory, after someone else has built once.
The first build on an empty cache costs a little more than cargo (135.3 s against 127.8 s on tempo): shippy is hashing and storing about a thousand results so the next build doesn't have to. See every number.
How it fits together
- Local first. shippy checks its own store on your machine. Most rebuilds after a branch switch or an undo end here.
- Then the box. On a miss it asks the shared server, which answers with results anyone may use.
- Then it gives back. What your machine compiled is uploaded in the background. If your token is untrusted, the box rebuilds it in a sandbox before anyone else sees it.