The same commands as cargo, with blaze in front.
Blazingly fast Rust, literally.
Install · Try it · How fast · How it works · Docs
curl -fsSL https://raw.githubusercontent.com/indexable-inc/blaze/main/install.sh | shFor macOS on Apple silicon and Linux, with or without Rust installed: blaze downloads the Rust it builds with once (about 100 to 135 MB), or uses rustup's. Rather use crates.io or Nix? Other ways to install.
In any Rust project:
blaze run # like cargo run
blaze test # like cargo test
blaze build # like cargo build
The first build runs cargo, then waits a few seconds for blaze to load your project. Then change
a function and build again: it's back in milliseconds, and the Finished line says [ra-jit]
(blaze's engine). Every other cargo command passes straight through to cargo. Where cargo is
installed, cargo blaze run is the same as blaze run.
- Edits rebuild 10× faster on macOS arm64, 24× faster on Linux aarch64 and 11× faster on Linux x86-64 than with
cargo build, on average over real projects. - About 20 ms from saving a file to a running program using the new code, with live edits.
| Edit one function, then build (Linux x86-64) | cargo build |
cargo blaze build |
|---|---|---|
| ripgrep | 508 ms | 56 ms (9.1× faster) |
| nushell | 1.25 s | 236 ms (5.3× faster) |
| helix | 2.15 s | 116 ms (19× faster) |
| bun (1.25M lines of Rust) | 9.11 s | 451 ms (20× faster) |
Every project, platform, chart, and the memory and disk it takes: benchmarks.
blaze runs beside cargo and keeps your project compiled in memory. After an edit it compiles only the functions you changed and writes them into the program cargo already built, instead of linking it again from scratch. A program that opts in can take the new code while it keeps running. More.
- macOS on Apple silicon and Linux. On Windows every build is cargo's.
- Stable Rust. blaze builds your project with Rust 1.99.0 whatever toolchain it pins, so code that needs a nightly's features isn't for blaze yet.
- It trades memory for speed: a few GB for a small project.
- It's young. Keep
cargo checkor your CI as the final word, and tell us when something differs from cargo.
All the details: what works and what doesn't yet.
- Install: requirements, crates.io, Nix
- Using blaze: day to day, rebuild on save, making plain
cargo builduse blaze - Benchmarks: every number, how it's measured, and on what machines
- How it works: a map of the code
- Cargo compatibility: every command, flag and setting
- Hot reload: changing a running program
- CI runner and roadmap: where blaze is going
- Contributing
nix run github:indexable-inc/blazeThis opens a Game of Life window. On macOS on Apple silicon you can change its rules, colours and speed while it runs; elsewhere the window runs without live edits. It needs Nix, and builds blaze from source the first time.
For release news: Watch → Custom → Releases on GitHub.
How to build blaze from a checkout, run its tests and send a change: docs/contributing.md. To report a security problem: SECURITY.md.
blaze stands on the shoulders of giants. Thank you to the people who built:
- rust-analyzer, whose analysis and MIR blaze compiles from
- Cranelift (Bytecode Alliance), the fast code generator
- LLVM and inkwell, for the optimised tiers
- salsa, the incremental engine underneath
- object, for reading and writing executables
- Rust and its compiler crates
- rustd (DioxusLabs), whose code blaze includes
None of these projects endorses blaze.
blaze was called ra-jit until 2026-10-24; cargo ra-jit still works. Made at ix
for den's native app. MIT or Apache-2.0.