Incremental rust builds up to 92x faster than cargo/rustc

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 | sh

For 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.

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.

blaze is its own toolchain. It builds every project with its own Rust, blaze-2026-10-25 (today the nightly of that date), whatever the project pins; stable code and #![feature(...)] code build. Your toolchain and CI stay the final word (why).

It trades memory for speed: a few GB for a small project.

It's young. Keep cargo check or 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 build use 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

Demo: a Game of Life you can edit

nix run github:indexable-inc/blaze

This 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.

We're working with a few teams on fast Rust CI and remote builds, built on blaze. If your team waits on Rust builds, tell us what slows you down: andrew@ix.dev. Teams we work with get early access and a direct say in what we build next.

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:

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.