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fyrer is a declarative, language-agnostic monorepo task orchestrator written in Rust. In a large monorepo — whether it spans TypeScript, Rust, Go, Python, or any other language — running tasks across dozens of packages in the right order, without redundant rebuilds and without losing output, is painful. fyrer solves this by reading a single fyrer.yml config, turning your task relationships into a directed acyclic graph (DAG), and executing each level of that graph concurrently so you get the fastest possible run every time.

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What fyrer does

  • Reads fyrer.yml and resolves a task dependency graph — declare each package and its tasks; fyrer topologically sorts them and propagates failures so dependent tasks are cleanly skipped.
  • Runs tasks at each graph level concurrently — all tasks within the same DAG level execute in parallel, maximising CPU utilisation across your packages.
  • Streams colorized, prefixed output per task — every task’s logs are prefixed with its package and task name, colorized for readability, and streamed live.
  • Caches successful build tasks keyed by inputs — tasks with cache: true are fingerprinted using a blake3 hash of their command, environment, and all matched input files. A second run reports ⚡ Cached and restores outputs instantly.
  • Provides an interactive TUI and a plain CI-friendly mode — by default fyrer run opens a full-screen terminal UI with a task list and scrollable log pane. Pass -n (--no-tui) for plain prefixed output that works cleanly in CI pipelines and pipes.

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Who it’s for

fyrer is designed for developers who manage polyglot monorepos — repositories that combine multiple languages or runtimes such as TypeScript/Bun, Rust, Go, Python, and more — and who need a lightweight, zero-boilerplate tool to coordinate builds, tests, code-generation steps, and development servers across all of them. If you have ever written a Makefile or shell script just to sequence cargo build before bun run dev, fyrer is for you.

Installation

Install fyrer with the install script, npm, cargo install, or from source.

Quick Start

Run the bundled demo monorepo and learn the core commands in minutes.

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Limitations

Keep these known constraints in mind as you design your fyrer.yml:
  • Persistent tasks block later graph levels. Tasks within the same DAG level all start concurrently, but fyrer waits for an entire level to finish before advancing to the next. A persistent: true task (e.g. a dev server) never exits on its own, so any tasks that depend on it — or that share a later graph level — will never start. Keep long-running dev servers on the leaves of the dependency graph so they don’t block other work.
  • watch is not yet implemented. The watch flag is part of the config schema and is recognised without error, but the underlying file-watcher that would trigger automatic task restarts is not yet wired up. Tasks marked watch: true will run once and not restart on file changes.