Show HN: Crust – A CLI framework for TypeScript and Bun

We've been building Crust (https://crustjs.com/), a TypeScript-first, Bun-native CLI framework with zero dependencies. It's been powering our core product internally for a while, and we're now open-sourcing it.

The problem we kept running into: existing CLI frameworks in the JS ecosystem are either minimal arg parsers where you wire everything yourself, or heavyweight frameworks with large dependency trees and Node-era assumptions. We wanted something in between.

What Crust does differently:

- Full type inference from definitions — args and flags are inferred automatically. No manual type annotations, no generics to wrangle. You define a flag as type: "string" and it flows through to your handler.

- Compile-time validation — catches flag alias collisions and variadic arg mistakes before your code runs, not at runtime.

- Zero runtime dependencies — @crustjs/core is ~3.6kB gzipped (21kB install). For comparison: yargs is 509kB, oclif is 411kB.

- Composable modules — core, plugins, prompts, styling, validation, and build tooling are all separate packages. Install only what you need.

- Plugin system — middleware-based with lifecycle hooks (preRun/postRun). Official plugins for help, version, and shell autocompletion.

- Built for Bun — no Node compatibility layers, no legacy baggage.

Quick example:

  import { Crust } from "@crustjs/core";
  import { helpPlugin, versionPlugin } from "@crustjs/plugins";

  const main = new Crust("greet")
    .args([{ name: "name", type: "string", default: "world" }])
    .flags({ shout: { type: "boolean", short: "s" } })
    .use(helpPlugin())
    .use(versionPlugin("1.0.0"))
    .run(({ args, flags }) => {
      const msg = `Hello, ${args.name}!`;
      console.log(flags.shout ? msg.toUpperCase() : msg);
    });

  await main.execute();

Scaffold a new project:

  bun create crust my-cli

Site: https://crustjs.com GitHub: https://github.com/chenxin-yan/crust

Happy to answer any questions about the design decisions or internals.

Show HN: Crust – A CLI framework for TypeScript and Bun
github.com

> Versions before 1.0 do not strictly follow semantic versioning.

Sorry for being nitpicky, but yes they do. Semantic versioning[0] allows arbitrary changes while the major version is 0:

> Major version zero (0.y.z) is for initial development. Anything MAY change at any time. The public API SHOULD NOT be considered stable.

[0]: https://semver.org/

thanks for the catch, what we meant is that we’re not committing to strict stability guarantees yet, so APIs may still change as we iterate toward 1.0.

this is cool! i'd recommend fleshing out the README. Clicked on the link before the discussion and was a tad confused.

Psst, the GitHub link in your post is broken (it should be https://github.com/chenxin-yan/crust).