# Amber v1.17.0 — JavaScript and TypeScript runtime in Rust and V8

> Amber is a free, open-source (MIT) JavaScript and TypeScript runtime built with Rust and V8. One `amber` binary runs scripts, Jest-style tests, bundling, single-file compile, a small package installer, an HTTP serve command, and an opt-in capability sandbox for agent tools. It is not a drop-in Node.js replacement: each API is labeled Stable, Preview, Experimental, or Not supported.

HTML: https://amberjs.com/ · Index for agents: https://amberjs.com/llms.txt

## Key facts

- Current release: v1.17.0. Install: `curl -fsSL https://get.amberjs.com/install.sh | sh` (macOS/Linux) or `irm https://get.amberjs.com/install.ps1 | iex` (Windows PowerShell). See [Installation](https://amberjs.com/docs/installation.md).
- License: MIT, free and open source. Source: https://github.com/zh30/amberjs
- Pricing: none. Amber is free to use; there is no paid tier, plan, or license fee.
- Status labels: Stable / Preview / Experimental / Not supported, from [docs/CURRENT_SCOPE.md](https://github.com/zh30/amberjs/blob/main/docs/CURRENT_SCOPE.md). 69 Stable contracts (G1–G69). Full table: [Compatibility](https://amberjs.com/compatibility.md).
- Node conformance scorecard: 56/56 PASS on main.
- Amber is not a drop-in replacement for Node.js, Bun, or Deno, and publishes no current performance numbers.

Amber runs JavaScript and TypeScript files from a single `amber` binary. It ships a test runner, a bundler, a single-file compiler, a small package installer, an HTTP serve command, and a permission sandbox for running agent tools.

Amber is open source under the MIT license. The source lives at [github.com/zh30/amberjs](https://github.com/zh30/amberjs).

## What Amber is

- **A V8 runtime written in Rust.** The CLI runs scripts on V8 through `src/runtime_minimal.rs`. TypeScript and TSX are transpiled with oxc before they run.
- **One binary, many commands.** `amber run`, `amber test`, `amber bundle`, `amber compile`, `amber install`, and `amber serve` all live in the same executable.
- **A Node.js and Web API surface with written contracts.** Each Stable API has a contract file in `docs/` and an integration test in `tests/`. The contract lists what works and where it stops.
- **A host for agent tools.** `amber run --sandbox` denies file, network, environment, and process access unless you allow it. `amber session` and `amber mcp` call exported functions from a tool file over JSON-RPC.

## What Amber is not

Amber is **not** a drop-in replacement for Node.js, Bun, or Deno. Many Node modules are partial, and several are Preview. Use the [compatibility page](https://amberjs.com/compatibility.md) to check an API before you depend on it.

Amber does not publish performance numbers today. Older benchmark tables in the repository are historical and were not re-run for this release.

## How to read this manual

Every capability carries one of four labels:

| Label | Meaning |
| :--- | :--- |
| **Stable** | Pinned by a contract document and an executable test that runs in CI. Limits are listed next to the API. |
| **Preview** | In the default build and usable, but the contract or edge cases are still being tightened. |
| **Experimental** | Code exists, but it is not a product promise until it is re-verified. |
| **Not supported** | Deliberately out of scope. Amber fails closed instead of pretending. |

The single source of truth for these labels is [`docs/CURRENT_SCOPE.md`](https://github.com/zh30/amberjs/blob/main/docs/CURRENT_SCOPE.md). If this site and that file disagree, the file wins.

## Next steps

- [Install Amber](https://amberjs.com/docs/installation.md)
- [Run your first script](https://amberjs.com/docs/quick-start.md)
- [Browse the CLI](https://amberjs.com/docs/cli-usage.md)
- [Check Node.js compatibility](https://amberjs.com/docs/node-compat.md)


## Pages

- [Compatibility & scope](https://amberjs.com/compatibility.md)
- [Docs index](https://amberjs.com/docs.md)
- [Full text for agents](https://amberjs.com/llms-full.txt)