Apache 2.0Join the open-source community

Open-source AI coding agent.

Haarness reads your code, makes the change, runs your tests and shows you every step.

Download for macOS Start in the cloudDownload for Windows Start in the cloudDownload for Linux Start in the cloudSend to my computer Start in the cloudSend to my computer Start in the cloudSend to my computer Start in the cloudDownload Start in the cloud

Free on your computer, with the models you already use

Haarness Desktop for macOS, Windows and LinuxLearn more

Haarness for iPhone · Coming soon to the App StoreLearn more

Haarness Desktop for macOS, Windows and LinuxLearn more

What is Haarness?

An open-source agent that writes, fixes and reviews code with you, in your terminal, your editor, a desktop app or the cloud.

Read the docs

Your ChatGPT or Copilot planSign in with ChatGPT or GitHub Copilot and use the plan you already pay for.
Any modelClaude, GPT, Gemini, Grok, Mistral, DeepSeek and more, or local models through Ollama and LM Studio.
Terminal, desktop and editorA fast terminal app, a native desktop app, and your editor through the Agent Client Protocol.
Agents side by sideRun several chats on the same project at once, each in its own worktree if you like.
You approve what mattersReview every step, or let a reviewer approve the routine ones. Undo any turn in one step.
It keeps goingClose the window and the work continues. Pick it up from Desktop, the terminal or your phone.

Use cases

From the first bug to the big migration

Fix bugsFrom a failing test to a fix you can merge.

It asks before anything sensitive, shows every step, and runs on a schedule in the cloud when you need it to.

It is not only for code. See what else people hand it

Everywhere you work

One agent.Everywhere you code.

In the terminal, in a desktop app, in your editor, in the cloud and on your phone: the same agent, with the same tools and the same rules.

Desktop app

A calm, native app for every project: chat, review changes, files and terminals side by side. For macOS, Windows and Linux.

Phone appsComing soon

Follow every task and approve the next step from your iPhone or Android phone. Until the apps reach their stores, any phone browser works.

Terminal

A fast terminal app and a scriptable command line, for people who live in the shell.

Cloud

Tasks that keep going after you close the laptop, and prompts that run on a schedule.

Your apps

Put the same agent in your product or your scripts, with the API and the TypeScript and Python SDKs.

const { text } = await chat.ask(
  "Summarise today's tickets"
);
send(text);

Also inside your editor, through the Agent Client Protocol. Set it up

Marketplace

Teach it your work.Plug in your tools.

Skills, agents, MCP servers, plugins and extensions give Haarness new know-how and new tools. Install one in a click, share it privately with your team, or publish your own.

Everywhere Haarness runsInstall once and use it in the CLI, in Desktop, in a Cloud workspace or in a Cloud agent's setup.

Private to your teamPublish skills, agents and tools only your account can see. Public items are reviewed before anyone else sees them.

Ask, and it finds oneHaarness can search the marketplace and install what a task needs.

Browse the marketplace

Made something others could use?Publish your own

Plug in the tools you already use. Any MCP server works.

GitHub
Linear
Notion
Figma
Jira
Sentry
Stripe
PostgreSQL
Supabase
Google Drive
HubSpot
Shopify

You stay in charge

Capable, and on your terms

An agent that edits your code needs limits you understand. Haarness shows its work, asks when it should, and lets you take a step back.

Choose what it may do

Approve sensitive steps as they come, or have it ask before every change. Your rules are plain text you can read.

See every step

Every file it read, every command it ran and every change it made, in order, with what it cost.

Undo in one stepTake back a turn and the file changes it made.
Your computer, your dataLocal work stays on your machine; only the requests you send reach the model you chose.
Keeps going without youClose the window and the work continues. Come back to a finished task.

Any model

Works with the AI you already use

Sign in with your ChatGPT or GitHub Copilot plan, bring your own keys, run models on your own machine — or use one Haarness account for all of them.

OpenAI
Anthropic
Gemini
xAI
Mistral
DeepSeek
GitHub Copilot
Groq
OpenRouter
Bedrock
Ollama
LM Studio

See every model and its price

Pricing

Free on your machine.Pay only for what the cloud runs.

Haarness costs nothing on your own computer. A Cloud plan funds three monthly allowances; idle machines stop on their own, and every request settles against a ledger you can read line by line.

1,000 credits = $1, at published rates
Purchased credits never expire
Overage only when you turn it on

See plans Model rates

Open source

Open at the core. Hosted when you want it.

The agent, the terminal app, Desktop, the server and the SDKs are Apache 2.0 and free on your computer. Haarness Cloud runs the same code for you, with workspaces that keep going and one account for everything.

How Haarness is built View on GitHub

For developers

Open protocols, all the way down

Script the CLI, embed the server, put Haarness in your editor, or point your own tools at the router.

Agent Client ProtocolUse Haarness as the agent inside your editor.
MCP, in and outConnect MCP servers over stdio, HTTP or SSE, with OAuth.
REST, SSE and OpenAPIEvery operation the clients use, with TypeScript and Python SDKs.
Haarness RouterPoint an existing SDK at one base URL, hosted or on your own server.

Read the docs SDKs and API

# The terminal app, in this folder
haarness

# One task, no window: text or JSON lines
git diff | haarness run "Review this change"

# The server every client talks to
haarness serve --port 4096

Questions

Before you install

Is Haarness free?: Yes, on your own computer. The agent, the terminal app and Desktop are open source under Apache 2.0. You pay your model provider as you do today, or nothing with a local model. Haarness Cloud is optional.
Do I need an API key?: No. Sign in with your ChatGPT or GitHub Copilot plan, use a model running on your own machine, or add an API key if you have one.
Will it change my code without asking?: Inside your project it edits files and runs commands so it can finish the job, and it asks before anything outside it, secrets or spending. Switch to Review to approve every step, and undo any turn in one click.
Does my code leave my computer?: Your code and chats stay on your machine. Model requests go to the provider you connect and nowhere else. A daily count of usage, never your code, comes to us unless you turn it off.
How is it different from other coding agents?: It is open source end to end, works with the models you already pay for, and keeps every chat on a local server, so the terminal, Desktop, your editor and your phone all share the same work.
What does it run on?: macOS, Windows and Linux: a terminal app, a desktop app, your editor through the Agent Client Protocol, and Haarness Cloud when you want it to run somewhere else.

Hand it the next ticket.

Download Haarness for your computer, or start in the cloud from your browser. It is the same agent either way.

Download for macOS Start in the cloud

$curl -fsSL https://haarness.ai/install.sh | sh

Download for Windows Start in the cloud

PS>irm https://haarness.ai/install.ps1 | iex

Download for Linux Start in the cloud

$curl -fsSL https://haarness.ai/install.sh | sh

Send it to your computer

Haarness installs on a Mac, Windows or Linux computer. Get the link by email and open it there.

Start in the cloud

Send it to your computer

Haarness installs on a Mac, Windows or Linux computer. Get the link by email and open it there.

Start in the cloud

Send it to your computer

Haarness installs on a Mac, Windows or Linux computer. Get the link by email and open it there.

Start in the cloud

Download Start in the cloud

$curl -fsSL https://haarness.ai/install.sh | sh