arenero
Open workspace

Cloud workspaces
for coding agents.

Source on GitHub

Run coding agents in
workspaces you can rewind.

Arenero gives your agent a cloud computer with a shell and persistent files. Save a snapshot before a change, test the result, and restore the workspace if you need to go back.

Open workspace See the workspace

Hosted access is by invitation. Self-host Arenero.

Connect from your terminal
npx @arenero/cli login
See the workspace
NEW YORK
City scenery
Day mode
New York · default view
About location

With automatic city selection, GeoJS uses your public IP to estimate your region. We pick the closest of ten illustrated cities. Arenero doesn’t store your IP or coordinates. You can choose any city instead.

Works with

Claude Code Codex OpenCode Cursor Other CLI agents

Review the work before you merge.

Connect a repository and start a project thread. Arenero forks a prepared workspace and checks out a separate branch. Follow the agent’s changes and try the running app before opening a pull request.

personal / weekend-projects Workspace running

Your promptBuild a board for collecting project ideas.

Build the idea board
Build a board for collecting project ideas.
arenero just now

I’ll build the board, then start the dev server so you can check it here.

Created your workspace
Built the idea board3 files
Started the live preview
Preview is runningPreview ready on port 3000

The first card is in place. The three changed files are in the Changes tab.

Ask for a change…
Claude Code
Live preview · localhost:3000

Project ideas

Things to build on a free weekend.

Browser extensionSave recipes
from any website
Backlog
1 idea

Example workspace: an agent builds an idea board on its own branch. Try the Preview, Terminal, and Changes tabs.

Keep control as your agent works

Read the architecture docs
A sandbox computer branches into two independent copies, each with its own terminal and files.

Go back to a saved workspace

Take a snapshot before a refactor. Rewind to restore that saved state, or fork it into an independent sandbox to try another approach. You can reuse the setup you already have.

Keep installs off your laptop

Your agent installs dependencies and runs commands inside a Firecracker microVM with its own shell and filesystem. The sandbox is isolated from the host and other workspaces. Your files stay there between sessions.

Try the app before opening a pull request

Run a dev server in the sandbox and use its preview beside the conversation. Check the behavior while you review the code, or share a signed preview URL with someone else.

Use integrations without handing over their secrets

A host-side proxy adds credentials to allowed requests outside the sandbox. Your agent can use the integration without receiving its secret. The proxy applies your network policy and records each outbound request.

Reconnect from your terminal.

Open a Bash shell to inspect files or run a command yourself. Create an API token in Settings → Tokens, then log in. Reconnect with the workspace ID to pick up where you left off.

CLI reference
arenero / CLI

# Connect with your dashboard API token

❯ npx @arenero/cli login

# Open a new workspace

❯ npx @arenero/cli sh

# Reconnect to an existing workspace

❯ npx @arenero/cli sh <id>
Node.js 22 or newer

Questions

Documentation
What does rewind restore?

Rewind restores the sandbox to a saved snapshot and removes later messages and turns from the thread. Take a snapshot before the change you want to be able to undo. Actions already taken in external services are outside that snapshot.

Do I need to install anything?

The dashboard runs in your browser. To connect from a terminal, you need Node.js 22 or newer and an API token from your dashboard settings.

Can I use the agents I already work with?

Yes. Arenero supports Claude Code, Codex, OpenCode, Cursor, and other CLI agents, alongside a built-in agent. Connect the accounts or API keys your chosen agent needs from your workspace settings.

Can I run Arenero myself?

Yes. The repository includes setup and deployment instructions. Firecracker isolation requires a Linux host with KVM. You can use the process driver for local development, without VM isolation.

How do I get access?

The hosted app currently uses workspace invitations. If you already have access, open your workspace and sign in. You can also follow the repository’s setup guide to run your own installation.

Give your next coding task its own workspace.

Have an invitation? Sign in and connect your repository. To run Arenero on your own infrastructure, follow the self-hosting guide.

Open workspace Self-hosting guide