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Every Proliferate session runs inside a sandbox- an isolated cloud environment with your repos, dependencies, Docker, secrets, and network access. Think of it as a ready-to-go dev machine for the agent, with the same tools your team uses locally.
Sandbox workspace showing the chat and service panels.

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What’s in a sandbox?

Each sandbox comes with:
  • Your repos- Cloned and ready, with the correct branch checked out.
  • Docker- Full Docker and Docker Compose support. Run containers, spin up databases, pull images, start services.
  • Secrets- Your development-specific secrets (like .env.local) are injected securely at runtime and re-injected fresh on every resume.
  • Network access- Full outbound access to API services, package registries, and external tools. This is configurable and fully air-gapped self-hosted deployments are possible.
  • Actions- Secure access to your configured actions (GitHub, Linear, Sentry, and more). Agents and sandboex never get raw credentials- all access is intermediated via the gateway.
  • Coding agent- A terminal-based coding agent powered by the LLM of your choice (currently proudly powered by OpenCode!)

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Setting up a configuration

A configuration groups the repos for a project and saves the environment so every future session starts from the same place. You can set it up once, and then have every teammate reuse it forever.
1

Create a configuration

Go to Configurations and click New Configuration. Select the repos that make up your project and give it a name.
Configuration creation modal showing repo selection and naming fields.
2

Run a setup session

After creating the configuration, you’re dropped into a setup session. Here you (or the agent) install dependencies, start Docker containers, and do anything else you’d do when setting up a project locally.You can do this by chatting with the agent or by using the Terminal tool directly.
Setup session with the agent configuring the environment.
3

Configure service commands

Set up the commands that should run automatically when a session starts- things like pnpm install, docker compose up, or pnpm dev. You can configure both one-time setup commands (install dependencies) and long-running service commands (dev server, database, background workers) from the configuration’s detail page.
4

Set up secrets

Add your development secrets so they’re written into the files you need (like .env.local or any other config file) at the start of every session. Go to Settings > Secrets, add your key-value pairs, and scope them to specific repos or share them across your organization.Secrets are encrypted at rest and injected fresh every time a sandbox starts or resumes. They are never persisted in saved environments.
Secret configuration UI for injecting secrets into repo environment files.
5

Save

When everything is working, save the session. The environment is now a reusable configuration- every new session on this project starts from this saved state.
You can update a configuration at any time by running another setup session from the configuration’s detail page.

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Using sandboxes

Once your configuration is set up, every new session launches into the workspace. The workspace has a chat pane on the left and a set of tools on the right.
Workspace showing the tool tabs on the right panel.
Live preview of your running application. When the agent (or you) starts a dev server, Proliferate detects the running service and exposes it at a unique URL. Anyone with the link can see the preview for 24 hours.Preview URLs are automatically included in Slack messages, Linear comments, GitHub PRs, and the web dashboard.
Manage long-running processes like dev servers, databases, and background workers. Start, stop, and restart services, and view their logs in real time.Service commands configured on your configuration run automatically when a session starts.
Services panel showing running services and logs.
A full VS Code editor running in the browser. Browse files, make edits, and use extensions- all inside the sandbox.
A full interactive terminal connected to the sandbox. Run commands, install packages, debug- anything you’d do in a local terminal.
Git operations without leaving the workspace. View diffs, switch branches, commit changes, push to remote, and create pull requests.
Git panel showing branch and commit operations.
View and edit environment variables and secrets for the current session. Changes are applied immediately without restarting the sandbox.
Env panel showing environment variables.
Browse artifacts and files created during the session. View verification screenshots, generated files, and other outputs the agent has produced.
Session info, snapshot management, auto-start configuration, and notification preferences.
Settings panel with session info and configuration.

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Snapshots

When you disconnect from a session, the sandbox state is saved automatically. When you reconnect, everything is restored- your filesystem, installed packages, running processes, and conversation history. Secrets are re-injected fresh on every resume and are never included in saved state.
Saving a setup session creates a reusable configuration snapshot. This is the fastest way to get sub-30-second startup for your project.