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Spawner

Documentation

These pages describe Spawner 2.2.0, released 10 October 2026. They come from the docs folder of its repository. Each page also exists in Markdown, for coding agents and language models: llms.txt lists them.

Start

Section titled “Start”
  • Quickstart: From a fresh Linux server to a first preview environment of your app, with its own URLs and database: install Spawner, log in, add a project, run spawner up.
  • Installing Spawner: Spawner, the self-hosted preview environment manager, installs on a Linux server dedicated to previews with one command, which also sets up Docker if needed.
  • Concepts: How Spawner works: projects and sources, environments and their URLs, jobs and statuses, sleep and lifetime, roles and tokens, protected previews, and its limits.

Guides

Section titled “Guides”
  • The .spawner/ directory: spawner.yaml and the compose file: Reference of .spawner/: spawner.yaml (project, URLs, seed, other repositories), the Docker Compose file with its variables and rules, and cheap environments.
  • Preview environments for coding agents: Give Claude Code, Codex, Cursor or any coding agent a preview environment of its branch, from its worktree: the spawner CLI with JSON output, or its MCP server.
  • Previews for pull requests: A Spawner preview environment for each pull request, from GitHub Actions or GitLab CI: spawner up at each push, its URL in a comment, spawner down when it closes.
  • Examples: Two projects ready to deploy sit in the examples/ directory of the repository: Node.js with PostgreSQL, and Laravel, Next.js and MySQL.

Reference

Section titled “Reference”
  • The Spawner CLI and MCP server: The spawner CLI creates, updates and deletes preview environments from a worktree, runs commands in them and reads their logs, with JSON output and an MCP server.
  • Configuring a Spawner server: Every setting of a Spawner server, read from the environment of its container: access, application, engine, lifecycle and limits, updates.

Operate

Section titled “Operate”
  • Security: How Spawner treats unreviewed branches: the compose policy, network isolation, access and protected previews, secrets, updates, and what it leaves to you.
  • Operating a Spawner server: Running a Spawner server day to day: where things are, settings, backups and restores, upgrades, disk space, monitoring, accounts and secrets.
  • Troubleshooting: When a Spawner preview environment does not start, does not answer or does not wake up: the message you see, what it means, and what to do.

Contribute

Section titled “Contribute”
  • Architecture: How Spawner is built, for those who read or change its code: the NestJS API and its engine, jobs, routing, the database, the Vue dashboard and the CLI.

What changed in each version is in the changelog.