# Warmbuild

> Warmbuild is a shared remote compilation cache for Xcode 26 and later. It plugs into Apple's built-in compilation caching, so GitHub Actions runners and every developer's Mac reuse what earlier builds already compiled. The same GitHub Action also selects the tests a change can reach, reuses test results that already passed, and reports where CI time goes (slow type-checking, warnings, symbolicated crashes). Coding agents use it through a CLI skill or a remote MCP server.

- Setup on CI: install the Warmbuild GitHub App, then add `- uses: warmbuild/action@v1` before `xcodebuild` (with `permissions: id-token: write`).
- Setup on a Mac: `curl -fsSL https://warmbuild.dev/install.sh | sh` in the repository, or `brew install warmbuild/tap/warmbuild` then `warmbuild login && warmbuild start`.
- `xcodebuild` commands stay unchanged. If the cache is unreachable, Xcode compiles as usual; a build never fails because of Warmbuild.
- Dashboard: https://warmbuild.dev/app/ · MCP server: https://mcp.warmbuild.dev/mcp

## Pricing

Free for most teams. Half the usual rate after that. (Proposed rates, not final.)

- Free: $0 a month. Every feature, no card. 200 GB of cache downloads a month; 2M cache requests a month; 50 GB of storage (14-day window); Uploads free.
- Team: $0.05 per GB downloaded. Pay as you go beyond the free allowance. $0.005 per 1,000 requests beyond the allowance; Extra storage $0.05 per GB-month; Uploads free; Set a monthly budget; the cache stops at it. Xcode then compiles as usual: no failed builds, no surprise bill..
- Open source: $0 public repositories. Free for public repositories. No download or request limits; Storage up to 50 GB.
- Enterprise: Larger teams and custom terms: talk to us.
- On every plan, unlimited: Test selection, Test-result caching, CI reports, Crash symbolication, MCP server, Unlimited seats, repositories and Macs.
- Free during beta. Beta accounts get 3 months free after billing starts, and these rates locked for 24 months.
- No waitlist: sign in and the free tier is yours.

## Docs

- [Set up Warmbuild](https://warmbuild.dev/docs/): the full setup on one page
- [Before you start](https://warmbuild.dev/docs/#start): GitHub App, approval, Xcode version
- [CI: the GitHub Action](https://warmbuild.dev/docs/#ci)
- [Mac: the CLI](https://warmbuild.dev/docs/#mac)
- [Coding agents: the skill](https://warmbuild.dev/docs/#agents)
- [MCP server](https://warmbuild.dev/docs/#mcp): agents without a shell
- [CI report](https://warmbuild.dev/docs/#report), [Test selection](https://warmbuild.dev/docs/#selection), [Test results cache](https://warmbuild.dev/docs/#test-cache), [Crashes](https://warmbuild.dev/docs/#crashes)
- [Write rules](https://warmbuild.dev/docs/#rules), [Security and privacy](https://warmbuild.dev/docs/#security), [Troubleshooting](https://warmbuild.dev/docs/#trouble)
- [Guides](https://warmbuild.dev/guides/): [Xcode 26 compilation caching on GitHub Actions](https://warmbuild.dev/guides/xcode-26-compilation-caching/), [Why caching DerivedData with actions/cache doesn't speed up Xcode builds](https://warmbuild.dev/guides/deriveddata-actions-cache/), [What macOS runner minutes cost on GitHub Actions](https://warmbuild.dev/guides/macos-runner-cost/), [Warm Xcode builds for coding agents](https://warmbuild.dev/guides/xcode-builds-for-coding-agents/)
- [Case note: billet](https://warmbuild.dev/docs/#case-billet): one measured app
- [GitHub Action repository](https://github.com/warmbuild/action)
- [Full text for agents](https://warmbuild.dev/llms-full.txt)