Tell your agent to build the site. Ship 100/100/100/100.
fastsite is a self-hosted publishing engine that speaks the Model Context Protocol. Point Claude, ChatGPT, or Codex at it and let them author, design, translate, and publish. What lands on your CDN is fully static HTML with zero JavaScript.
you › add a pricing page to acme, then publish
fastsite get_authoring_guide(site: "acme") ✓
fastsite create_page(slug: "pricing", status: "published")
fastsite publish_site(site: "acme") ✓
# build → 1 page written, 41 unchanged
# audit → 0 fails, 0 warnings, 0 KB JS
# commit → acme-dist@f3c81a2 → live in 4.1sBased on MCP
The agent is the interface.
Every capability in fastsite is exposed as a Model Context Protocol tool — creating pages, uploading media, editing the Twig shell, adding a locale, rolling back a revision, publishing. There is a dashboard, but you never have to open it.
Scopes are consented per capability, and which sites they apply to follows your own account — so an agent that can write your blog cannot touch your infrastructure. Every call is logged, every publish is one reviewable git commit.
- ✓ OAuth consent
- ✓ Per-scope control
- ✓ Audited tool calls
- ✓ One commit per publish
Author
Pages, posts, media, components and redirects — created and revised in place, sanitized on every ingest.
Shell
Templates and CSS tokens are files the agent can read and rewrite. Snapshot before, restore after.
Localise
Add a locale and published content plus UI strings are translated, with correct hreflang across the tree.
Publish
Incremental build, blocking audit, commit to your repo, live on the edge. Backups and rollback included.
Things people actually type
What you get
Content goes in. Static HTML comes out.
No page builder, no runtime, no database at the edge. The engine is the build step — your visitors only ever receive pre-rendered files.
MCP server
Native Model Context Protocol over HTTP. Any MCP client — Claude, ChatGPT, Codex, your own — authors and publishes with scoped consent.
REST API
A clean, scoped, idempotent JSON API. Everything the dashboard does, the API does, for pipelines that are not agents.
Webhooks
HMAC-signed inbound webhooks map any payload to a post, page, media import, or component. Wire it up and forget it.
Automatic images
Every upload becomes AVIF and WebP at five widths plus an OG crop — EXIF-stripped, dimensioned, lazy-loaded, alt text enforced.
Auto-translation
Add a locale and the engine translates published content and UI strings, emits per-language trees, and keeps them in sync.
Components
Author HTML fragments or React components. React is compiled to static markup at build time — interactive authoring, zero shipped JS.
Screenshots
A dashboard you can ignore.
Everything the agent does is visible, editable, and reversible by hand — content, media, the shell, the build log.
Sites overview — build status, locales, and last publish per site.
Shell editor — Twig templates and CSS tokens, versioned with restore.
Build audit — every rule that would cost a PageSpeed point, before it ships.
Install
Self-hosted, one compose file.
fastsite runs on your own box. Docker and a domain are the whole dependency list — the engine builds static output and pushes it to a git repo your CDN watches.
No vendor account, no per-seat pricing, no data leaving your infrastructure.
# clone, configure, run
git clone https://github.com/sitepointsystems/getfastsite_gnu.git
cd getfastsite_gnu && cp .env.example .env
docker compose up -d
# create the first admin account
docker compose exec app php bin/fastsite install \
--email=you@example.com --password='…'
# the dashboard and the MCP endpoint are now up
# https://your-host/ dashboard
# https://your-host/mcp MCP server
# https://your-host/api/v1 REST APIWorks with
Bring your own agent.
fastsite is a standard MCP server over HTTP. If your client speaks MCP, it can run your sites.
Claude
Add the server URL under connectors in Claude Desktop or on claude.ai, approve the scopes once, and author from chat.
ChatGPT
Register fastsite as a connector in developer mode and it becomes available as a tool inside any conversation.
Codex
Add the server to your Codex config and drive fastsite from the CLI or the desktop app alongside your repo.
Your own client
Standard MCP over HTTP with OAuth. If you would rather not use an agent at all, the REST API covers the same ground.
Why this exists
Publishing tooling kept getting heavier and more expensive, and then rented back to the people who depend on it.
fastsite is built by Lennart Øster, a Danish developer who has been writing software since 1995 and running it alone, on purpose, for the last fifteen years. The pattern is always the same: something in the stack is good but costly, so he builds the version he actually wants and gives it away.
That produced an open source consent platform and a CRM priced flat instead of per seat. fastsite is the same move applied to publishing.
No per-seat pricing
Not now, not when the cloud version arrives. Charging per login rations the tool inside the teams that need it most.
Self-hosting is first class
The free version is the whole engine, not a crippled tier. Your content and credentials stay on your hardware.
Open so it cannot be taken
GPL means no one — including the author — can close the project or pull it out from under you.
Weight is a bug
Zero shipped JavaScript is not a target you hit occasionally. The build refuses to publish a page that misses it.
Open source
GPL licensed. Yours to run, read, and fork.
fastsite is released under the GNU General Public License. Run it on your own hardware, audit every line, change what you need — and if you ship a modified version, share it back under the same terms.