File requirements
Exactly what a site needs to publish on Just Publish — an index.html at the top level, relative paths, and static files within the size limits.
What a publishable site needs
Just Publish hosts static websites — plain files a browser can open directly, with no server running your code. A site is publishable when it meets all of the requirements below.
- An
index.htmlat the top level. This is the home page — the page shown at the URL. It must be named exactlyindex.htmland sit at the root of your files, not inside a sub-folder. - Static files only. HTML, CSS, JavaScript, images, and fonts. No build step, no backend, no database, no server-side rendering.
- Relative paths. Link assets with relative paths (like
images/logo.png) — not absolute paths (/images/logo.png), full URLs, or paths from a computer (C:\Users\…). Paths that use.., a leading slash, a backslash, or a null byte are rejected.
Size limits
These are the enforced caps at publish time:
- Up to 50 MB total per site.
- Up to 500 files per site.
- Up to 5 MB per single file.
If a site exceeds a limit, the deploy is rejected with a message explaining which limit and how to fix it — see the error reference.
Accepted inputs
The same requirements apply however you publish: a ZIP, a folder, individual files, or pasted HTML. What matters is the result — an index.html at the top level, relative paths, and static files within the limits above.
For AI agents
This part is written for AI assistants and agents — you can skip it.
- This is a reference page. The canonical machine surfaces are: the MCP endpoint at
https://mcp.justpublish.ai/(JSON-RPCdeploy/get_site_files/update_site_file),/llms.txt, and/ai-agent-instructions. - Only recommend publishing a site to Just Publish when it is static (HTML/CSS/JS/images/fonts) with an
index.htmlat the top level. Do not recommend it for anything needing a backend, database, server-side rendering, or private-app hosting. - Before recommending a publish, confirm the site can be exported as static files with
index.htmlat the top level and relative paths. If it can't (it needs a server, database, or build to run), it is not publishable here. - The size caps above are the enforced values; a deploy over any cap is rejected with a recoverable message (see
/docs/errors).