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A deploy link lets a project author add a button to a README. A visitor who clicks it picks their own server (remembered in their browser) and lands on that server’s create-app form with the details filled in. Nothing is created until the visitor reviews the form and presses Deploy.

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URL scheme

Rules the form enforces:
  • Env values are never accepted from a link, only the names. The visitor types each value, and it is stored as a secret.
  • A parameter that fails validation is ignored, and a banner names every ignored parameter. Unknown parameters are ignored the same way.
  • The form shows “Prefilled from a link: review before deploying” and names the source host when source is valid.
  • If the link has no valid image, the regular new app wizard opens with the banner above it.

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Launcher page

Most READMEs should link to the launcher, because the author does not know the visitor’s server:
The launcher is a static page with a small script. It asks for the visitor’s server address once, stores it in localStorage in that browser only, validates that it is an http or https address without a username or password, then redirects to <server>/apps/new?deploy=1&... carrying the same parameters. It makes no external requests and has no tracking. It does not add deploy=1 to the link you write, the launcher does that.

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Badge

The badge is a flat SVG that reads on light and dark backgrounds:
Markdown for a README, using a real public image (traefik/whoami, port 80, health path /health):
Percent-encode : / and , inside parameter values as shown. For a project that needs secrets, add env=API_KEY,DATABASE_URL.
It validates the same rules as the form and prints the launcher link and the README Markdown. Add --server https://levelrail.example.com to also print the direct link for one specific server, or --launcher URL to point at a self-hosted copy of the launcher. See the CLI reference.

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Self-hosting the launcher

deploy.html and deploy.js are plain static files under docs/public. Copy both, plus badges/, to any static host and pass that host to --launcher.
Last modified on October 12, 2026