Moving from Railway, Render or Heroku

1. The app

• Deploy the same repository with New, Website or app. Most apps build as they are: Railpack works like Railway's Nixpacks and Railpack, and Heroku's and Render's buildpacks.
• Heroku: put the web: line from your Procfile in Start command, and a release: line in Pre-deploy command. Workers are their own apps with their own start command.
• Render: a Dockerfile service builds the same here; set the Dockerfile path in Settings if it isn't in the root.
• Listen on PORT, as on the others.

2. Variables

Copy them as a .env file (Railway: Raw Editor; Render: Environment, then each value; Heroku: heroku config -s) and paste it into the app's Variables tab. Swap other platforms' references for ours, such as ${{postgres.DATABASE_URL}}.

3. The database

Make the same engine here, then copy the data across while the old app is stopped, so nothing is lost:

# PostgreSQL: dump from the old database
pg_dump --no-owner --format=custom "$OLD_DATABASE_URL" > data.dump

# open the new one locally, then load it
wattle db proxy postgres --port 6543
pg_restore --no-owner --dbname "postgresql://USER:PASSWORD@localhost:6543/DATABASE" data.dump

The Connect tab shows the user, password and database name. For MySQL and MariaDB, use mysqldump and mysql the same way.

4. The domain

Add your domain in the app's Domains tab and make its records. When the certificate is active, move the CNAME from the old platform to ours. Keep the old app until traffic has moved.