This is a real gotcha in Coolify, and it cost significant debugging time when setting up this wiki itself - worth a dedicated page.
For a normal Application, there's a domain field right on its settings page. For a Docker Compose service (any one-click install, like Wiki.js, or a custom multi-container compose file), that field often just isn't visible anywhere obvious in the service overview or the general Environment Variables tab. It's not broken - it's just surfaced somewhere unexpected.
wikijs and postgres).wikijs), not the service overview.sslip.io address.domain:internal-port format - e.g. wiki.magnusschult.de:3000 - not just the bare domain. Leaving off the port triggers a confirmation dialog; click "Cancel - Keep Port" and re-enter it with the port suffix to avoid that warning.Coolify auto-generates SERVICE_FQDN_* / SERVICE_URL_* variables per compose service, and it's tempting to edit those directly via the API or UI. Don't - they're read-only reflections of internal state. Writing to them does not change the actual Traefik routing; only the Domains field on the sub-service's own page does that.