supabase-cli/docs/supabase/link.md

supabase-link

Link your local development project to a hosted Supabase project.

PostgREST configurations are fetched from the Supabase platform and validated against your local configuration file.

Optionally, database settings can be validated if you provide a password. Your database password is saved in native credentials storage if available.

If you do not want to be prompted for the database password, such as in a CI environment, you may specify it explicitly via the SUPABASE_DB_PASSWORD environment variable.

Some commands like db dump, db push, and db pull require your project to be linked first.