Environment variables
More → Environment variables is the key/value list for this project. Values are available to preview and to the Cloud backend. Secrets are masked in the UI after save.
Add or edit
Create a key, paste the value, save. Update or delete from the same list.
Use this for public API keys you are comfortable exposing to the frontend (with the usual caveats), and for server-only names that endpoints/crons should read.
What not to store in the repo
Chat is instructed not to write PATs, service role keys, or function secrets into generated website files. If a secret leaked into code, rotate it, put the new value here (or on the endpoint env), and ask chat to remove it from the tree.
Cloud functions also get SUPABASE_URL / anon / service role injected when Cloud is on. You do not need to duplicate those unless you are pointing at a hosted Supabase integration instead.
vs Cloud endpoint env
Per-endpoint environment can be set when chat creates or updates a function. The More → Env list is the project-wide set. Prefer one place per secret so you are not debugging two sources.