Keys and MCP servers

Give the AI your API keys for any service and connect MCP servers, so it can work with Stripe, Firebase, OpenAI or your own API while it builds.

Keys let the AI work with any service you use — Stripe, OpenAI, Airtable, Firebase, your own API — not only the ones in the connector catalog. The AI uses a key by its name and never sees its value: ESTAGE fills the value in on its servers, sends it only to the hosts you list, and keeps it out of your site's code.

MCP servers give the AI a provider's own tools, such as Supabase's or Stripe's.

Both live in Settings → Connectors, above the connector catalog.

Adding a key

1. Open Settings → Connectors and select Add key in the Keys section.
2. Fill in Name, for example STRIPE_SECRET_KEY. Use capital letters, digits and underscores.
3. Paste the key into Value.
4. In Hosts, list where the key may be sent, separated by commas — for example api.stripe.com, or *.googleapis.com for a Google service account. Without a host, the AI can't use the key.
5. Optionally describe what it's for, then select Save key.

You can also paste a key in the chat, and the AI saves it as a key. Adding it in Settings is safer: a key pasted in the chat stays in the chat history.

To change a key, select Edit. Leave Value empty to keep the saved one. Delete removes the key, and anything the AI set up with it stops working.

Asking the AI to use a key

Ask in plain words, for example:

• "List my Stripe products with STRIPE_SECRET_KEY"
• "Read the users collection from Firestore with FIREBASE_SA" — for a Google service-account JSON saved as a key with the host *.googleapis.com
• "Create the products from this list in my store's API"

The AI calls the service while it builds — to read data, check what's there, or create what you asked for. It deletes data on the other side only after you say so.

Connecting an MCP server

1. Add the server's token under Keys, with the server's host — for Supabase, mcp.supabase.com.
2. In MCP servers, select Add server.
3. Fill in Name (for example supabase) and the server's URL.
4. In Headers, write the token by name: Authorization: Bearer {secret.SUPABASE_TOKEN}.
5. Select Save server.

The AI can use the server's tools from your next message. Select Turn off to pause a server without removing it. When a server has a read-only mode, prefer it — for Supabase, add ?read_only=true to the URL.

Things worth knowing

• Keys are per project. Another project doesn't see them.
• A key goes only to its hosts. Only you can add a host to a key, in Settings. The AI can add a new key you give it, or remove hosts.
• The AI never shows a value. If a service sends a key back in its answer, the AI sees the key's name in its place.