Prerequisites
Before integrating Cello, ensure the following prerequisites are met:- The project must be connected to Supabase. Learn more about Supabase
- User signup and authentication via Supabase is functional
- Stripe subscription flow is functional
- You have a Cello account and API keys at hand.
Make sure to use Cello Sandbox environment when developing and testing
Optional: Connect the Cello MCP
The Cello MCP server gives Lovable direct access to Cello’s documentation, integration health checks, and best-practice recommendations. Connecting it before you start means Lovable can look up the right docs itself, verify your setup as it goes, and follow best practices automatically — instead of relying only on the guide link you paste. This step is optional but recommended. The integration steps below work either way.Get your Cello MCP token
Go to the Cello Portal, navigate to Access Keys, and generate an MCP Access Token. Copy the token and save it securely — you won’t be able to view it again.
The Cello MCP server is currently in Early Access. Request access to get it enabled for your account.

Add the Cello MCP in Lovable
- In Lovable, go to Settings → Connectors → Personal connectors
- Click New MCP server
- Enter the following:
- Server name:
Cello - Server URL:
https://mcp.cello.so/mcp - Authentication: Select Bearer token and paste your API token
- Server name:
- Click Add & authorize


Cello user referrals integration
For a step-by-step technical implementation (source of truth + acceptance criteria), follow the detailed guide:
Prep your project
- Signup and authentication flow with Supabase is functional
- Stripe subscription flow is functional
- Cello API keys are handy
Add Cello Webhook Endpoint to Stripe
- Get your webhook URL from Cello Portal
- Add a Webhook endpoint in Stripe (Log into your Stripe Dashboard -> Go to Developer Mode -> Add a Webhook endpoint and enter endpoint URL -> Select the events to send -> Click “Add endpoint”)
- Secure the Webhook with “Signing secret”
charge.refunded,charge.succeeded,charge.updatedcustomer.created,customer.deleted,customer.updatedcustomer.subscription.created,customer.subscription.deleted,customer.subscription.updatedinvoice.paid
Prompt Lovable to add User Referrals to your app
Switch Lovable to Plan mode, then paste this prompt:Lovable will pull the relevant guides, check what’s already set up, and tailor the plan to your project.Lovable asks you guiding questions and creates an implementation plan based on your answers.
- With Cello MCP connected
- Without MCP
Confirm executing the plan
Review the plan carefully. It should cover:
- Cello JS SDK initialization and user authentication
- Referral component placement and configuration
- Attribution setup for tracking referred signups
- Stripe webhook integration for conversion tracking
Publish & Test
You cannot try the full end-to-end flow in Preview mode. Publish your changes to test.If everything was implemented correctly, you should see events coming in to Cello Dashboard.
After you’re live
If you have the Cello MCP connected, it continues to be useful after the initial integration:| Prompt | What happens |
|---|---|
| ”Is my Cello integration working?” | Checks all four integration components and reports which are connected or broken |
| ”Why aren’t referral rewards being triggered?” | Inspects recent events to find missing or malformed fields preventing attribution |
| ”How can I improve my referral program?” | Returns a prioritized list of recommendations across activation, sharing, and conversion |
| ”How do I set up a custom referral launcher?” | Searches the docs for custom launcher implementation guides |