> ## Documentation Index
> Fetch the complete documentation index at: https://docs.cello.so/llms.txt
> Use this file to discover all available pages before exploring further.

# Cello + Codex integration

> How to add user referrals to your app using Cello with Codex

Codex can implement Cello user referrals end-to-end if you give it the **right guidance** and force it to create a plan before coding.

## Prerequisites

Before integrating Cello, ensure the following prerequisites are met:

* Signup and authentication flow with a database to store user records is functional.
* Stripe or Chargebee subscription flow is functional.
* You have a Cello account and API keys at hand.

<Note>
  Make sure to use Cello **Sandbox environment** when developing and testing
</Note>

## Cello user referrals integration (Coding-agent flow)

<Steps>
  <Step title="Step 1">
    **Connect the Cello MCP**

    Add the Cello MCP server from the terminal:

    ```bash theme={null}
    codex mcp add cello-so --url https://mcp.cello.so/mcp
    ```

    Authenticate via the Cello Portal when prompted.
  </Step>

  <Step title="Step 2">
    **Add Cello Integration Guide Skill**

    Download the skill into your repo's skills folder:

    ```bash theme={null}
    mkdir -p .agents/skills/cello-get-integration-guide
    curl -o .agents/skills/cello-get-integration-guide/SKILL.md \
      https://raw.githubusercontent.com/getcello/cello-cursor-plugin/main/skills/cello-get-integration-guide/SKILL.md
    ```

    Restart Codex so it picks up the new skill.

    <Tip>
      You can also install it at the user level (`$HOME/.agents/skills`) so it's available across all your projects, or at the admin level (`/etc/codex/skills`) for your whole org.
    </Tip>
  </Step>

  <Step title="Step 3">
    **Integrate Cello**

    * Use the skill to get a tailored integration guide for Cello
    * Codex will ask you questions that cannot be answered automatically
  </Step>

  <Step title="Step 4">
    **Confirm executing the plan**

    * Review the plan carefully. If it looks correct, tell Codex to proceed and start implementing it.
  </Step>

  <Step title="Step 5">
    **Publish & Test**

    * Run your app and test the end-to-end flow. If everything was implemented correctly,
    * You should see events coming into the [Cello Dashboard](https://portal.cello.so/dashboard/referrer).
    * Or you can validate your integration by using the Cello MCP tools and prompt "Is my Cello integration working?"
  </Step>
</Steps>

<Note>
  For a step-by-step technical implementation (source of truth + acceptance criteria), follow the detailed guide:

  * [React + Node.js Integration Guide](/resources/react-nodejs-integration)

  The guide uses React + Node.js as an example, but it can be any other combination - the steps stay the same.
</Note>