# Auth0

> Learn how to track lead conversion events with Auth0 and Dub

import LeadsIntro from "/snippets/leads-intro.mdx";
import ConversionTrackingPrerequisites from "/snippets/conversion-tracking-prerequisites.mdx";
import LeadAttributes from "/snippets/lead-attributes.mdx";
import LeadsOutro from "/snippets/leads-outro.mdx";

<LeadsIntro />

In this guide, we will be focusing on tracking new user sign-ups for a SaaS application that uses Auth0 for user authentication.

<ConversionTrackingPrerequisites />

## Configure Auth0

Next, configure Auth0 to track lead conversion events.

Here's how it works in a nutshell:

1. In the sign in `afterCallback` function, check if the user is a new sign up.
2. If the user is a new sign up, check if the `dub_id` cookie is present.
3. If the `dub_id` cookie is present, send a lead event to Dub using `dub.track.lead`
4. Delete the `dub_id` cookie.

```typescript app/api/auth/[auth0]/route.js
import { handleAuth, handleCallback, type Session } from "@auth0/nextjs-auth0";
import { cookies } from "next/headers";
import { dub } from "@/lib/dub";

const afterCallback = async (req: Request, session: Session) => {
  const userExists = await getUser(session.user.email);

  if (!userExists) {
    createUser(session.user);
    // check if dub_id cookie is present
    const clickId = cookies().get("dub_id")?.value;
    if (clickId) {
      // send lead event to Dub
      await dub.track.lead({
        clickId,
        eventName: "Sign Up",
        customerExternalId: session.user.id,
        customerName: session.user.name,
        customerEmail: session.user.email,
        customerAvatar: session.user.image,
      });
      // delete the dub_id cookie
      cookies().set("dub_id", "", {
        expires: new Date(0),
      });
    }
    return session;
  }
};

export default handleAuth({
  callback: handleCallback({ afterCallback }),
});
```

<LeadAttributes />

<LeadsOutro />