---
title: Passing Device and Behavioral IDs to Auth0 at Login
slug: public-apis/passing-device-and-behavioral-ids-to-auth0-at-login
createdAt: 2026-11-02T15:08:19.733Z
---

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**Topic type: Task**

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**Purpose**: Passes the Accertify collector's device and behavioral IDs to Auth0 on the login redirect.

**Audience**: Front-end engineers who maintain the login page.

**Applies to**: Login screening with the Post Login Action, on login pages where the Accertify collector runs.

**Does not apply to**: Sign-up requests, which pass the IDs in `user_metadata`.
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Before your page redirects the user to the Auth0 `/authorize` endpoint, attach the collector's IDs as custom query parameters that start with `ext-`. The Action reads two of them on each login: `deviceTransactionID` and `ubaID`. Send ID references only. For the size and format limits, see [Limits for ext- Parameters in the Auth0 Login Redirect](docId\:wPjzSjrRQySPva4cK8SsV).

**To pass:**

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Call `window._bcn.snapshot()` and wait for the bundle it returns. Use it rather than the individual getters: `snapshot()` waits until the collector has finished and its callbacks have fired, so the IDs are complete.
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Read `deviceTransactionID` and `ubaID` from the bundle, and pass them as `ext-deviceTransactionID` and `ext-ubaID` in the authorization parameters of your login redirect. The following example uses `auth0-spa-js`:

```javascript
async function login() {
  const bundle = await window._bcn.snapshot();
  await loginWithRedirect({
    authorizationParams: {
      'ext-deviceTransactionID': bundle.deviceTransactionID,
      'ext-ubaID': bundle.ubaID,
    }
  });
}
```
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**Expected result:** Your `/authorize` request includes both `ext-deviceTransactionID` and `ext-ubaID`.

`ext-` parameters are a documented Auth0 feature, not a workaround. For more information, see Auth0's article [Limit of “ext-” Parameters on Universal Login Page](https://support.auth0.com/center/s/article/Limit-of-ext-parameters-on-universal-login-page).

For the full list of login fields that Accertify's API accepts, including these IDs, see [Accertify login fields reference](docId:0DG-4GT8p9N0pc25js9Z1).

## Next Steps

Continue with the Action install:

- **Install the Action:** [Installing the Accertify Account Protection Action](docId\:AHZKMD0Dk4OD4An5yy4Nx)



***

**See also**:

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:::LinkArrayItem
[Limits for ext- Parameters in the Auth0 Login Redirect](docId\:wPjzSjrRQySPva4cK8SsV)
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[Auth0 Overview](docId:83YMYFB8wEXwmkEtJe9gH)
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[Installing the Accertify Account Protection Action](docId\:AHZKMD0Dk4OD4An5yy4Nx)
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