> ## Documentation Index
> Fetch the complete documentation index at: https://docs-dev-actions-triggers-reorg.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Actions Reference Overview

> Reference the event and api objects available to Auth0 Actions for each trigger, detailing the transaction data you can read and the methods you can call from your custom code.

Every Auth0 Action receives two objects when its trigger fires:

* The **event object** is read-only transaction context: details about the user, request, client, tenant, and connection at the moment the trigger fired.
* The **api object** exposes the methods your Action can call to change the outcome of the transaction, such as denying access, adding token claims, triggering challenges, or caching data.

The objects available differ per trigger. Select a trigger below to explore its event and api object reference. To learn when each trigger fires and how to attach Actions to it, read [Explore Triggers](/docs/customize/actions/explore-triggers).

## Triggers

| Trigger                       | Reference                                                                                                                                                                                                                                           | Fires...                                                                                                                                                                  |
| ----------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Credentials Exchange          | [Event object](/docs/customize/actions/reference/credentials-exchange/credentials-exchange-event-object) · [API object](/docs/customize/actions/reference/credentials-exchange/credentials-exchange-api-object)                                     | During a machine-to-machine Client Credentials exchange, before the access token is issued.                                                                               |
| Custom Phone Provider         | [Event object](/docs/customize/actions/reference/custom-phone-provider/custom-phone-provider-event-object) · [API object](/docs/customize/actions/reference/custom-phone-provider/custom-phone-provider-api-object)                                 | When Auth0 sends a phone message through a [custom phone provider](/docs/customize/phone-messages/configure-phone-messaging-providers/configure-a-custom-phone-provider). |
| Custom Email Provider         | [Event object](/docs/customize/actions/reference/custom-email-provider/custom-email-provider-event-object) · [API object](/docs/customize/actions/reference/custom-email-provider/custom-email-provider-api-object)                                 | When Auth0 sends an email through a [custom email provider](/docs/customize/email/smtp-email-providers/custom).                                                           |
| Custom Token Exchange         | [Event object](/docs/customize/actions/reference/custom-token-exchange/custom-token-exchange-event-object) · [API object](/docs/customize/actions/reference/custom-token-exchange/custom-token-exchange-api-object)                                 | During a custom token exchange request, when an external subject token is exchanged for Auth0 tokens.                                                                     |
| Event Stream                  | [Event object](/docs/customize/actions/reference/event-stream/event-stream-event-object) · [API object](/docs/customize/actions/reference/event-stream/event-stream-api-object)                                                                     | Asynchronously when a subscribed Event Type occurs on an Event Stream.                                                                                                    |
| Password Reset Post Challenge | [Event object](/docs/customize/actions/reference/password-reset-post-challenge/password-reset-post-challenge-event-object) · [API object](/docs/customize/actions/reference/password-reset-post-challenge/password-reset-post-challenge-api-object) | After the first password-reset challenge is completed and before the password is reset.                                                                                   |
| Post User Registration        | [Event object](/docs/customize/actions/reference/post-user-registration/post-user-registration-event-object) · [API object](/docs/customize/actions/reference/post-user-registration/post-user-registration-api-object)                             | Asynchronously after a user is added to a database or passwordless connection.                                                                                            |
| Post Login                    | [Event object](/docs/customize/actions/reference/post-login/post-login-event-object) · [API object](/docs/customize/actions/reference/post-login/post-login-api-object)                                                                             | After a user is authenticated but before a token is issued.                                                                                                               |
| Post Change Password          | [Event object](/docs/customize/actions/reference/post-change-password/post-change-password-event-object) · [API object](/docs/customize/actions/reference/post-change-password/post-change-password-api-object)                                     | After a user's password is changed or reset.                                                                                                                              |
| Pre User Registration         | [Event object](/docs/customize/actions/reference/pre-user-registration/pre-user-registration-event-object) · [API object](/docs/customize/actions/reference/pre-user-registration/pre-user-registration-api-object)                                 | Before a user is created in a database or passwordless connection.                                                                                                        |
| Send Phone Message            | [Event object](/docs/customize/actions/reference/send-phone-message/send-phone-message-event-object) · [API object](/docs/customize/actions/reference/send-phone-message/send-phone-message-api-object)                                             | When a custom provider sends the MFA enrollment and challenge phone messages.                                                                                             |

## Resources

| Read...                                                                    | To learn...                                                            |
| -------------------------------------------------------------------------- | ---------------------------------------------------------------------- |
| [Explore Triggers](/docs/customize/actions/explore-triggers)               | When each trigger fires and how Actions attach to it.                  |
| [Write Your First Action](/docs/customize/actions/write-your-first-action) | How to build, test, and deploy an Action end to end.                   |
| [Actions Limitations](/docs/customize/actions/limitations)                 | The size, execution, and rate limit constraints that apply to Actions. |