To hook into the user registration process in Drupal 8 (and 9/10+), you typically use entity hooks since users are treated as content entities. 🛠️ Recommended Hooks
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Use this for actions that require the new User ID, like sending a custom welcome email or creating related profile entries. Modifies the registration form . drupal-8-user-register-hook
The most effective way to intercept or modify user data during registration is through the following hooks: Usage Note Runs before the user is saved.
Use this to add custom fields or validation logic (e.g., matching a secondary database). 💻 Code Example: hook_user_presave To hook into the user registration process in
This is the standard approach to identify a vs. an existing user being updated.
For cleaner, decoupled code, consider Symfony Event Subscribers if you are using the Hook Event Dispatcher module. The most effective way to intercept or modify
If you need to stop registration based on custom business logic (e.g., checking an external blacklist), use a custom validation handler via hook_form_alter .