Do you need help on the registration form, or are you looking to redirect users after they sign up?
This is the standard approach to identify a vs. an existing user being updated.
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. drupal-8-user-register-hook
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
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 . Do you need help on the registration form,
Inside presave , always call $user->isNew() to ensure your code only runs during initial registration rather than every time a profile is updated.
Use this to add custom fields or validation logic (e.g., matching a secondary database). 💻 Code Example: hook_user_presave The most effective way to intercept or modify
Best for modifying data (e.g., adding a default role) before it hits the database. Runs after the user is created.