Source: https://jessewaites.com/blog/post/using-uuids-as-primary-keys-in-rails-apps

# Using UUIDs as primary keys in Rails apps

*September 23, 2025*

If you are using UUIDs as primary keys in your Rails application, you may find it tedious to specify them in every single migration. Fortunately, Rails provides a clean way to set this configuration globally so that all new tables use UUIDs automatically.

By adding a simple generator configuration to your `config/application.rb`, Rails will handle the primary key type for you. Inside your application class, define:

```
config.generators do |g|
  g.orm :active_record, primary_key_type: :uuid
end

```

With this setting in place, any time you generate a new model, Rails will create migrations that use UUIDs as the default primary key. This eliminates repetitive setup and ensures consistency across your database schema. It's a small change that can save you time!