# Serialize list of items with ActiveModel::Serializer

Most of the them, when working on Rails with ActiveModel::Serializer you will do something like this:

```ruby
render json: user, serializer: UserSerializer
```

Or if it's a list

```ruby
render json: users, each_serializer: UserSerializer
```

This way, Rails will take care of calling your serializer with the item or calling each item on the list with the serializer.

What happens if you want to manually call them inside a list? You can do

```ruby
render json: ActiveModel::Serializer::CollectionSerializer.new(
  users,
  serializer: UserSerializer
).as_json
```

This way you will tell `ActiveModel::Serializer` to call your serializer `UserSerializer` for a collection of items and use `users` as the data, so the gem will iterate the list of users and serialize them.