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customizing_to_json_example

💡 Customize to_json for Selective Attributes​

Rails’ built‑in to_json lets you filter out sensitive fields and include related objects without writing manual loops. You can pass :only, :except and :include options to tailor the JSON payload to your API’s needs.

# Fetch a user and only serialize id, name, email, and their posts' titles
user = User.find(1)
json = user.to_json(
  only: [:id, :name, :email],
  include: {
    posts: { only: [:id, :title] }
  }
)
puts json