{
  "id": 1544107,
  "title": "Rails Routing & APIs: What Actually Happens Between the URL and Your Controller",
  "url": "https://urgent.news/2026/08/17/rails-routing-apis-what-actually-happens-between-the-url-and-your",
  "topic": "tech",
  "section": "Tech",
  "published": "2026-08-17T18:41:58.000Z",
  "source": {
    "name": "Dev.to",
    "slug": "dev-to",
    "url": "https://dev.to/lucasldemello/rails-routing-apis-what-actually-happens-between-the-url-and-your-controller-4elj"
  },
  "original_language": "en",
  "account": "When starting to learn about APIs more seriously, the author discovered a gap in their understanding of how Rails routing and APIs work together. They knew how to create a Rails API and write the necessary routes, but they weren't always able to explain the reasoning behind the functionality.\n\nRouting in Rails is the process that connects a URL to specific code within an application. This occurs in the routes.rb file. For example, a simple route could be defined as `get \"/about\", to: \"pages#about\"`. In this case, when someone makes a GET request to \"/about\", Rails knows to call the `PagesController#about` method.\n\nAs Rails becomes more complex, it introduces RESTful routes. The `resources` method automates the generation of conventional CRUD routes for a resource. For instance, using `resources :products` automatically generates routes for common actions such as listing, showing, creating, updating, and deleting products.\n\nThe distinction between `resource` and `resources` is also essential. A `resource` represents a single resource (e.g., `resource :profile`), while `resources` represents a collection of resources (e.g., `resources :products`). This difference affects the generated routes—`resource` does not create an index route, while `resources` automatically generates an index route for listing resources.\n\nAdding explicit `only` or `except` options allows for fine-tuning the exposed API endpoints. For example, `resources :products, only: [:index, :show]` only generates routes for listing and showing products, excluding other CRUD actions. This is particularly useful when designing an API because it clarifies the available actions for clients.\n\nNested resources illustrate relationships between resources. For instance, `resources :posts do resources :comments end` generates routes like `/posts/:post_id/comments` and `/posts/:post_id/comments/:id`. This explicit representation of relationships in the URL improves clarity and organization.\n\nWhen building an API, it's common to separate web controllers from API controllers. Rails supports namespaces for this purpose, allowing the creation of a separate namespace for the API. For example, `namespace :api, defaults: { format: :json } do namespace :v1 do resources :products end end` creates an API namespace with a versioning scheme (e.g., `/api/v1/products`). This approach enables multiple versions of the API to coexist without breaking existing clients.\n\nThe concept of REST, which stands for Representational State Transfer, is a more nuanced architectural style based on six constraints outlined by Roy Fielding. While using JSON and HTTP verbs can simplify some aspects of API design, REST encompasses more than just these elements. The key is understanding the constraints and applying them appropriately to achieve a well-structured, stateless, and scalable API design.",
  "summary": "When I started studying APIs more seriously, I realized there was a problem with the way I was learning. I knew how to create a Rails API. I knew how to write: resources :products I knew what GET , POST , PATCH and DELETE were supposed to do. But I wasn't always able to explain why things worked the way they did. So I decided to go one step back and review the fundamentals: routing, HTTP, REST…",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}