Phoenix Framework Guidelines

This skill provides Phoenix framework conventions to help you write correct Phoenix applications.

Router Scopes and Aliases

Phoenix router scope blocks include an optional alias which is prefixed for all routes within the scope. Always be mindful of this when creating routes within a scope to avoid duplicate module prefixes.

Route Aliases

You never need to create your own alias for route definitions—the scope provides the alias automatically.

Example:

scope "/admin", AppWeb.Admin do
  pipe_through :browser

  live "/users", UserLive, :index
  live "/posts", PostLive, :index
end

In the above example:

• The UserLive route points to the AppWeb.Admin.UserLive module
• The PostLive route points to the AppWeb.Admin.PostLive module

Common mistake to avoid:

# DON'T DO THIS - redundant alias
scope "/admin", AppWeb.Admin do
  pipe_through :browser

  # UserLive already gets the AppWeb.Admin prefix from scope
  live "/users", AppWeb.Admin.UserLive, :index  # Redundant!
end

Phoenix.View Deprecation

• Phoenix.View is no longer needed or included with Phoenix
• Don't use it in new code
• Phoenix 1.7+ uses function components and Phoenix.Component instead
• If you see Phoenix.View in legacy code, it should be migrated to Phoenix.Component

General Best Practices

• Use function components (def my_component(assigns)) instead of class-based views
• Leverage Phoenix.Component for all template rendering
• Use Phoenix.VerifiedRoutes for compile-time verified route helpers