API versioning patterns in Laravel - Step-by-Step Execution

Concept Flow - API versioning patterns

Client sends API request

↓

Check version info in request

↓

URL

↓

Route request to correct versioned controller

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Process request and send response

The API receives a request, detects the version from URL, header, or query, then routes to the matching version controller to respond.

Execution Sample

Laravel

Route::prefix('api/v1')->group(function () {
    Route::get('/users', [UserControllerV1::class, 'index']);
});

Route::prefix('api/v2')->group(function () {
    Route::get('/users', [UserControllerV2::class, 'index']);
});

Defines two API versions using URL prefixing, routing requests to different controllers based on version.

Execution Table

Step	Request URL	Version Detected	Controller Called	Response Behavior
1	/api/v1/users	v1 (from URL prefix)	UserControllerV1@index	Returns user list in v1 format
2	/api/v2/users	v2 (from URL prefix)	UserControllerV2@index	Returns user list in v2 format with extra fields
3	/api/users?version=1	v1 (from query param)	UserControllerV1@index	Returns user list in v1 format
4	/api/users	default version (v1)	UserControllerV1@index	Returns user list in v1 format
5	/api/users	header X-API-Version: 2	UserControllerV2@index	Returns user list in v2 format
6	/api/v3/users	No route defined	404 Not Found	Error response - version not supported

💡 Requests stop after routing to the correct controller or returning error if version unsupported.

Variable Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	After Step 4	After Step 5	Final
version	null	v1	v2	v1	v1	v2	null
controller	null	UserControllerV1@index	UserControllerV2@index	UserControllerV1@index	UserControllerV1@index	UserControllerV2@index	null
response	null	v1 user list	v2 user list	v1 user list	v1 user list	v2 user list	error or user list

Key Moments - 3 Insights

How does Laravel know which API version to use when the version is in the URL?

Laravel uses route groups with prefixes like 'api/v1' or 'api/v2' to detect the version from the URL and route to the matching controller, as shown in execution_table rows 1 and 2.

What happens if the client does not specify a version in the request?

Laravel routes to a default version controller, often the first version, as shown in execution_table row 4 where no version is in URL or headers, so v1 controller is used.

Can API versioning be done using HTTP headers instead of URL?

Yes, Laravel can check headers like 'X-API-Version' to decide the version, routing accordingly as in execution_table row 5.

Visual Quiz - 3 Questions

Look at the execution table, which controller handles the request to '/api/v2/users'?

A UserControllerV1@index

B UserControllerV3@index

C UserControllerV2@index

D 404 Not Found

💡 Hint

Check the row where Request URL is '/api/v2/users' in the execution_table.

At which step does the request return a 404 error due to unsupported version?

A Step 3

B Step 6

C Step 4

D Step 1

💡 Hint

Look for the row with 'No route defined' in the Version Detected column.

If the client sends '/api/users' with header 'X-API-Version: 2', which version is used?

A v2

B v1

C default (v1)

D No version detected

💡 Hint

See the execution_table row where header 'X-API-Version: 2' is used.

Concept Snapshot

API versioning in Laravel routes requests based on version info.
Common patterns:
- URL prefix (e.g., /api/v1)
- Query parameter (e.g., ?version=1)
- HTTP header (e.g., X-API-Version)
Routes map to versioned controllers.
Default version used if none specified.

Full Transcript

API versioning patterns in Laravel help manage different versions of an API. The client sends a request with version info in the URL, query, or header. Laravel detects this version and routes the request to the matching controller. For example, URL prefixing uses route groups like 'api/v1' or 'api/v2' to separate versions. If no version is specified, a default version controller handles the request. This approach allows maintaining multiple API versions simultaneously and evolving the API without breaking existing clients.