You can simply add any routes you want in your service provider's 'boot' method:

public function boot(){    $this->app['router']->get('my-route', 'MyVendor\Mypackage\MyController@action');}

If you want to have a kind of automatic prefix, that doesn't happen automatically, but it's not too hard to create one:

public function boot(){    $this->app['router']->group(['prefix' => 'my-module'], function ($router) {         $router->get('my-route', 'MyVendor\MyPackage\MyController@action');         $router->get('my-second-route', 'MyVendor\MyPackage\MyController@otherAction');    });}

A lot of people will have this prefix as a config variable so that developers can choose the prefix they want (if you do this remember to name your routes so you can refer to them easily):

public function boot(){    $this->app['router']->group(['prefix' => \Config::get('my-package::prefix')], function ($router) {         $router->get('my-route', 'MyVendor\MyPackage\MyController@action');         $router->get('my-second-route', 'MyVendor\MyPackage\MyController@otherAction');    });}

Just some theory

That's in fact pretty easy! When you think about it, Laravels routing layer is also just a component that is bound to Laravels container.

That allows us to grab it from there wherever we're accessing the container. Since you're trying to modify routes in a package, a great place to do it would be in your packages Service Provider.

Also, when doing that in a Service Provider you'll automatically have access to the app property (Your service provider is a child class of Laravels ServiceProvider class) and you can grab the router pretty easy!

Hands on code

<?php namespace My\Packages\Namespace;use Illuminate\Support\ServiceProvider;class MyPackageProvider extends ServiceProvider {    public function boot()    {        $this->app['router']->get('package-route', function(){            return "I just dynamically registered a route out of my package";        });         }}

That's the Service Provider of your package. The only thing the user will have to do is to add the Service Provider to his providers array in the config/app.php.

Be careful!

When a user has defined a route that is identically named as your dynamically added route, your route will be overwritten. Make sure that you're using some kind of route prefixes if you are dynamically adding routes.

Further Reading

Laravel Docs - IoC Container

I know I'm bit late but in Laravel 5.4 we can achieve something like this:

Step 1 Create your package and create service provider in it.

Step 2 Register your package service provider in laravel config app.

Step 3 Now create a sperate routes service provider which will contain following

namespace MyPackage\Providers;use App\Providers\RouteServiceProvider;use Illuminate\Support\Facades\Route;class MyPackageRouteServiceProvider extends RouteServiceProvider{    protected $namespace='MyPackage\Controllers';    public function boot()    {        parent::boot();    }    public function map()    {        $this->mapApiRoutes();        $this->mapWebRoutes();    }    protected function mapApiRoutes()    {        Route::prefix('Mypackage\api')            ->middleware('api')            ->namespace($this->namespace)            ->group(__DIR__ . '\..\Routes\api.php');    }    protected function mapWebRoutes()    {        Route::prefix('Mypackage')            ->middleware('web')            ->namespace($this->namespace)            ->group(__DIR__ . '\..\Routes\web.php');    }}

Note: I'm considering there is Routes Folder and contain web.php and api.php file. According to your question you want to load it dynamically you can have a constructor function and pass the package name, prefix and namespace as per your ease.

Step 4 Now the final step is registering the service provider you can call something like this in your package service provider:

public function boot(){    $this->app->register('Mypackage\Providers\MyPackageRouteServiceProvider');}

Hope this helps. Cheers