I answered a thread about integrating InvoiceNinja in a Laravel application 2 days ago:
But in summary InvoiceNinja SDK is distributed as a composer package, so you require it:
composer require invoiceninja/sdk-php
And use it as a normal class in your controllers:
<?php
use InvoiceNinja\Config as NinjaConfig;
use InvoiceNinja\Models\Client;
use Illuminate\Support\Facades\Route;
Route::get('/', function () {
NinjaConfig::setURL('https://ninja.dev/api/v1');
NinjaConfig::setToken('Your InvoiceNinja API token');
$client = Client::find(1);
return $client;
});
In the thread linked above I talked with its OP around setting the token in only one place, but the SDK usage is basically done through InvoiceNinja SDK's classes.
Hope it helps.