It seems that Laravel 5 by default applies the CSRF filter to all non-get requests. This is OK for a form POST, but might be a problem to an API that POSTs DELETEs etc.
Go to app/Http/Middleware/VerifyCsrfToken.php and then enter your routes(for which you want to disable csrf token) in the $except array.
app/Http/Middleware/VerifyCsrfToken.php
for example:
class VerifyCsrfToken extends BaseVerifier { protected $except = [ '/register' ]; }