Why request doesn't work with slash in the end of URL

In Controller I have this method:

Code:

public function webhook()
    {
        $request = \Config\Services::request();

        $hook_request = $request->getJSON();
        var_dump($hook_request);
        }

if I send request like http://localhost/controller/webhook - this works
If I send http://localhost/controller/webhook/ it's not worked
What is wrong?

What do you mean by "it's not worked"?
What happened?

ci-phpunit-test | CodeIgniter Testing Guide | CodeIgniter 3 to 4 Upgrade Helper

What do you mean by "it's not worked"?
What happened?

I send POST data.
when add slash in the end URL returns NULL

Are you by any chance using Postman for testing?

Are you by any chance using Postman for testing?

Yes, I use postman for testing API.
Is it reason of my problem?

He has such a bug when, depending on the presence or absence of a slash, he (I don’t remember exactly) either does not send data or uses the GET method instead of POST.

He has such a bug when, depending on the presence or absence of a slash, he (I don’t remember exactly) either does not send data or uses the GET method instead of POST.

Thank you!