Using New envato API to verify product purchase

[requireonce]

I am creating a new app to verify purchse using new api by envato.I have registered a new app on build.envato.com
below is the screenshot

First of all i have made a request on :https://api.envato.com/authorization?response_type=code&client_id=[CLIENT ID]&redirect_uri=[REDIRECT URI]

after permission user goes to [REDIRECT URI] and there i have to process the code.

According to envato API, on redirect page i will have to POST e request on:

POST https://api.envato.com/token grant_type=authorization_code& code=[CODE]& client_id=[CLIENT_ID]& client_secret=[CLIENT_SECRET]

My question is : where i can find [CLIENT_SECRET] and how i make this request in php

[baileyherbert]

The client secret is provided to you when you first register your new app. It is only shown to you once for security purposes, and you must copy and save it somewhere on your end.

Here is what it looks like (in this case my client secret is that CztSTwRXLI0… string):

Cheers!