To find the Application ID and the Application secret, please navigate to menu "Applications".
The very first row contains the information needed.
To reveal the Application secret (which is your password) you have to click on the small lock.
By clicking on the small locker next to Application secret label, you will be prompted to fill in your password:
After filling in your password and pressing <Yes, show secret> button, you will be able to see your Application secret and use it as password.
Now that you have your token, you can start sending!
All your JSON posts should work as expected.
Detailed information on properties is available in the API documentation
Updated over 2 years ago