How to get your TDAmeritrade API credentials

APIKEY

You can get your apikey here.

Click on My Apps

Click on your app.

Click on keys

You should see your Consumer key there.

In your post request you should set apikey equal to that value.

ACCOUNT ID

First go here.

Click My Account

Scroll down to your account number, it should come just before:

And just after:

Go here for a guide on how to pass that value. Currently you include the account number in the path.