To get an oauth access token or refresh token from the TD Ameritrade API in Python, you may try to use normal query parameters like the following:
r = requests.post(
f'https://api.tdameritrade.com/v1/oauth2/token?grant_type=refresh_token&refresh_token={refresh_token}&access_type=&code=&client_id=MYAPIKEY@AMER.OAUTHAP&redirect_url=http://localhost',
}
)
However, this will result in the following error:
{'error': 'The API key in request is either null or blank or invalid.'}
Instead of using query parameters, use the data argument, which will submit it as x-www-form-urlencoded form data:
r = requests.post(
'https://api.tdameritrade.com/v1/oauth2/token',
data={
'grant_type': 'refresh_token',
'refresh_token': refresh_token,
'client_id': 'MYAPIKEY@AMER.OAUTHAP',
}
)