nPowerAPIv2.py

#!/usr/bin/env python

import requests
import base64
import datetime
import json

# Fill your credentials in the authentication payload
payload = {
'userid':'',
'password':''
}

# API authentication header is your username in b64
cookieName = base64.b64encode(str.encode(payload['userid'])).decode().strip('=')

today = datetime.datetime.today()
# Download readings for the last 180 days
start_period = today - datetime.timedelta(days=180)

headers =  {
    'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.116 Safari/537.36',
}

session = requests.Session()
login = session.post('https://www.npower.com/at_home/applications/npower.web.login/api/session', data=payload, headers=headers)
config = session.get('https://www.npower.com/apps/config.json', headers=headers, cookies=login.cookies)
headers['Authorization'] = login.cookies[cookieName]

apilogin = session.get('https://api2.npower.com/authenticate/check', headers=headers)
contract = session.get('https://api2.npower.com/contractaccount', headers=headers)
contract_id = contract.json()[0]['Number']

info_customer = session.get('https://api2.npower.com/customer/{}'.format(contract_id), headers=headers)
user_detail = info_customer.json()
print('Hi {} {}, customer number {}'.format(user_detail[0]['Firstname'], 
        user_detail[0]['Lastname'], user_detail[0]['BPN'],))

readings = session.get('https://api2.npower.com/usage/{}?from={}&to={}'.format(contract_id, 
                        start_period.strftime('%Y-%m-%d'), today.strftime('%Y-%m-%d')), headers=headers) 
meter_readings = readings.json()

for meter in meter_readings:
    print('Contract: {}, Meter: {}'.format(meter['ContractNumber'], meter['SerialNumber']))
    for read in meter['MeterReads']:
        print('Date: {}, Type: {}, Read: {}, Plausible: {}'.format(read['ReadingDate'], 
                read['ReadingType'], read['Reading'], read['IsPlausible']))

meter_info = session.get('https://api2.npower.com/usage/{}/meterinformation'.format(contract_id), headers=headers) 
meter_list = meter_info.json()

for meter in meter_list['MeterInformations']:
    print('Contract: {}, Meter: {}, Fuel: {} MPXN: {}'.format(meter['ContractNo'], 
            meter['SerialNo'], meter['FuelType'], meter['MPXN']))