An example of validing a license key using Python 3's standard library

license_key_validation.py

from urllib.request import Request, urlopen
import json
import sys

req = Request(
  'https://api.keygen.sh/v1/accounts/demo/licenses/actions/validate-key',
  method='POST',
  data=json.dumps({
    'meta': {
      'key': 'C1B6DE-39A6E3-DE1529-8559A0-4AF593-V3',
    }
  }).encode('ascii'),
  headers={
    'Content-type': 'application/json',
    'Accept': 'application/json',
  },
)

with urlopen(req) as response:
  validation = json.load(response)

  if validation['meta']['valid']:
    print('License is valid!')

    sys.exit(0)
  else:
    print('License is invalid: {constant}'.format(**validation['meta']))

    sys.exit(1)