s = requests.Session() s.auth = ('user', 'pass') s.headers.update({'x-test': 'true'}) # both 'x-test' and 'x-test2' are sent s.get('https://httpbin.org/headers', headers={'x-test2': 'true'})
s = requests.Session() s.get('https://httpbin.org/cookies/set/sessioncookie/123456789') r = s.get('https://httpbin.org/cookies') print(r.text) # '{"cookies": {"sessioncookie": "123456789"}}'