Python is fast and known for its performance and capabilities.

While working on the HTTP/2 test tool, I tried many options and found Python was fastest, more accurate, and lightweight. If you are developing something in-house to test if the site supports HTTP/2 or not, you may use the following code.

It works on Python 3.x.

import socket
import ssl
import csv
import argparse

from urllib.parse import urlparse


headers = {"user-agent": "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/71.0.3578.98 Safari/537.36"}

def check_http2(domain_name):
		HOST = urlparse(domain_name).netloc
		PORT = 443

		ctx = ssl.create_default_context()
		ctx.set_alpn_protocols(['h2', 'spdy/3', 'http/1.1'])

		conn = ctx.wrap_socket(
			socket.socket(socket.AF_INET, socket.SOCK_STREAM), server_hostname=HOST)
		conn.connect((HOST, PORT))

		pp = conn.selected_alpn_protocol()

		if pp == "h2":
			return {"http2": True}
			return {"http2": False}
	except Exception as e:

parser = argparse.ArgumentParser()
parser.add_argument("domain", help="display a square of a given number",
args = parser.parse_args()


To run the program, you can use the following syntax.

python3 $ $URL


[email protected]:~# python3
{'http2': True}
[email protected]:~#

You see the few lines of code to achieve. If you are looking to master in Python, then check out this Udemy course. And, to take advantage of H2 protocol, refer the following implementation guide.