Geekflare is supported by our audience. We may earn affiliate commissions from buying links on this site.
In Development Last updated: August 12, 2020
Share on:
Invicti Web Application Security Scanner – the only solution that delivers automatic verification of vulnerabilities with Proof-Based Scanning™.

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


root@gf-lab:~# python3
{'http2': True}

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.

  • Chandan Kumar
    As the founder of Geekflare, I’ve helped millions to excel in the digital realm. Passionate about technology, I’m on a mission to explore the world and amplify growth for professionals and businesses alike.
Thanks to our Sponsors
More great readings on Development
Power Your Business
Some of the tools and services to help your business grow.
  • Invicti uses the Proof-Based Scanning™ to automatically verify the identified vulnerabilities and generate actionable results within just hours.
    Try Invicti
  • Web scraping, residential proxy, proxy manager, web unlocker, search engine crawler, and all you need to collect web data.
    Try Brightdata
  • is an all-in-one work OS to help you manage projects, tasks, work, sales, CRM, operations, workflows, and more.
    Try Monday
  • Intruder is an online vulnerability scanner that finds cyber security weaknesses in your infrastructure, to avoid costly data breaches.
    Try Intruder