How to Detect What Technology Stack Any Website Is Using (Programmatically)

You're doing competitive analysis on a competitor's site. Or you're qualifying sales leads and need to know which prospects run Shopify. Or you're on a security audit and need to confirm which CMS versions are deployed across a client's domain portfolio. In all of these cases, you need to answer the same question: what technology is this website actually running? This post walks through how to detect website tech stacks — from manual approaches using raw HTTP inspection, to automated detection using an API. By the end you'll have working Python code for both approaches. The Manual Approach: What Browsers Know That You Don't See Before reaching for any tool, it helps to understand what signals technology leaves behind. There are four main layers to inspect. 1. HTTP Response Headers Servers often leak stack information directly in response headers. A quick curl -I can reveal a surprising amount: import httpx def check_headers ( url : str ) -> dict : resp = httpx . get ( url , follow_redi