In-house

Pacing TechStack

Type in a website address and it lists the tools and tracking running on it. A quick scan takes about 5 seconds, a complete one about 40.

Talk numbers Everything we built

Tech Stack Analysis7,000+ technologies checked

~~https://~~example-shop.co.ukAnalyse

42 technologies
9 categories
18s scan

ShShopfront CMSEcommerceHigh 96%
CfEdge networkCDNHigh 94%
TmTag managerTag managersHigh 91%
PxAd pixelAdvertisingMedium 64%
HmHeatmap scriptAnalyticsLow 38%

Live, in-house

This one is us: new business and audit. Before a pitch we need a straight answer to one question: what is on this site?

Guessing the CMS in a first meeting wastes the hour. A stack list isn't a plan either. We wanted the list out of the way, so the conversation can move on to tracking, consent and what we'd change.

What it does

Scan a URL against a maintained set of definitions. Show names, categories, versions where we can see them, and a confidence score. Save the company so we can search it later. Export JSON, CSV or PDF when a report needs to leave the tool.

Competitor URLs go through the same scan, and the same API is there for n8n when a new client lands.

Detection: URL patterns, HTML, headers, scripts, and meta tags. Cookie detection isn't built yet.
Companies database: every scan is saved, so we can look a domain up later instead of running it again.
Live progress: you see each stage as it happens, not a spinner.

How it works

Definitions come from enthec/webappanalyzer, an open-source set that's still being maintained. When we last checked (September 2026) it held 7,219 technology definitions across 108 categories, with 6,541 icons for the UI.

With browser mode switched on for a scan, Playwright runs Chromium so technologies that only appear after render still show up. Gemini 2.5 Flash is optional on top of that: it can double-check borderline detections and write a short company summary from the page.

1. Submit URL

FastAPI /api/v1/analyze

2. Fetch + match

HTML, headers, 7,219 patterns

3. Render on request

Playwright / Chromium

4. Optional AI

Gemini validate + summary

The app runs on Google Cloud Run at techstack.pacing.agency, behind Cloudflare Zero Trust, so you sign in with a Pacing account to use it. The team opens it in the browser, and the same API is set up for n8n with a service token.

Mode	What it does	When we use it
Complete scan	Every one of the 7,219 definitions, no AI filter (about 40 seconds)	Audit, first look
Browser	Playwright renders JS-heavy sites	SPA / tag-heavy pages
Quick scan	Scripts, headers, cookies and network requests only: about 5 seconds, finds roughly 70 to 85% of technologies	When we need a fast first pass
AI validation	Gemini re-checks borderline detections (the slowest option)	When accuracy matters most
Company summary	Gemini pulls a logo, description and links from the page	Pitch prep
Export	JSON, CSV, or PDF	Handover and CRM

What changed

A pitch or audit starts with a stack list we can back up, not a guess.
The API is set up so n8n can scan a new client's site without anyone opening the UI.
Competitor sites get the same scan, so the comparison is like for like.

It won't write the plan for you. The list is the starting point, and the meeting still has to decide what to change.

Why it worked

We own the scan, the definitions are maintained, and the same API serves the browser and our automations.

Maintained definitions: 7,219+ technologies and 108 categories from a repo that's still being updated.
Render when the HTML isn't enough: Playwright covers sites that hide their stack until JavaScript runs.
API for ops: automations can run the same job we run by hand, so it doesn't depend on someone remembering to open it.

Screens