StackPeek · Free Chrome extension
See What Any Website Is Built With
StackPeek is a free website technology checker for Chrome: click the icon on any page to see what the website is built with, from its CMS and front-end framework to analytics, ad tech and hosting, with no account and no lookup limits.
- Version 1.1.0
- Updated 14 Aug 2026
- Free · 100% local
A free website technology checker in your side panel
StackPeek reveals a website's technology stack in a clean side panel. One click shows its content management system, front-end framework, e-commerce platform, analytics, advertising tools, hosting and more. Each detection shows the technology's logo, its version where available, and the exact evidence behind it, so you are not left guessing why a result appeared.
What StackPeek detects on a website
Results are grouped by category so you can read a site's stack at a glance.
- Content management system
- Front-end framework
- E-commerce platform
- Analytics tools
- Advertising and ad tech
- Hosting
- Version numbers where available, with the matching evidence for every detection
How to check what a website is built with
Detection runs only when you ask for it, never automatically.
- Open the site you want to check and click the StackPeek icon.
- StackPeek reads the current page's markup, scripts and response headers.
- It matches them against its built-in database of technology signatures.
- Results appear in the side panel, grouped by category.
- Click any result to see which signals matched, copy a clean summary of the stack, or revisit sites in your local history.
Who uses a tech stack detector
StackPeek is built for SEO and marketing professionals researching prospects and competitors, developers curious about how a site is built, and agencies qualifying leads. Because there are no lookup limits, you can check as many sites as you like, and the copyable summary drops straight into notes or a lead sheet.
100% local, transparent and unlimited
Detection runs against the page you are already viewing, inside your browser. The only network request it makes is reading the current page's own response headers. There is no server, no account and no telemetry. StackPeek requests only the minimal permissions needed to inspect the tab you choose to scan, has no access to other sites, collects no personal data and sends nothing anywhere. Your history of checked sites is stored only on your device.
What StackPeek does not do
StackPeek does not scan sites in the background or crawl a whole domain. It inspects the tab you choose, when you click the icon, using that page's markup, scripts and response headers. Its results come from its built-in signature database, so it reports what those signals reveal on the page you are viewing.
About StackPeek
Frequently asked questions
How can I tell what a website is built with?
Install StackPeek, open the site and click the StackPeek icon. It reads the page's markup, scripts and response headers, matches them against its built-in signature database, and lists the CMS, framework, e-commerce platform, analytics, ad tech and hosting it finds in a side panel, grouped by category.
Is StackPeek free, and is there a limit on lookups?
StackPeek is free and has no lookup limits. Because detection runs locally in your browser and there is no server to meter, you can check as many sites as you like. You do not need an account to use it.
How accurate are StackPeek's detections?
Every detection is transparent. Click any result to see which signals matched, so you can judge each one yourself rather than trusting a black box. Where available, StackPeek also shows the technology's version alongside its logo and the evidence behind the match.
Does StackPeek send the sites I check to a server?
No. Detection runs inside your browser against the page you are viewing. The only network request it makes is reading the current page's own response headers. There is no server, no account and no telemetry, it collects no personal data, and your history is stored only on your device.
Does StackPeek run on every page I visit?
No. Detection runs only when you click the StackPeek icon, never automatically. It requests only the minimal permissions needed to inspect the tab you choose to scan and has no access to other sites.
Can I copy or save a site's tech stack?
Yes. StackPeek lets you copy a clean summary of a site's stack for your notes, and it keeps a local history of the sites you have checked. That history is stored only on your device, so you can revisit past lookups without sending anything anywhere.