Weblyzer - Web Analyzer

Weblyzer tells you exactly what a website is built with - and, unlike most detectors, how its back-end, hosting, security, email and performance hold up - entirely in your browser. No backend server, no account, no tracking.

Click the toolbar icon on any site and Weblyzer identifies its stack instantly, grouped into clear categories, with a vendor logo, detected version and confidence level for each result. A number badge on the icon shows the count before you even open the popup.

WHAT IT DETECTS 1,213 technology signatures across 27 categories:

front-end frameworks, web frameworks, UI and CSS libraries, JavaScript libraries, content management systems, e-commerce platforms, back-end frameworks, programming languages, databases, web servers, hosting and PaaS, CDNs, caching, backend-as-a-service, API layers, site search, media and video, AI and LLM services, Web3 and wallet infrastructure, payment providers, security and bot defence, monitoring and APM, analytics, marketing and CDP, reviews and user-generated content, shipping and fulfilment, and general widgets.

Each result shows its category, the detected version where available, how confident the detection is, and the evidence that produced the match - so you understand a site's architecture at a glance instead of guessing.

Coverage is deliberately deep where other detectors are thin, including payment gateways, hosting providers, e-commerce enablers and shipping services used in Indonesia and Southeast Asia.

WHAT'S NEW IN 0.21

• What changed since your last visit - Weblyzer remembers each site's stack and shows you exactly what was added, removed or upgraded, plus how the scores moved
• More accurate versions for the two most common front-end frameworks, including in production builds where the version is normally invisible
• 716 vulnerability advisories across 59 libraries, matched against the versions actually detected, all offline
• Exposure check - one click tests a short list of paths that are public by convention on the site you are viewing, and reports the ones that answer with something they should not
• Keys and source maps in the bundle - finds credentials left in front-end code and reachable source maps, separating keys that are public by design from the ones that should never ship. Values are always shown masked
• Email authentication grade - SPF, DKIM, DMARC, MTA-STS, BIMI and DNSSEC, with a plain answer to "can this domain be spoofed?"
• Page weight - what the browser actually downloaded, by resource type, first party vs third party, cache hits, compression, HTTP version and the heaviest files
• Compare two sites side by side from your history

SITE HEALTH, SCORED LOCALLY

• Security grade (A+ to F) - audits common response-security headers and flags version or information leaks
• Performance grade (A to F) - based on the page's real Core Web Vitals, alongside the full page-weight breakdown
• Known vulnerable versions - detected library versions matched against a bundled advisory database built from open-source security data, with CVE links and the version that fixes each finding

DIG INTO THE BACK-END

• API map - the real REST, GraphQL, WebSocket and SSE calls a page makes, with operation names, response status codes, copy-as-cURL, and optional schema introspection
• Hosting & network - server IP, ASN, ISP, location and reverse DNS, plus the TLS version and server certificate (Firefox)
• DNS & email - reads public DNS records to identify the mail host, DNS host and certificate authority, and grades the domain's email authentication
• Well-known recon - reads public files such as robots.txt and security.txt to reveal how the site handles identity and disclosure
• JWT inspector - decodes auth tokens from the page's own storage locally (header and claims only; never verified or sent anywhere)
• SEO & meta inspector - title, description, canonical, social card tags, hreflang and structured data
• Cookie inspector - every cookie with its Secure / HttpOnly / SameSite flags
• Third-party map - every external domain the page talks to, grouped by category

WORK THE WAY YOU WANT

• Compact popup for a fast glance; a six-tab full report for the detail
• Export any report as an image, text, Markdown or JSON
• History of the sites you have analyzed, with side-by-side comparison
• Available for Chrome, Firefox, and Firefox for Android

PRIVACY FIRST 100% local by default. Weblyzer has no backend and sends nothing to the developer. Every network request is opt-in and reaches only the site you are on, the scripts that site already loaded, or a clearly labelled public IP/DNS service. See the privacy policy for full details.

Weblyzer is an independent tool. It is not affiliated with, endorsed by, or sponsored by any of the vendors whose products it may identify. Vendor logos shown in the interface are used solely to identify a detected technology.