v1.95.0 · Free browser extension

30+ DevTools.
One extension.

Console, Network, DOM, Storage, Mock API, Certificate Inspector, WebSocket monitor, DNS Leak Checker and 22 more tools — all inside your existing DevTools panel. Press F12 to start.

Chrome 88+ · Manifest V3 · Free · No account required

</> Kernel Extension — Console
❯ network inspect github.com
✓ POST /api/user 200 42ms
✓ GET /cdn/app.js 304 12ms
0 trackers detected
 
❯ cert inspect github.com
✓ TLS 1.3 · Grade A · 180 days remaining
✓ HSTS enforced · CSP present
 
❯ mock add /api/user
✓ Rule active · contains /api/user → 200
# 30+ tools. One extension.
Kernel Extension — attached0.0 KB transmitted
tools30+
trackers0
manifestMV3
accountnone
Features
Every tool you need.
Nothing you don't.

All tools live inside your existing DevTools panel — no new windows, no context switching. Grouped the way you'd already read a box model: the thing itself, out to your own workspace.

Content — what you’re looking at
Padding — headroom around it
Border — its security boundary
Margin — your own workspace
Console · Live
Console
Capture every log, warning and error with timestamps. Evaluate JavaScript against the live page.
Live
Network Inspector · Live
Network Inspector
Every fetch, XHR and resource load — method, status, headers, request body and response body.
Live
DOM Tree · Live
DOM Tree
Browse the live document tree with collapsible nodes. Inspect any element by CSS selector.
Live
Storage Editor · Read/Write
Storage Editor
Read, write and delete localStorage, sessionStorage and cookies with live page sync.
Read/Write
Mock API Interceptor · No server needed
Mock API Interceptor
Intercept fetch/XHR and return custom responses. Rules persist across page loads.
No server needed
WebSocket Inspector · Live
WebSocket Inspector
Live frame monitor for every WebSocket connection — search, direction filter, connection timeline.
Live
API Tester · Collections
API Tester
Built-in HTTP client with request collections, environment variables and response viewer.
Collections
Certificate Inspector · crt.sh
Certificate Inspector
TLS grade A–F, validity, SANs, HSTS preload status and Certificate Transparency log.
crt.sh
DNS Leak Checker · WebRTC
DNS Leak Checker
WebRTC ICE candidate harvesting detects IP leaks that VPNs miss. Risk-scored.
WebRTC
Tracker Map · Auto
Tracker Map
Visual map of every third-party tracker on the page — domain, category and request count.
Auto
Security Headers · A–F grade
Security Headers
Grade CSP, HSTS, X-Frame-Options, X-Content-Type-Options, Referrer-Policy and more.
A–F grade
Performance Timeline · Web Vitals
Performance Timeline
FCP, LCP, TTFB and full resource waterfall. Spot bottlenecks without leaving the tab.
Web Vitals
Accessibility Auditor · WCAG 2.1
Accessibility Auditor
WCAG 2.1 checks: alt text, form labels, heading order, ARIA roles — with fix guides.
WCAG 2.1
Color Palette · Extract
Color Palette
Extract every colour used on the page with hex, RGB and HSL. Copy any swatch instantly.
Extract
Fonts Inspector · Inspect
Fonts Inspector
Lists every typeface loaded on the page with family, weight, style and source URL.
Inspect
IndexedDB Inspector · Browse
IndexedDB Inspector
Browse every IndexedDB database — list stores, read entries and view key/value pairs.
Browse
PWA Inspector · PWA
PWA Inspector
Check manifest validity, service worker status, offline capability and installability.
PWA
Network Diff · Diff
Network Diff
Snapshot before/after a page action — diff shows added, removed and changed requests.
Diff
Privacy
Zero tracking.
Zero compromise.

Kernel Extension collects no telemetry, sends no analytics, and stores mock rules locally in chrome.storage.local. Everything else is read-only from the inspected tab.

No telemetry
No analytics
No cloud sync
Local-only storage
Read-only page access
Install
One click.
Any browser.

Live on Chrome, Edge, and Firefox — install directly from the official store, no developer mode required.

Available
🌐
Chrome
Chrome 88+ · Manifest V3
Available
🔷
Edge
Edge 88+ · Manifest V3
Available
🦊
Firefox
Firefox 128+ · Manifest V3
Coming soon
🧭
Safari
Safari 17+ · macOS
🌐Chrome InstallationChrome 88+ · Manifest V3
Step 01
Download

Click "Install Extension" above to download the package.

Step 02
Extract & load

Extract the ZIP to any folder on your computer.

Step 03
Open DevTools

Open Chrome and navigate to chrome://extensions

Free · No account · Chrome 88+ · Manifest V3

Prefer working in your editor? The API Tester is also available as a standalone VS Code extension.