All-in-one developer toolbox
The all-in-one debugging toolbox for front-end developers
Color picker, UA switcher, device preview, API debugging, CORS and header checks, page analysis and more — one extension, every browser.
ChromeEdgeFirefoxSafari
ZyDevKit
All-in-one developer toolbox
Developer utilities
User-Agent Switcher
API Debugger
CORS Checker
✓ Inspect, transform, validate and export without moving work between unrelated sites.
Features
Powerful features for efficient development
Everything you need to debug, design and test the current page — without leaving it.
Advanced Color Picker
Eyedropper, magnifier, HEX/RGB/HSL/OKLCH formats and code exports.
User-Agent Switcher
Simulate mobile, WebView and desktop browsers with one click.
Device Preview
Preview responsive layouts across target device sizes.
API Debugger
Environments, variable checks, response assertions, summaries, cURL import and code export.
CORS Checker
Preflight analysis with clear server-side fix suggestions.
Page Analysis
Performance, SEO checklist and page color extraction.
Browser Data Workbench
Manage current-site browser data and create password-encrypted, origin-bound snapshots with conflict preview and confirmed restore.
Local-first
Local tools, close to the work
ZyDevKit keeps everyday debugging fast and contained inside the browser.
Your data stays local
Tool input, request collections and settings remain on your device unless you choose to send a request.
Four browser targets
Use the same workflow across Chrome, Edge, Firefox and Safari builds.
Built for active debugging
Inspect, transform, validate and export without moving work between unrelated sites.
Works on every major browser
Install ZyDevKit
Pick your browser and get started in seconds.