About K-Lab

K-Lab is a collection of free, privacy-focused developer tools. All tools run entirely in the browser — no data is sent to any server (except CORS Tester, which needs server-side requests by nature).

Why K-Lab?

Built by a developer, for developers. Every tool is designed to be fast, distraction-free, and privacy-respecting. No sign-ups, no tracking beyond basic analytics, no ads interrupting your workflow.

The Tools

• JSON Formatter — format, validate, and explore JSON
• JSON to Lua Converter — convert JSON structures to Lua tables
• JSON to TypeScript Converter — generate TypeScript interfaces from JSON
• Code Diff — side-by-side code comparison
• JWT Debugger — decode and inspect JSON Web Tokens
• Cron Parser — parse and explain cron expressions
• Retry Backoff Calculator — visualize retry and backoff strategies
• Unicode Text Inspector — inspect Unicode characters and codepoints
• ID Toolkit — decode and analyze various ID formats
• CORS Tester — test CORS headers on any URL

Privacy

Your data stays in your browser. All processing happens client-side — nothing is uploaded or stored on our servers. For full details, see our Privacy Policy.