Developer Utilities,
Without the Context Switch
Decode JWTs, encode Base64, convert CSV, test regex, generate UUIDs — all in your browser, all free, all instant. No Postman, no terminal, no sign-up.
5 Tools for Everyday Dev Work
Each tool covers a specific, recurring developer task. No tab-switching, no installs, no rate limits.
JWT Decoder
Decode and inspect JSON Web Tokens instantly. View the header, payload, and signature in a readable format. Verify token structure without leaving your browser.
Base64 Encode/Decode
Encode any text or data to Base64 format, or decode Base64 strings back to readable text — essential for HTTP headers, API authentication, and binary data handling.
CSV to JSON
Convert CSV files or pasted CSV data to clean, properly structured JSON. Auto-detects column headers and maps rows to JSON objects. Great for data migration and API prep work.
Regex Tester
Test and debug regular expressions in real time. See all matches highlighted in your test string, inspect capture groups, and toggle flags (i, g, m) instantly.
UUID Generator
Generate cryptographically random UUID v4 strings — one at a time or in bulk. Essential for database primary keys, session tokens, and unique identifiers in any application.
Zero Setup
No npm install, no Docker, no config files. Open the URL, start working. All tools run instantly without any environment setup.
About This Utility
This tool is provided completely free of charge by Mavertex. Built by Kumar (an independent UI developer), our platform ensures your privacy by executing all operations strictly within your local browser DOM.
We prioritize zero-trust architecture. No files or inputs are ever uploaded to remote servers. This page serves as both an interactive web application and an educational resource explaining the mechanics of client-side operations. For further details on transparency and third-party network usage (including AdSense), please review our Privacy Policy.
Privacy-First
Your JWTs, CSV data, and regex patterns never leave your browser. Everything processes locally — no server, no logs, no exposure.
About This Utility
This tool is provided completely free of charge by Mavertex. Built by Kumar (an independent UI developer), our platform ensures your privacy by executing all operations strictly within your local browser DOM.
We prioritize zero-trust architecture. No files or inputs are ever uploaded to remote servers. This page serves as both an interactive web application and an educational resource explaining the mechanics of client-side operations. For further details on transparency and third-party network usage (including AdSense), please review our Privacy Policy.
Offline Capable
Once loaded, most tools work even when you're offline or on a restricted corporate network. Great for working on trains or in secure environments.
About This Utility
This tool is provided completely free of charge by Mavertex. Built by Kumar (an independent UI developer), our platform ensures your privacy by executing all operations strictly within your local browser DOM.
We prioritize zero-trust architecture. No files or inputs are ever uploaded to remote servers. This page serves as both an interactive web application and an educational resource explaining the mechanics of client-side operations. For further details on transparency and third-party network usage (including AdSense), please review our Privacy Policy.
More Tools You Might Need
These tools are in other categories but are frequently used alongside developer work.
Frequently Asked Questions
Is it safe to paste JWTs into the decoder? ↓
Yes. JWT decoding happens entirely in your browser using JavaScript. The token is never sent to our servers. That said, avoid pasting production tokens containing sensitive user data in any public environment — use these tools on your local machine for sensitive tokens.
What's the difference between encoding and encrypting Base64? ↓
Base64 is encoding, not encryption. It converts binary data to a safe ASCII string format for transport (e.g., in HTTP headers or data URIs). It provides no security — anyone can decode it. Never use Base64 to "hide" sensitive data.
Why does my regex work in JavaScript but fail in Python? ↓
Different programming languages implement slightly different regex flavors. JavaScript uses the ECMAScript regex engine. Our Regex Tester uses JavaScript's engine. Python, PCRE, and .NET may differ in lookaheads, named groups syntax, and flag behavior.
Are UUID v4 values truly unique? ↓
UUID v4 generates from 122 bits of randomness. The probability of collision is astronomically low (1 in 5.3×10³⁶). For all practical purposes, generated UUIDs are unique. Our tool uses the browser's Web Crypto API (crypto.randomUUID()) for true randomness.