ToolsPlanet

Developer Tools

Handy utilities for developers, open-source contributors, and GitHub users.

When you're debugging a JWT at 2am, prototyping a JavaScript snippet, or polishing a GitHub README before a release, you don't need another login screen — you need the answer. The tools below run entirely client-side: tokens you decode never leave the tab, code you paste isn't logged, and there's no quota to hit.

Use the JWT Decoder to inspect headers and payloads, the JavaScript Tester to run snippets in a sandboxed playground, and the README Generator to scaffold a polished profile or project page with live preview. Working with JSON specifically? Head to our dedicated JSON Tools hub for the formatter, diff viewer, and JSON-to-CSV / YAML / TypeScript converters.

README Generator

Create professional README.md files for your GitHub profile or project repos with a live preview.

JWT Decoder

Instantly decode JSON Web Tokens (JWT) to view their header and payload claims securely.

JavaScript Tester

HTML, CSS & JS playground with live preview and captured console — like CodePen, fully client-side.

JSON Tools →

Formatter, diff, and JSON-to-CSV / YAML / TypeScript converters — now in their own category.

GitHub README Generator

Create a professional README.md for your GitHub project or GitHub profile in minutes. Our generator provides structured templates with live Markdown preview — just fill in your project name, description, features, and installation steps to get a polished, ready-to-commit README file.

JWT Decoder for OAuth Debugging

Paste any JSON Web Token to inspect its header, payload, and expiry client-side. Our JWT decoder never sends the token to a server — critical when debugging production auth flows or troubleshooting iss/aud claim mismatches.

Why Developers Choose Our Tools

JWT Decoder for Debugging Decode JSON Web Tokens to inspect header claims, payload data, expiration times, and roles — without installing any library.
No Installation Required All tools run entirely in the browser. No npm packages, no CLI tools, no extensions — just open and use.
Privacy & Security JWT tokens and any sensitive payloads are processed locally. Nothing is sent to a server — critical when working with production secrets.
Copy & Download One-click copy to clipboard or download formatted output as a file — ready for your project or documentation.

Tip: Open Source Contributors

A well-structured README is the first thing users see on your GitHub repo. Use our README generator to include installation steps, usage examples, and contribution guidelines — it significantly increases project engagement and stars.