I Built 10 Developer Tools in One Day - Here They Are (Free, Open Source)

Last week I had a single tool: a JSON-to-TypeScript converter. Today I have 10. I spent a day building a full suite of developer tools - all free, all client-side (nothing leaves your browser), and all open source on GitHub. The Suite DevForge is a collection of tools I built because I kept opening 15 different tabs every day: 1. JSON ? TypeScript Paste JSON, get TypeScript interfaces or types. Supports nested objects, arrays, custom root names. 2. CSV ? JSON Bidirectional conversion with header detection and delimiter support (comma, semicolon, tab). 3. Regex Tester Live regex testing with flags (g, i, m, s, u, y), match highlighting, and replace functionality. 4. Base64 Encoder/Decoder Encode text to Base64 and decode Base64 back to text. Unicode-safe. 5. JWT Decoder Decode JWT tokens into header, payload, and signature components. Read-only - no verification, no security risk. 6. SQL Formatter Uppercase keywords, indentation control. Handles SELECT, JOIN, INSERT, CREATE - the common stuff. 7. Diff Checker Side-by-side text comparison with LCS-based diff algorithm. Color-coded additions and removals. 8. UUID Generator Generate UUID v4 (or v1) in bulk. Copy individual or all at once. 9. Timestamp Converter Convert Unix timestamps to readable dates and back. Shows seconds, milliseconds, ISO 8601, UTC, and relative time. 10. Color Converter Convert between HEX, RGB, HSL, and CMYK. Color picker, presets, named color support. The Tech Stack Zero frameworks. Zero dependencies. Zero backend. Every tool is a single HTML file with embedded CSS and JavaScript. They all run entirely in the browser - no data is sent to any server. Hosted on GitHub Pages. Free forever. Why I Built This I'm a solo developer based in Nepal. Building things that help other developers is how I learn, grow, and (hopefully) earn. The suite is free, but there's a Pro tier ( one-time) that unlocks: File exports Batch operations Custom naming conventions Priority support I also do freelance development