I Built 47 Free Dev Tools That Run Entirely in Your Browser

Every developer has done it — copy-pasted a JWT, a private key, or a JSON blob with sensitive data into some random website and held their breath. Wondering if it was being logged, tracked, or worse. Every developer has done it — copy-pasted a JWT, a private key, or a JSON blob with sensitive data into some random website and held their breath. Wondering if it was being logged, tracked, or worse. I built KRUMB.DEV because I wanted tools that didn't make me feel dirty after using them. What Is It? 46 developer tools, all in one place. No signup. No uploads. No tracking. Open source. The terminal-inspired interface isn't just aesthetic — it's a constraint. Every tool fits in a single column, zero sidebar, zero popups. Just you and the tool. What's Inside Formatters — JSON, SQL (17 dialects), HTML, JavaScript, CSS Encoders — Base64, URL, JWT decoder, YAML↔JSON, JSON↔CSV Generators — Passwords, UUIDs (v1/v3/v4/v5), hashes (MD5/SHA/HMAC), QR codes, Lorem Ipsum, color palettes, CSS gradients/shadows/grids, meta tags, robots.txt, .gitignore Testing & Debugging — Regex tester, diff checker, webhook tester, cURL→code, HTTP status reference, cron expression builder Converters — Unix timestamps, hex↔RGB, binary, SVG→JSX, JSON→TypeScript, HTML playground, markdown editor Network — DNS lookup, SSL checker, IP lookup, QR code decoder, IBAN validator Why I Built It This Way Most "free" dev tools follow the same pattern: create an account, hit a rate limit, and wonder if your data is being stored somewhere. KRUMB.DEV flips that: Everything runs in your browser — JSON, JWT, source code, passwords never touch a network request Zero accounts — open the page, use the tool, leave. No signup wall between you and the output Clean interface — ⌘K opens a command palette to jump to any tool in seconds Open source — MIT license, deploy your own if you want The Tech Next.js, TypeScript, and Tailwind. Static-first, client-side execution for all core tools. Server routes exist only for DNS/SSL l