DevTools Pro - Developer Toolbox

DevTools Pro: JSON formatter, API client, JWT, Base64/URL, timestamp, regex. Free, zero permissions, local-first.

DevTools Pro is a free developer toolbox that puts 7 essential tools at your fingertips — a modern UI, zero permissions, and no data collection. Every tool works right in the toolbar popup, and one click (⤢) expands it into its own floating window — no extra browser tab needed. ━━━━━━━━━━━━━━━━━━━━ 🧰 TOOLS INCLUDED 1. JSON Formatter • Parse & format with tree view (collapsible nodes) • Deep search — find any key or value instantly • Copy entire subtrees as JSON with one click • Minify to single-line output • Handles large files gracefully (progressive rendering) 2. API Client • Send HTTP/HTTPS requests: method, URL, query params, headers, body • Body types: JSON, text, x-www-form-urlencoded, form-data • Response as Pretty / Raw / collapsible tree / headers, with status code, timing and size • JSON editor with auto-closing brackets & quotes, and a tolerant repair pass that fixes unquoted values, missing commas and unclosed brackets • Errors are underlined right in the text, plus a plain-language reason • Pre-send checks flag anything the browser will silently change (forbidden headers, duplicate header keys, GET with a body) • Requests go straight from your browser to the URL you enter — we have no server and never see them 3. JWT Encode / Decode • Decode: Split header/payload/signature with expiry check • Encode: HS256/384/512 signing via Web Crypto API • 4 payload templates (Basic, Auth, Admin, API) • Custom expiration: minutes, hours, days, or specific date 4. Timestamp Converter • Unix seconds ↔ milliseconds auto-detection • UTC + local time dual display with timezone info • Real-time UTC + local clock • One-click "Now" button 5. Regex Tester • 7 built-in presets (email, URL, phone, IP, Chinese, etc.) • 12 regex snippet buttons for quick insertion • Real-time match highlighting with count • Flag selector (g, i, m combinations) 6. Base64 Encode / Decode • UTF-8 safe — handles Chinese and emoji • Bidirectional encode ↔ decode 7. URL Encode / Decode • Standard encodeURIComponent / decodeURIComponent • One-click copy ━━━━━━━━━━━━━━━━━━━━ 🔒 PRIVACY FIRST • Zero permissions — the extension requests nothing • No analytics, no tracking, no ads, no accounts • Your data is never collected or stored: nothing is written to disk, and closing the page clears it • The 6 converter tools run entirely on your device and make no network requests at all • The API Client sends a request only when you click Send, directly from your browser to the address you typed. There is no server of ours in between — we cannot see, store or relay your requests • Because no host permissions are requested, cross-origin API responses follow the browser's normal CORS rules: a response can be read only if the target server allows it • Open privacy policy linked below 🌐 INTERNATIONAL • Full English & Simplified Chinese support • Auto-detects browser language 💡 PERFECT FOR • Frontend/backend developers debugging APIs • QA engineers inspecting JWT tokens • DevOps engineers converting timestamps • Anyone working with encoded data ──────────────────────────── 📬 Support: 13531021638@163.com