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A free online collection of Developer Tools tools. All processing runs in your browser, no upload, no registration.

/ /Regex Tester 📋Regex Templates 🎨RGB ↔ HEX Converter 🗄️SQL Formatter 🌐Extract HTML Meta 📊CSV to Markdown Table 🔄Transpose Table 🔌Random Port 📋Random Test Data ⏰Timestamp Converter 🌍Time Zone Converter 🔑Random Password 🛡️Password Strength 👤Random Name & Address 📱Test Phone Number 🏷️SKU Generator 📐Square & Cube Calculator 📏Proportion Converter 🔐Hash Generator 🔢Base Converter ⏰Cron Expression Generator 🔒Base64 Encode / Decode 🔤Character Encoding Converter 💳Test Bank Card Number ⚖️BMI Calculator 🎂Age Calculator 📊Code128 Barcode 🔒Base32 Encode / Decode 🎨Color HSL Converter 🎨CSS Beautify & Minify 📈Function Graph Plotter 📐Geometry Area Calculator 🔐HMAC-SHA Crypto 🌐HTML Beautify & Minify 🔐JWT Parser & Validator 🌐Random MAC Generator 🧩SVG Preview & Format 🔤Unicode ↔ Chinese Converter 🔤Variable Name Converter 📅Workday Calculator 🗜️ZIP Preview & Extract 📊Variance & Std Dev Calculator 📱Batch QR Code Generator 📅Batch Random Date 🏷️Batch SKU Generator 📦Tracking Number Validator 📧Random Email & URL 🎲Weighted Random Draw 🔣HTML Entity Encode / Decode 📱QR Code Generator 📶WiFi QR Code Generator 🈶TXT Encoding Converter ↵Newline Converter

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Unit Converters URL & Encoding Video Tools Audio Tools GIF Tools CSV & Data Text Tools JSON/XML工具 SEO Tools Business & Finance PDF Tools Image Tools

About this category

Development throws up a steady stream of small tasks: decode a Base64 blob, compute an MD5, turn a Unix timestamp back into a readable date, check whether a regex actually matches. Installing a desktop app for that is overkill, but pasting keys and tokens into an unknown server is a real risk. Every tool here executes locally with plain JavaScript and the Web Crypto API, so sensitive data never leaves the browser and you can safely work with internal configs and credentials.

Frequently asked questions

Is it safe to paste API keys and tokens?

Yes. Hashing, encryption and encoding all run locally through browser JavaScript and the Web Crypto API. Nothing is transmitted.

Which regex flags does the tester support?

All JavaScript flags — g, i, m, s, u and y — with live highlighting of matches and capture groups.

Does the timestamp converter handle milliseconds?

Yes. It auto-detects 10-digit second and 13-digit millisecond timestamps and shows both local time and UTC.