Developer Tools
Free online tools for developers. All processing happens in your browser. Nothing is sent to any server.
Base64 Encode / Decode
Encode text to Base64, decode Base64 back to text, or convert files to Base64 data URIs. All processing happens in your browser.
Hash Generator
Generate MD5, SHA1, SHA256, SHA384, and SHA512 hashes for any text. All processing happens in your browser using the Web Crypto API.
Timestamp Converter
Convert between Unix timestamps and human-readable dates. Supports seconds, milliseconds, and timezone offset.
URL Encode / Decode
Encode strings for safe URL usage or decode percent-encoded URLs. Choose between encodeURIComponent and encodeURI modes.
UUID Generator
Generate UUID v4 (random) and v7 (time-ordered) UUIDs. Supports batch generation up to 100 UUIDs at once.
Password Generator
Create strong, random passwords with full control over length and character types. Includes a visual strength meter.
QR Code Generator
Generate QR codes from any text, URL, or data. Download as PNG. All processing happens in your browser. Nothing is sent to any server.
Currency Converter
Convert between 50+ currencies with real-time exchange rates. Useful for cross-border payments, international transactions, and multi-currency financial calculations.
Acquiring Margin Calculator
Calculate processing fee revenue, channel cost, FX margin, total gross margin, and export merchant quote assumptions.
HMAC Signature Generator
Generate HMAC (Hash-based Message Authentication Code) signatures. Essential for payment gateway integration, API authentication, and webhook signature verification.
Word Counter
Count characters (with and without spaces), words, lines, sentences, and paragraphs in real-time. All processing happens in your browser.
Color Converter
Convert between HEX, RGB, HSL, HSV, and CMYK color formats. Real-time preview swatch. All processing happens client-side.
Regex Tester
Test regular expressions in real-time. Enter a regex pattern and test text to see matches highlighted with detailed match information.
Payment Webhook Simulator
Simulate payment callbacks from Alipay, WeChat Pay, and Stripe. Fill in parameters, generate a signed POST request, and send it to your webhook URL for testing.
RSA Key Pair Generator
Generate RSA public/private key pairs (2048 or 4096 bits) directly in your browser. Export keys in PEM format.
Cron Expression Generator
Build cron expressions visually using dropdown selectors. See the next 10 scheduled execution times in real-time. Includes common presets.
frp Tunnel Config Generator
Generate frpc.ini files for HTTP and TCP tunnels. Copy the config or download it as a file.
Markdown Preview
Write Markdown with real-time HTML preview. Supports GitHub Flavored Markdown (GFM) including tables, code blocks, task lists, and more.
JSON Formatter
Format, validate, and compress JSON. Tree view, error detection with line/column numbers, copy formatted or minified output. All client-side.
CodeTools Toolbox - Free online developer tools.