Your standard output for dev tools.
Format, convert, encode, generate — all in one place.
Stdout is a lightweight, in-browser developer tools platform.
No backend. Everything runs locally in your browser.
Built for trust, performance, and extensibility.
| Tool | Description |
|---|---|
| JSON Format/Validate | Format, validate & beautify JSON with strict RFC compliance |
| XML Format/Validate | Beautify, minify & validate XML |
| HTML Beautify/Minify/Validate | Beautify, minify & validate HTML |
| SQL Formatter | Format and beautify SQL queries |
| CSS Beautifier/Minifier | Beautify or minify CSS (format/minify) |
| JS Beautifier/Minifier | Beautify or minify JavaScript (format/minify) |
| CSS Inliner (Email) | Inline CSS styles into HTML for email templates |
| JSONPath Tester | Test JSONPath expressions against JSON data |
| Schema Diff | Compare two JSON schemas side by side |
| Payload Comparator | Compare two JSON payloads and highlight differences |
| Regex Tester | Test regular expressions with live matching |
| Java Regex Tester | Test Java-style regular expressions |
| XPath Tester | Run XPath expressions against XML |
| Credit Card Generator & Validator | Luhn check and generate test card numbers |
| Cron Parser | Build and parse cron expressions (Quartz-style) |
| JSON ↔ YAML | Convert between JSON and YAML formats |
| CSV ↔ JSON | Convert between CSV and JSON formats |
| JSON → Table | Visualize JSON data as a table |
| JSON → Types | Generate TypeScript types from JSON |
| JSON ↔ Query String | Convert between JSON and URL query strings |
| Epoch Timestamp | Convert between Unix timestamps and dates |
| Number Base | Convert numbers between bases (bin, oct, dec, hex) |
| Color Converter | Convert colors between HEX, RGB, HSL formats |
| Image ↔ Base64 | Convert images to/from Base64 strings |
| .env Converter | Convert .env files to Netlify, Docker, YAML formats |
| CSS Units | Convert between CSS units (px, rem, em, vw) |
| XSD Generator | Generate minimal XSD schema from XML |
| XSLT Transformer | Transform XML using XSLT stylesheet |
| XML ↔ JSON | Convert between XML and JSON |
| CSV → XML | Convert CSV to XML (first row as element names) |
| URL Encode/Decode | Encode and decode URL components |
| Base64 String Encode/Decode | Encode and decode Base64 strings |
| HTML Entity Encode/Decode | Encode and decode HTML entities |
| JWT Debugger | Decode and inspect JWT tokens |
| QR Code | Generate QR codes from text or URLs |
| Gzip | Compress and decompress with Gzip |
| Certificate Inspector | Inspect and decode X.509 certificates |
| Convert File Encoding | Decode bytes from charset or encode text to UTF-8 |
| Message Digester | MD5, SHA-1, SHA-256 hashes |
| HMAC Generator | Generate HMAC signatures |
| String Utilities | Convert between camelCase, snake_case, and more |
| String Escaper (JSON, XML, CSV, SQL, Java, JS) | Escape or unescape text for JSON, XML, CSV, SQL, Java/.NET, JavaScript string literals |
| List Collator | Merge, sort, and deduplicate lists |
| Text Analyzer | Count words, characters, sentences in text |
| Text Diff | Compare two texts and highlight differences |
| Lorem Ipsum | Generate placeholder text |
| URL Parser | Parse and inspect URL / query string |
| List of MIME Types | Reference table of common MIME types |
| Markdown Preview | Live preview of Markdown with GFM support |
| UUID Generator | Generate UUIDs (v1, v4, v7) |
| Password Generator | Generate secure passwords with custom rules |
| Random String | Generate cryptographically secure random strings |
| Mock Payload | Generate mock JSON data from a schema |
| ASCII Art | Turn text into ASCII art |
| Log Generator | Generate synthetic log data for testing |
| SVG Viewer | View, edit, and export SVG graphics |
| Image Resizer | Resize images with format conversion |
| cURL Builder | Build cURL commands visually |
| HAR Viewer | Inspect HAR (HTTP Archive) files |
| CSV Viewer | View and search CSV files in a table |
| Math Calculator | Evaluate math expressions |
- 100% client-side processing
- No data collection
- Works offline — No remote APIs or CDN fonts; web build uses PWA cache after first load; desktop app runs fully offline
- Modular architecture
- Easy to extend with new tools
- Privacy First — No server, no tracking, no data leaves your browser.
- Lightweight — Minimal dependencies.
- Modular — Each tool is isolated and independently extendable.
- Open Source (MIT) — Free to use, modify, and distribute.
macOS (desktop app)
brew tap cminhho/tap
brew install --cask cminhho/tap/stdoutThen open stdout from Applications or Spotlight. If macOS blocks the first open (“developer cannot be verified”), run once: xattr -cr /Applications/stdout.app
Web — Run locally (see below) or deploy the built dist/ to any static host.
Clone and install:
git clone https://github.com/cminhho/stdout.git
cd stdout
npm installWeb (Vite)
npm run dev # Dev server
npm run build # Production build → dist/Desktop (Electron)
npm run electron:dev # Dev with hot reload
npm run electron:build:mac # Build macOS app (arm64 + x64) → release/
npm run electron:build:win # Build Windows
npm run electron:build:linux # Build Linuxsrc/
components/ # App + UI primitives (ToolLayout, CodeEditor, ui/)
contexts/ # React context (Settings)
hooks/ # useToolEngine, useCurrentTool, useToolTracking
pages/ # Tool pages by domain (converters, encode, formatters, …)
tools/ # Tool registry (registry.ts), routing, types, tracking
utils/ # Domain logic + UI helper (encode, validators, cn, …)
Tools are registered in tools/registry.ts; each page is self-contained and lazy-loaded.
Contributions are welcome.
- Fork the repository
- Create a feature branch
- Commit your changes
- Submit a pull request
Please keep tools modular and avoid unnecessary dependencies.
MIT License
Copyright (c) 2026 Stdout
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction...
(Include full MIT license text here or create a separate LICENSE file.)
