Free Developer ToolsThat Just Work
Fast, free, and privacy-first. All tools run entirely in your browser — no data is ever sent to a server. No signup required.
JSON Formatter & Validator
Beautify, minify, and validate JSON data instantly. Detect syntax errors with clear messages.
Regex Tester
Test regular expressions against sample text with real-time match highlighting and common patterns.
Base64 Encoder/Decoder
Encode text to Base64 or decode Base64 strings back to text. Supports UTF-8 characters.
JWT Decoder
Decode and inspect JSON Web Tokens. View header, payload, claims, and expiration status.
Hash Generator
Generate MD5, SHA-1, SHA-256, and SHA-512 hashes from any text using the Web Crypto API.
URL Encoder/Decoder
Encode special characters for URLs or decode percent-encoded strings. Supports encodeURI and encodeURIComponent.
Color Converter
Convert colors between HEX, RGB, and HSL formats with a live color preview.
Cron Expression Builder
Build cron schedules visually. See human-readable explanations and next run times.
Unix Timestamp Converter
Convert epoch timestamps to dates and back. Live current timestamp display.
JSON Diff Viewer
Compare two JSON objects and see added, removed, and changed values highlighted.
Markdown Preview
Write Markdown and see it rendered in real-time. Supports full GFM syntax.
100% Client-Side
Your data never leaves your browser. No server processing, no logging.
Instant Results
No loading spinners. Tools respond in real-time as you type.
Free Forever
No signup, no paywall. All tools are free to use without limits.
Why DevToolBox?
DevToolBox provides the essential developer utilities you need every day, without the bloat. Whether you're debugging a JSON API response, testing a regex pattern, encoding data for an API call, or inspecting a JWT token, we've got you covered.
Unlike other tools, DevToolBox is built with privacy first. Every tool runs entirely in your browser using JavaScript — your data is never transmitted to any server. This makes it safe to use with sensitive data like API keys, tokens, and internal configurations.
Built by developers, for developers. New tools are added regularly.