The everyday tools developers need, all in one place.
Format data, compare text, and convert common developer formats with quick, focused utilities. Your input stays in your browser.
No account. No installation. No upload of your tool input.
All Tools
View allJSON Formatter
Format, validate, and minify JSON data with syntax highlighting and error detection.
JWT Decoder
Decode and inspect JSON Web Tokens. View header, payload, and expiration info.
UUID Generator
Generate cryptographically secure UUID v4 values. Single or bulk generation.
Base64 Encoder / Decoder
Encode text to Base64 or decode Base64 back to plain text. Supports UTF-8.
SQL Formatter
Format and beautify SQL queries with configurable indentation and keyword casing.
URL Encoder / Decoder
Encode URL components safely or decode percent-encoded text in your browser.
XML Formatter
Validate and indent XML documents locally, with helpful errors for malformed markup.
HTML Formatter
Make compact HTML easier to read with consistent indentation.
CSS Minifier
Remove unnecessary CSS whitespace and comments while checking basic syntax.
Regex Tester
Test JavaScript regular expressions against sample text and inspect matches.
Markdown Previewer
Preview common Markdown headings, lists, emphasis, and code without sending text anywhere.
JSON to CSV Converter
Convert an array of JSON objects into properly escaped CSV data.
Timestamp Converter
Convert Unix seconds, milliseconds, or date strings into readable UTC and local dates.
Hash Generator
Generate SHA-1, SHA-256, SHA-384, or SHA-512 digests locally with Web Crypto.
Diff Checker
Compare two text blocks and review added, removed, and unchanged lines.
Why DevToolBox?
Instant Results
All tools run entirely in your browser. No server round-trips, no waiting.
Private & Secure
Your data never leaves your device. We never log, store, or transmit your input.
Always Free
Core tools are free forever. No account required to get started.