Free Online Developer tools
Every developer tool here runs entirely in your browser — instant results, no sign-up, and nothing you enter is ever uploaded. Pick a tool to get started.
- JSON Formatter & Validator
Format, beautify, validate and minify JSON online. Clear error messages with line and column — fast, free, and fully in your browser.
- JWT Decoder
Decode a JSON Web Token to read its header and payload. Runs entirely in your browser — your token is never uploaded or logged.
- CSV to JSON Converter
Convert CSV to JSON and JSON to CSV online. Handles quoted fields and headers correctly, entirely in your browser — no upload.
- Unix Timestamp Converter
Convert Unix timestamps to human dates and dates back to epoch seconds. Handles seconds and milliseconds, in UTC and your local time.
- HTML Entity Encoder & Decoder
Encode text to HTML entities or decode entities back to text. Escapes <, >, &, quotes and non-ASCII — runs entirely in your browser.
- Regex Tester
Test regular expressions against your text with live match highlighting, capture groups and flags. Free and fully in your browser.