Developer Tools
Encode, decode, convert and debug — fast dev utilities.
18 free tools · updated regularly
cURL to Fetch Converter
Paste any cURL command and instantly get clean, ready-to-use JavaScript Fetch API code — no install needed.
Open tool →JSONPath Expression Tester & Extractor
Paste any JSON and run JSONPath queries to extract exactly the data you need — with live results, match highlighting, and path suggestions.
Open tool →Git Commit Message Builder & Linter
Craft, validate, and copy perfectly formatted Conventional Commits messages in seconds — with live linting and a character-limit preview.
Open tool →CSS Selector Specificity Comparator & Battle Tool
Paste any CSS selectors and instantly see their specificity scores ranked — know exactly which rule wins the cascade without guesswork.
Open tool →CSS Specificity Calculator & Visualizer
Paste any CSS selectors to instantly calculate their specificity scores, compare them visually, and understand exactly which rule wins the cascade.
Open tool →HTTP Status Code Explorer & Response Simulator
Search any HTTP status code for its official meaning, when to use it, typical response headers, and ready-to-copy code snippets.
Open tool →HTTP Header Analyzer & Builder
Paste raw HTTP headers to get a structured breakdown, plain-English explanations, and security warnings for every header field.
Open tool →PX to REM Converter
Convert pixels to rem and rem to pixels with a custom root font size — for responsive, accessible CSS.
Open tool →HTML Minifier
Compress HTML by removing comments and extra whitespace between tags — with size savings.
Open tool →String Escape / Unescape
Escape text for JSON and JavaScript strings (quotes, newlines, tabs) and reverse it.
Open tool →Diff Checker
Compare two blocks of text line by line and see exactly what was added and removed.
Open tool →Markdown Preview
Write Markdown and see the formatted HTML render live, side by side.
Open tool →Unix Timestamp Converter
Convert epoch time to dates and dates to timestamps, with a live current Unix timestamp.
Open tool →JWT Decoder
Decode a JSON Web Token's header and payload, view claims, and check expiry — privately.
Open tool →Number Base Converter
Convert between binary, octal, decimal and hexadecimal instantly — see all four at once.
Open tool →HTML Entities Encoder & Decoder
Convert special characters to HTML entities and back instantly — escape <, >, &, and quotes.
Open tool →URL Encode & Decode
Percent-encode text for safe use in URLs and decode encoded URLs back to readable text.
Open tool →Base64 Encode & Decode
Convert text to Base64 and decode Base64 back to text instantly, with full UTF-8 support.
Open tool →About Developer Tools
Essential developer utilities — Base64 and URL encoders, JWT decoder, number base converter, HTML entities, timestamp tools and more. All run client-side, so your data stays private.