🧑‍💻 Developer tools

34 free Developer tools. Each one runs right in your browser: no sign-up, no watermark, and your files stay on your device.

• 🧾 JSON Formatter & Validator Pretty-print, minify, sort and validate JSON with error lines.
• 📊 JSON to CSV Convert JSON arrays to CSV; nested fields become columns.
• 🔄 CSV to JSON Convert CSV or TSV to JSON, with headers and number types.
• 🔣 Base64 Encode / Decode Encode text to Base64 or decode it back, emoji included.
• 🌐 URL Encode / Decode Encode or decode URLs, and split a link into its parts.
• 🏷️ HTML Entities Encode / Decode Escape < > & " for HTML, or turn entities back into text.
• 🧪 Regex Tester Test patterns live: highlights matches, groups and replacements.
• 🪪 JWT Decoder Decode a JWT and see its claims and expiry in plain dates.
• 🗜️ Code Minifier (JS, CSS, HTML) Shrink JS (Terser), CSS and HTML; see the size saved.
• Ⓜ️ Markdown to HTML Write Markdown, see the preview, copy clean HTML.
• 📐 YAML ↔ JSON Converter Convert YAML and JSON both ways with clear error lines.
• 🎨 Color Converter & Contrast Checker Convert colours between HEX, RGB, HSL, HSV, CMYK; check contrast.
• 🧵 Escape / Unescape String Escape quotes and special characters for code, or turn escaped text back to normal.
• ⏰ Cron Expression Explainer Paste a cron line to see what it means in words and when it will run next.
• 🚦 HTTP Status Codes Every common HTTP status code explained in plain words, searchable by number or word.
• 🧭 What Is My User Agent See your browser’s user agent, version, system and screen size, and parse any user-agent string.
• 🌈 CSS Gradient Generator Make linear, radial or conic CSS gradients with up to 6 colours and copy the code.
• 🔲 Box Shadow Generator Design soft, hard, floating, inner or glowing shadows and copy the box-shadow CSS.
• 🏷️ Meta Tag Generator Create title, description, Open Graph and Twitter card tags, with a Google result preview.
• 🤖 robots.txt Generator Build a correct robots.txt with blocked folders, AI-crawler rules and your sitemap, then test any path.
• ↪️ .htaccess Redirect Generator Turn a list of old and new addresses into 301 redirects, plus https, www and 404 rules.
• 🔐 chmod Calculator Tick read, write and execute boxes to get the chmod number, letters and command, or decode one.
• 🌐 IP Subnet Calculator Find the network, broadcast, mask, wildcard, host range and host count of any IPv4 subnet.
• 🆚 JSON Compare Compare two JSON documents by meaning and list every added, removed and changed value with its path.
• 📰 XML Formatter Beautify or minify XML, check it is valid, and convert XML to JSON or JSON to XML.
• 🧬 JSON to TypeScript, Go and Python Generate TypeScript interfaces, Go structs or Python dataclasses from a JSON sample.
• 🗺️ XML Sitemap Generator Turn a list of page addresses into a valid sitemap.xml with last-changed dates, ready for Google.
• 🖼️ Placeholder Image Generator Make placeholder images of any size and colour with a label, as PNG, JPG, WebP or SVG.
• 📡 API Request Tester Send GET, POST, PUT, PATCH or DELETE requests with headers and a body, and inspect the response.
• 🪄 Code Beautifier Turn minified or messy JavaScript, JSON, CSS, HTML or SQL into neatly indented code; the language is detected for you.
• 🧾 SQL Formatter Format SQL with clean indentation and keyword case for 13 databases, or minify it onto one line.
• ✨ SVG Optimiser Shrink SVG files with SVGO: remove editor junk and metadata, round numbers, merge paths, and compare before and after.
• 📍 What Is My IP See your public IP address (IPv4 or IPv6), approximate location, internet provider and time zone, or look up any IP.
• 🌐 DNS Lookup Look up DNS records for any domain over encrypted DNS-over-HTTPS: A, AAAA, CNAME, MX, TXT, NS, SOA, CAA, SRV and PTR.