Developer tools
Format JSON, decode tokens, convert timestamps and generate UUIDs or QR codes, all offline in the browser.
Format & convert data
- JSON FormatterPretty-print or minify JSON with 2-space, 4-space or tab indentation and optional key sorting.
- JSON ValidatorCheck whether text is valid JSON and see exactly where it breaks, with line, column and a caret.
- JSON MinifierStrip every unnecessary space and line break from JSON and see how many bytes you saved.
- JSON to CSVTurn a JSON array of objects into CSV for Excel or Google Sheets; nested objects become dot-separated columns.
- CSV to JSONConvert CSV or TSV into a JSON array of objects, with delimiter detection and number/boolean types.
- HTML FormatterBeautify minified or messy HTML with consistent indentation, including inline CSS and JavaScript.
- CSS FormatterUnminify and beautify CSS: one declaration per line, clean indentation, readable media queries.
- JavaScript FormatterBeautify minified or messy JavaScript and JSON-like code with your choice of indentation and brace style.
- XML FormatterPretty-print or minify XML and check that it is well-formed, with the line and column of any error.
- Markdown to HTMLConvert Markdown to clean, sanitised HTML with a live preview, GitHub tables and task lists.
Encode, decode & generate
- Password GeneratorRandom passwords from crypto.getRandomValues, 8 to 64 characters, with the entropy in bits and a strength label.
- Base64 Encode / DecodeEncode text to Base64 or decode Base64 back to text, UTF-8 safe, with a URL-safe option.
- URL Encode / DecodePercent-encode text for URLs (encodeURIComponent or encodeURI) or decode an encoded string.
- JWT DecoderDecode a JSON Web Token's header and payload and see whether it has expired. Signature is not verified; the token stays in your browser.
- UUID GeneratorGenerate 1 to 100 random UUID v4 or time-ordered UUID v7 identifiers with crypto-grade randomness.
- Hash GeneratorMD5, SHA-1, SHA-256, SHA-384 and SHA-512 of text or a file, with HMAC and checksum comparison.
- Unix Timestamp ConverterConvert a Unix timestamp to a date or a date to a timestamp; shows UTC, local time, ISO 8601 and relative time.
- Regex TesterTest a JavaScript regular expression against text with highlighted matches, capture groups and a timeout guard.
QR codes & barcodes
- QR Code GeneratorTurn a URL or text into a QR code and download it as PNG or SVG. Generated locally; nothing is uploaded.
- QR Code with LogoMake a QR code with your logo in the middle, checked in the browser to make sure it still scans.
- Wi-Fi QR Code GeneratorMake a QR code that joins your Wi-Fi network when scanned, with correct escaping of special characters. The password never leaves your device.
- vCard QR Code GeneratorTurn your contact details into a QR code that adds you to a phone's contacts, plus a .vcf file. Built on your device.
- QR Code ScannerRead a QR code with your camera or from a screenshot, and see the content safely before opening any link.
- Barcode GeneratorMake Code 128, EAN-13, UPC-A, Code 39, ITF-14 and EAN-8 barcodes with automatic check digits, and download them as SVG or PNG.
Web & SEO
- Meta Tag GeneratorWrite title, description, Open Graph and X tags with length meters and a Google-style preview.
- Open Graph PreviewPaste a page's tags and see how the link may look on Facebook, X, LinkedIn and WhatsApp.
- Sitemap GeneratorTurn a list of URLs into a valid sitemap.xml with lastmod, changefreq and priority options.
- Robots.txt GeneratorBuild robots.txt with presets (including blocking AI crawlers), validation and a URL tester.
Device tests
- Webcam TestCheck that your camera works before a call: live preview, resolution and frame rate, camera picker, mirror view and snapshot. Nothing is recorded.
- Microphone TestCheck your microphone: live level meter and waveform, clipping warning, echo and noise suppression toggles, and a 5-second recording to play back.
- Keyboard TesterPress every key and watch it light up on a full-size ANSI or ISO diagram, with key codes, rollover count and stuck-key detection.
- Dead Pixel TestFill the screen with solid colours to spot dead, stuck or hot pixels and backlight bleed, with an optional stuck-pixel fixer (opt-in, flashing).
Developer tools that run entirely in the page, so tokens, payloads and API responses stay on your machine: format and validate JSON with line and column errors, flatten JSON to CSV for a spreadsheet, decode a JWT, convert Unix timestamps and test regular expressions.
Encoding and identifiers: Base64, URL encoding and UUIDs. For codes, make a QR code, a Wi-Fi QR code or a barcode, and read one with the QR scanner.