Developer Tools
Free developer tools for everyday coding tasks — formatting, encoding, testing, and converting — with no signup and nothing to install. Paste messy JSON into the JSON formatter to pretty-print it, or use the JSON fixer to repair broken syntax. Test patterns live with the regex tester, encode and decode base64, or generate MD5 and SHA hashes. Inspect JWT tokens with the JWT decoder, translate cron expressions into plain English, or minify CSS, HTML, and JavaScript before deployment. Convert between CSV, JSON, Excel, Markdown, and HTML, switch number bases, check color contrast for accessibility, or generate QR codes. Front-end developers minify stylesheets and scripts to speed up page loads, convert px values to rem for accessible typography, and estimate gzip sizes before shipping. Back-end developers format SQL queries for readability, generate htpasswd files for basic auth, and inspect webhook payloads. Because everything runs locally in your browser, you can safely paste API responses and tokens without sending them to a server.
Frequently asked questions
How do I format and validate JSON online?
Paste your JSON into the JSON formatter — it pretty-prints the structure and highlights syntax errors with line numbers. If the JSON is broken, the JSON fixer attempts to repair common issues like trailing commas. Your data stays in your browser, so tokens stay safe. It handles large payloads smoothly and can minify JSON too when you need the compact form. A must-have tab for anyone working with APIs daily.
How can I test a regular expression?
Enter your regex pattern and a sample text in the regex tester to see matches highlighted in real time. It shows capture groups and flags errors in your pattern as you type. A quick way to debug validation patterns before putting them in code. Common presets like email and URL patterns are included to start from. Once your pattern works, copy it straight into your codebase with confidence.
How do I decode a JWT token?
Paste the token into the JWT decoder and it instantly shows the header, payload, and signature details — no signup needed. Useful for checking expiry times, scopes, and claims while debugging authentication. Tokens are decoded locally and never leave your device. It also verifies the signature structure and flags malformed tokens. Because decoding is local, even production tokens can be inspected safely.
What does a cron expression like "0 9 * * 1" mean?
Paste it into the cron expression reader for a plain-English translation — in this case, at 9:00 AM every Monday. It also shows upcoming run times. Handy when scheduling jobs and you do not want to misread the syntax. It handles the standard five-field format plus common extensions. Double-checking here prevents jobs that run at the wrong hour — or never at all.
All Developer Tools (35)
Barcode GeneratorFree barcode generator online — create scannable Code 128 barcodes from any text or…Base64 Encoder DecoderBase64 encode and decode online with full UTF-8 support and URL-safe mode. Convert any…Color Converter (HEX/RGB/HSL)Free hex to RGB converter: translate any color between HEX, RGB, HSL, HSV and…Contrast Checker (WCAG)Free contrast checker wcag: test any two colors against WCAG AA and AAA standards.…Cron Expression ExplainerFree cron expression explained: paste any cron schedule for a readable translation. No signup,…CSS MinifierCSS minifier online — remove comments and whitespace to shrink stylesheets safely, with exact…CSV to Excel ConverterCSV to Excel converter — turn CSV text or files into genuine .xlsx spreadsheets…CSV to JSON ConverterCSV to JSON converter — parse CSV files with quoted fields and custom delimiters…Excel Voucher GeneratorGift voucher generator — create numbered gift vouchers with amounts, recipients, and expiry dates,…Fix JSON OnlineFix JSON online — repair trailing commas, single quotes, comments and unquoted keys, then…GZIP Size EstimatorFree gzip size checker: measure the true compressed size of your text, code or…Hash Generator (MD5 / SHA)Free hash generator md5 sha256: create MD5, SHA-256 and SHA-512 digests from text. No…HTML Entity Encoder DecoderHTML entity encoder and decoder online — escape or unescape HTML special characters and…HTML MinifierHTML minifier online — strip comments and collapse whitespace to shrink page size, with…HTML to XML ConverterHTML to XML converter — turn messy HTML into clean, well-formed XHTML/XML with proper…Htpasswd GeneratorFree htpasswd generator: create salted APR1-MD5 password entries for Apache. No signup, runs entirely…JavaScript MinifierJavaScript minifier online — safely shrink JS by removing comments and whitespace, with exact…JSON Formatter & ValidatorFree JSON formatter with no ads — validate, pretty-print and beautify any JSON with…JSON to CSV ConverterJSON to CSV converter online — flatten nested JSON objects and arrays into spreadsheet-ready…JWT DecoderJWT decoder online — inspect header and payload claims, check the signing algorithm and…Markdown to HTMLMarkdown to HTML converter — turn Markdown into clean, safely escaped, ready-to-paste HTML in…Number Base ConverterFree number base converter: translate between binary, octal, decimal and hexadecimal. No signup, runs…PX to REM ConverterFree px to rem converter: turn pixel values into scalable rem units instantly. No…QR Code GeneratorFree qr code generator no signup: turn any text or URL into a scannable…Regex TesterRegex tester online — test JavaScript regular expressions with live match counts, positions and…SQL FormatterFree SQL formatter online: beautify messy queries with one clause per line. No signup,…Text Diff CheckerFree text diff checker online: compare two texts line by line and spot every…Timestamp ConverterFree timestamp converter: turn Unix timestamps into readable dates and back. No signup, runs…URL Encoder DecoderURL encoder and decoder online — percent-encode or decode URLs, query strings and form…UUID v4 GeneratorFree UUID v4 generator — create cryptographically random version 4 UUIDs in bulk, with…UUID v7 GeneratorFree UUID v7 generator (RFC 9562) — time-ordered, sortable, cryptographically random IDs, perfect for…WiFi QR Code GeneratorFree WiFi QR code generator: share your network with a scannable code guests join…XML Formatter & ValidatorFree XML formatter online: validate and pretty-print XML with clean indentation. No signup, runs…XML to JSON ConverterXML to JSON converter — convert XML to JSON and back, with attributes, arrays,…YAML to JSON ConverterFree YAML to JSON converter: turn configs and manifests into valid JSON instantly. No…