Programming
Developer tools: JSON, Base64, hashes, UUID, regular expressions and more.
Tools in this category
Base64 encode / decode Encode and decode Base64 with full UTF-8 support — accents and emojis handled correctly. Paste text, copy the result instantly. Free, no sign-up. Diff checker — compare text Compare two texts line by line: additions in green, deletions in red, plus change counters. Runs 100% in your browser, so private text never leaves your device. AI token counter (GPT) Count the tokens in your text for GPT models (o200k and cl100k), plus characters, words and an editable cost estimate. Everything runs in your browser. Color contrast checker (WCAG) Check the color contrast between text and background to WCAG: exact ratio and whether it passes AA and AAA for normal and large text. Free, no sign-up. HEX / RGB / HSL color converter Convert a color between HEX, RGB and HSL in any direction: type any of the three formats and get the other two with a live swatch and one-click copy buttons. Unix timestamp converter Convert Unix timestamps to readable dates in local time and UTC, or any date to seconds and milliseconds. Auto-detects the unit, right in your browser. Crontab expression explainer Translate any 5-field cron (crontab) expression into plain English and preview the next run times. Supports asterisk, */n, lists and ranges. HTML entities encoder / decoder Encode and decode HTML entities: turn < > & quotes and apostrophe into < & and back to plain text. Runs in your browser, free, no sign-up needed. HTML formatter (beautify) Free HTML formatter in your browser: beautify and indent minified or one-line HTML with two spaces so it is readable again, then copy it in a click. JSON formatter & validator Format, validate and minify JSON right in your browser: 2 or 4 space indentation and syntax errors with exact line and column. Free, no sign-up. SQL formatter Free SQL formatter that runs in your browser: uppercase keywords, line breaks before every clause and clean indentation for SELECT, JOIN, WHERE and ORDER BY. XML formatter Format and indent XML right in your browser: turn a messy one-line file into readable code with 2 or 4 spaces, plus minify and copy. Free, no sign-up needed. CSS border-radius generator Generate CSS border-radius with sliders for all 4 corners or an 8-value blob mode. Live preview, a random blob button and one-click copy. Free tool. CSS box-shadow generator Build CSS shadows with sliders for X, Y, blur, spread, color with opacity and inset. Stack several layers, preview live and copy the box-shadow code. Password generator Generate strong random passwords in your browser with cryptographic randomness: length slider, symbols and an entropy strength meter. Free, no sign-up. Meta tags generator (SEO and Open Graph) Generate SEO, Open Graph and Twitter Card meta tags from a simple form. Length counters, safe escaping and one-click copy. No sign-up, runs in your browser. CSS gradient generator Build linear, radial and conic CSS gradients with a live preview, up to 6 color stops, angle control and ready-to-copy code. Free, no sign-up. Hash generator (MD5, SHA-256) Generate MD5, SHA-1, SHA-256 and SHA-512 hashes from any text instantly in your browser, with one-click copy for every result. Free and no sign-up needed. Random number generator Generate unbiased random numbers in your browser with cryptographic randomness: pick a range, how many, and a no-repeats option for raffles and draws. QR code generator Create QR codes for URLs, WiFi or text with custom colors, size and error correction. Generated in your browser and downloadable as PNG or SVG. Robots.txt generator Build a valid robots.txt in seconds: allow or block bots, Allow and Disallow rules, crawl-delay and sitemap. Ready presets, live preview and copy. Slug generator Turn any text into a clean URL slug: lowercase, no accents, spaces and symbols become hyphens. Live preview and one-click copy. Free, no sign-up. UUID generator Generate up to 100 random UUID v4 identifiers in your browser, in lowercase or uppercase, and copy one or all with a single click. Free, no sign-up. JSON to CSV converter Convert a JSON array to a CSV table for Excel and back to JSON for your APIs. Pick the delimiter, escape commas and quotes, then copy or download it. JWT decoder Decode any JWT right in your browser: view the header and payload as JSON, with human-readable exp and iat dates plus an expiry check. No sign-up. Markdown to HTML converter Convert Markdown to HTML in your browser: headings, bold, lists, links and code blocks, with a live preview. Free, safe and no sign-up needed. CSS minifier Minify CSS in your browser: strip comments, spaces and line breaks, collapse to one line and see how many bytes and what percentage you save. Free, no sign-up. HTML minifier Minify HTML in your browser: strip comments and whitespace between tags without breaking pre, textarea, script or style. See the bytes and percentage you save. Regex tester Test regular expressions live: highlighted matches, capture groups and JavaScript flags. Runs fully in your browser, free, private and with no sign-up. Color picker (HEX, RGB, HSL) Convert colors between HEX, RGB and HSL in real time, with a tint and shade palette, complementary color and one-click copy for every value. Free, no sign-up. Text to binary (and binary to text) Convert text to binary and binary back to text with correct UTF-8 for accents and emojis. Shows decimal and hex for each character. Free, no sign-up needed. URL encoder / decoder Encode and decode URLs (percent-encoding): turn spaces and accents into %20, %C3%A9 and back again. Copy the result instantly. Free, no sign-up.