Developer & data
Format, convert and inspect the data structures you work with every day.
JSON Formatter & Validator
Pretty-print, validate and minify JSON with 2/4-space or tab indent and clear line/column errors — formatted live in your browser, nothing uploaded.
CSS Minifier
Shrink CSS with a real parser (clean-css), not a fragile regex — comments and whitespace gone, while strings, data-URIs and calc() spacing stay byte-exact. Shows real byte savings, in your browser, nothing uploaded.
JavaScript Minifier
Shrink JavaScript with a real parser (Terser), not a fragile regex — comments and whitespace gone, locals mangled, while strings, template literals and regex stay byte-exact. Shows real byte savings, in your browser, nothing uploaded.
SVG Minifier
Optimize SVG with SVGO (the engine behind SVGOMG), not a fragile regex — comments, editor metadata and whitespace gone, while your path data, inline CSS and text stay intact. Live before/after preview and real byte savings, in your browser, nothing uploaded.
JSON to TypeScript
Paste a JSON sample and generate TypeScript interfaces live — nested objects become their own named interfaces, arrays infer their element type. In your browser, nothing uploaded.
CSV ⇄ JSON Converter
Convert CSV to JSON and JSON back to CSV live, with correct handling of quoted fields, embedded commas/newlines and semicolon or tab delimiters — converted in your browser, nothing uploaded.
Markdown Table Generator
Build GitHub-Flavored-Markdown tables in an editable grid with per-column alignment and a live preview — or paste TSV/CSV/Markdown and edit it back. Pipes escaped correctly, in your browser, nothing uploaded.
YAML ⇄ JSON Converter
Convert YAML to JSON and JSON back to YAML live, with key order preserved, nested maps, lists and block scalars handled, 2/4/tab indent and clear parse errors — converted in your browser, nothing uploaded.
Regex Tester & Debugger
Test regular expressions live — highlight every match, inspect capture groups with offsets, preview .replace() output and toggle the g/i/m/s/u/y flags. In your browser, nothing uploaded.
Regex Railroad Diagram
Draw any JavaScript regex as a railroad diagram with a plain-English explanation, live match tester and replace preview — handles named groups, lookbehind and \p{…}. Export SVG/PNG; nothing uploaded.
Fix Text Encoding (Mojibake)
Repair garbled text like é and ’ back to é and ’ — reverses UTF-8/Windows-1252 double-encoding (and legacy CJK mis-decodes) live, with an honest confidence rating and a step-by-step explanation. In your browser, nothing uploaded.
Unicode Inspector
Reveal invisible characters — zero-width spaces, bidi controls (the Trojan-Source risk), soft hyphens — and flag confusable homoglyphs and mixed-script text, then strip them with a full audit. In your browser, nothing uploaded.
JWT Decoder & Inspector
Decode a JSON Web Token's header and payload to pretty JSON, humanize the exp/iat/nbf dates and read a valid/expired status — decoded in your browser, nothing uploaded. Signature not verified.
Cron Expression Helper
Translate a cron expression into plain English and preview the next 8 fire times in UTC and your local timezone — live, with a per-field breakdown. In your browser, nothing uploaded.
Cron Dialect Translator
Translate a cron expression between Unix (5-field), Quartz (6/7-field) and AWS EventBridge dialects with every lossy gotcha flagged — day-of-week numbering, the ? token, seconds and year fields — plus plain-English readings and a next-5-runs preview. In your browser.
Chmod Calculator
Unix file permissions three ways — checkbox grid, octal (755, 4755) and symbolic (rwxr-xr-x) — synced live with setuid/setgid/sticky bits and a copy-ready chmod command. In your browser.
Text Diff Checker
Compare two blocks of text and see added, removed and unchanged lines highlighted line by line — computed live in your browser, nothing uploaded.
JSON Diff — Semantic Compare
Structurally diff two JSON documents by path — ignores key order and whitespace, reports added, removed and changed values with type-mismatch flags. In your browser, nothing uploaded.
env-diff — .env Compare & .env.example
Compare two .env files key by key — missing, extra and differing keys, duplicates and unparsed lines — with values masked by default, and generate a safe-to-commit .env.example. In your browser, nothing uploaded.
graphql-sdl-diff — Schema Changelog
Paste two GraphQL SDL schemas and get a PR-ready changelog with every change graded breaking, dangerous, review or safe — powered by a vendored graphql-js. In your browser, nothing uploaded.
lockfile-diff — Lockfile Upgrade Summary
Paste two lockfiles — npm package-lock.json, pnpm-lock.yaml or yarn.lock, auto-detected — and get a semver-classified major/minor/patch upgrade summary with direct-vs-transitive badges. In your browser, nothing uploaded.
json-schema-compat — Breaking-Change Checker
Paste the old and new version of a JSON Schema and get an honest verdict — compatible, breaking, or needs manual review — with every change listed by JSON-pointer path. In your browser, nothing uploaded.
sourcemap-unmin — Stack Trace De-minifier
Paste a minified V8 stack trace plus its .map files and get original file, function and line:column back per frame — with an honest reason whenever a frame can't be mapped. In your browser, nothing uploaded.
gitignore-explain — Why Is This Path Ignored?
Paste a .gitignore and a list of paths — every path gets an ignored / not ignored / re-included verdict with the exact deciding line, using real git semantics golden-tested against git check-ignore. In your browser, nothing uploaded.
CODEOWNERS Resolver — Who Owns This File?
Paste a GitHub CODEOWNERS file and a list of paths — every path resolves to its reviewer(s) with the exact deciding line (last-match-wins), plus warnings for the !, [ ] and escaped-# syntax GitHub silently ignores. In your browser, nothing uploaded.
Number Base Converter
Convert between binary, octal, decimal, hex and any base 2–36 — or 2–62 with case-sensitive digits (0-9 A-Z a-z) — live and BigInt-safe for huge integers, with a bit-length view and digit grouping. In your browser, nothing uploaded.
SHA Hash Generator
Compute SHA-1, SHA-256, SHA-384 and SHA-512 hashes of text or a local file to verify checksums and integrity — hashed in your browser, nothing uploaded.
.htpasswd Generator
Build an Apache or nginx username:hash credential line with bcrypt (recommended) or apr1 (Apache-MD5) — hashed in your browser, the password never sent anywhere.
Base64 Encoder / Decoder
Encode text to Base64 or decode it back, with full UTF-8 support, a URL-safe option and live byte counts — converted in your browser, nothing uploaded.
Image to Base64 Converter
Turn an image into Base64 — raw string, data: URI, HTML and CSS snippets, each copy-ready — or decode Base64 back to a viewable, downloadable image. Nothing is uploaded.
URL Encoder / Decoder
Percent-encode text for a URL or decode it back, with a Component vs Full-URL scope toggle and full UTF-8 support — converted in your browser, nothing uploaded.
HTML Entity Encoder / Decoder
Escape text into HTML entities or decode them back — the five markup characters as named entities, or all non-ASCII as numeric (decimal/hex). Real WHATWG set, unknown entities left untouched. Nothing uploaded.
UTM Campaign URL Builder
Build a Google Analytics campaign link from your utm_ tags — live, correctly encoded, merged with any existing query string. Paste a link to parse its tags back. In your browser, nothing stored.
Slug Generator
Turn a title — or a whole list, one per line — into clean lowercase URL slugs, live. Real Unicode accent-folding (Crème Brûlée → creme-brulee), hyphen or underscore, word-boundary length cap. Nothing uploaded.
Markdown Previewer
Write GitHub-Flavored Markdown and see the sanitized HTML render live — headings, tables, task lists and code blocks. Copy the HTML or download the .md. In your browser, nothing uploaded.
HTML to Markdown
Paste HTML and get clean GitHub-flavored Markdown live — headings, links, lists, tables, code and strikethrough. Copy it or download the .md. In your browser, nothing uploaded.
Open-Source Libraries
17 free MIT-licensed, zero-dependency JavaScript libraries for Node.js — weather math, geo and astronomy calculations and small dev utilities, published on npm with TypeScript types.
Text & writing
Count, transform and fill in copy for drafts, posts and mock-ups.
Word & Character Counter
Count words, characters, sentences and reading time as you type, with live social-media limits and keyword density — all in your browser.
Text Case Converter
Convert text to UPPERCASE, Title Case, Sentence case, camelCase, PascalCase, snake_case, kebab-case, CONSTANT_CASE, dot.case and more, live — copy any one with a click. In your browser, nothing uploaded.
Remove Duplicate Lines
Deduplicate any list live — case-insensitive and trim options, keep first or last occurrence, optional A→Z sort, and line counts. Paste or open a .txt file; nothing is uploaded.
Find & Replace Text
Find and replace live with a match count and highlighted preview — plain mode treats special characters literally (whole-word, case options) or full regex with $1 group references. Paste or open a .txt file; nothing is uploaded.
Lorem Ipsum Generator
Generate placeholder text — paragraphs, sentences, words or list items — with a live word count, an optional classic “Lorem ipsum…” opener and HTML output. In your browser, nothing uploaded.
Subtitle tools
Shift, resync & convert SRT/VTT — files never leave your browser.
Generators
Create passwords, IDs, QR codes, favicons and share-card tags on demand.
Password Generator
Create strong random passwords and memorable passphrases with a live entropy meter — generated in your browser, never sent anywhere.
UUID Generator
Generate random UUID v4, time-ordered v7 or Nil UUIDs in bulk with uppercase, no-hyphen and brace options — created in your browser with crypto-grade randomness, nothing uploaded.
QR Code Generator & Reader
Make QR codes for links, text, WiFi and contact cards and save as PNG or SVG — or read a QR back out of an image. All in your browser, nothing uploaded.
Favicon Generator
Turn an image, .svg, letter or emoji into a full favicon package — a real multi-size .ico, PNGs, apple-touch icon, web manifest, an icon.svg vector (letter marks and .svg uploads), a Safari pinned-tab mask-icon for letter marks and paste-ready HTML. Nothing uploaded.
Open Graph & Card Generator
Build Open Graph and Twitter Card meta tags from a form and preview the Facebook, LinkedIn and X cards live, then copy the tags — all in your browser, nothing uploaded.
Image & PDF
Shrink, resize and clean up images and documents right on your device.
Image Compressor & Resizer
Shrink and resize JPEG, PNG and WebP images with a live quality slider and real before/after sizes — compressed in your browser, nothing uploaded.
PDF Compressor
Shrink scanned and image-heavy PDFs in your browser with real before/after sizes — tune quality and resolution live. Nothing is uploaded.
Merge & Split PDF
Combine several PDFs into one and reorder them, or extract page ranges (1-3,5,8-10) from a PDF — entirely in your browser, nothing uploaded, unlike iLovePDF or Smallpdf.
Split PDF
Split a PDF into separate files by page range — type 1-3, 5, 7-end and each part becomes its own PDF with its own download. Built entirely in your browser, nothing uploaded.
Watermark PDF
Stamp CONFIDENTIAL, DRAFT or any text across PDF pages — diagonal, centered or bottom-right, with opacity, size, color and page-range control. Nothing uploaded.
Add Page Numbers to PDF
Stamp page numbers onto a PDF — bottom-center, corners or top-right, as 1, Page 1 or Page 1 of N, with a start-at offset and page-range control. Nothing uploaded.
Organize PDF
Reorder, rotate and delete PDF pages with per-page thumbnails and buttons — rotation is lossless, and the rebuilt file downloads straight from your browser. Nothing uploaded.
PDF to JPG / PNG Converter
Turn every PDF page into a JPG or PNG image at 72, 150 or 300 dpi with a live quality slider — per-page previews and downloads, entirely in your browser, nothing uploaded.
JPG to PDF Converter
Combine JPG and PNG images into one PDF — reorder pages, pick A4, Letter or auto-fit and a margin, and download. Converted entirely in your browser, nothing uploaded.
Invoice Generator
Build an invoice with line items, tax and discounts, then download it as a clean PDF — exact integer-cents math, live totals, no signup, and your data never leaves your browser.
Number to Words
Spell a number in English words — cardinal (one thousand two hundred thirty-four), currency/cheque form (… Dollars and Fifty Cents), or ordinal (twenty-first). BigInt-exact into the quintillions, live, nothing uploaded.
EXIF Viewer & Metadata Remover
See the camera and GPS location data hidden in a photo, then download a copy with all metadata stripped — read and cleaned in your browser, nothing uploaded.
EXIF Viewer
Drop a JPEG or TIFF to read its hidden EXIF metadata — camera, lens, exposure, date taken, orientation and GPS location — in a clear grouped table. Parsed in your browser, nothing uploaded.
Image Format Converter
Convert an image between PNG, JPG and WebP in your browser — pick the format and keep or flatten transparency onto a background. Nothing is uploaded.
Image Resizer
Resize JPG, PNG and WebP to exact pixels, a percentage or a longest-side target — batch files with an aspect-ratio lock, never crops. All in your browser, nothing uploaded.
Crop Image
Crop JPG, PNG or WebP with a draggable selection or exact X, Y, width and height in pixels — 1:1, 4:3, 16:9 and 9:16 presets, keep or convert the format. Nothing is uploaded.
SVG to PNG Converter
Paste SVG markup or drop a .svg file and download a PNG at 1×, 2×, 4× or an exact width — transparency preserved, with honest warnings when external images or fonts would render blank. Nothing is uploaded.
Aspect Ratio Calculator
Simplify any width × height to its exact ratio (1920×1080 → 16:9) with an honest ≈ label for near-misses, solve a missing dimension at a locked ratio, or drop an image to read its size.
Color & design
Convert color values, check accessible contrast, and generate the CSS for shadows, gradients, layout and animation.
Color Converter & Picker
Pick a color and convert it between HEX, RGB, HSL and HSV with live sliders, a WCAG contrast checker and tint/shade swatches — all in your browser, nothing uploaded.
WCAG Contrast Checker
Check the contrast ratio between two colors and get instant AA/AAA pass/fail for normal text, large text and UI components, with a live preview — all in your browser, nothing uploaded.
Color Palette Extractor
Drop an image and pull out its 6–8 dominant colors as HEX, RGB and HSL, plus a ready-to-paste :root CSS variables block — median-cut quantization in your browser, nothing uploaded.
Color Blindness Simulator
See how an image or palette looks with protanopia, deuteranopia, tritanopia and total color blindness — the published Machado 2009 model applied in linear light, in your browser, nothing uploaded.
CSS Box-Shadow Generator
Build layered CSS box-shadows visually — stack multiple shadows with offset, blur, spread, color and inset, preview live on any background, and copy the exact value — all in your browser, nothing uploaded.
CSS Button Generator
Design a button visually — colors, padding, font, border, radius, shadow and a hover state with a transition — then copy ready-made .btn and .btn:hover rules. Hover the live preview to test it, all in your browser.
CSS Filter & Backdrop-Filter Generator
Drag sliders for blur, brightness, contrast, grayscale, hue-rotate, invert, opacity, saturate, sepia and drop-shadow, preview live, and copy the exact filter or backdrop-filter CSS — with an honest note on the glassmorphism difference, all in your browser.
Glassmorphism Generator
Composite the frosted-glass effect visually — tune blur, tint, fill opacity, saturation, corner radius and border over an adjustable busy background, and copy a ready CSS block with both backdrop-filter and the -webkit- prefix. Honest browser-support notes, all in your browser.
Neumorphism Generator
Build the soft-UI (neumorphism) effect from a single surface color — the tool derives the matching light highlight and dark shadow, emits the dual box-shadow for flat, concave, convex or pressed shapes over a background that shares the surface color, and copies ready CSS. Runs entirely in your browser, free, no sign-up.
CSS clip-path Generator
Pick a polygon, circle, ellipse or inset shape, drag the vertices and handles on a live preview, fine-tune every coordinate as a percentage, and copy the exact clip-path value — all in your browser, nothing uploaded.
CSS Text-Shadow Generator
Build layered CSS text-shadows visually — stack multiple shadows for outlines and neon glows, tune offset, blur, color and opacity on live text at any size and background, and copy the exact value — all in your browser.
CSS Gradient Generator
Build linear and radial CSS gradients visually — add multi-stop colors with positions and opacity, spin the angle, preview live, and copy the exact linear-gradient() or radial-gradient() value, all in your browser.
CSS Border-Radius Generator
Round every corner independently or link them, switch on the elliptical x / y form for squircles and blobs, preview live, and copy the shortest correct border-radius shorthand — all in your browser, nothing uploaded.
CSS Flexbox Generator
Build a flexbox layout visually — set flex-direction, wrap, justify-content, align-items, align-content and gap, add or remove items, preview live in a real flex container, and copy the exact container CSS — all in your browser.
CSS Grid Generator
Build a CSS grid template visually — choose column and row counts, size each track in fr, px or auto, tune the row and column gap, preview a real grid live, and copy the exact grid-template CSS — all in your browser.
CSS cubic-bezier() Generator
Shape a CSS easing curve by dragging its two control points, load the ease / ease-in / ease-out presets, feel the motion in a live animation, and copy the exact cubic-bezier() timing function — all in your browser.
CSS Animation Generator
Build a CSS @keyframes animation visually — add percentage steps, set transform, opacity and background at each one, tune duration, easing, delay, iteration-count (including infinite), direction and fill-mode, watch it loop live, and copy the exact keyframes block and animation shorthand — all in your browser.
CSS Loader Generator
Pick from a curated gallery of nine pure-CSS loading spinners — ring, dual-ring, pulse dots, bars, ripple, flip, orbit and more — tune the colour, size, speed and thickness on a live preview, and copy the JavaScript-free HTML and CSS — all in your browser.
CSS Transform Generator
Stack translate, scale, rotate, skew and 3D rotateX/rotateY/perspective into one transform, reorder the functions live because the order changes the result, preview on a real element, and copy the exact value — all in your browser.
CSS clamp() Calculator
Turn two viewport breakpoints and two sizes into one fluid clamp() value for type or spacing — in px or rem, with the exact vw coefficient and constant shown and a live viewport slider that previews the interpolation, all in your browser.
Sky & environment
Map the night sky and work out sun, moon, weather and geographic facts.
Star Map Generator
Create a custom star map of the night sky for any date and place — a keepsake for birthdays, weddings and anniversaries.
Sunrise & Sunset Calculator
Enter any latitude, longitude and date to get sunrise, sunset, solar noon, day length and civil twilight times — computed live with the NOAA solar algorithm, on the IANA time zone you pick. In your browser, no key, nothing uploaded.
Moon Phase Calculator
See the Moon's phase, illuminated percentage and age in days for any date and time, the dates of the next new and full moon, and — with a latitude and longitude — that day's moonrise and moonset, plus where to point: the Moon's compass azimuth and its altitude in whichever convention you want — geometric, or apparent with atmospheric refraction added. Optional fields let you set your own horizon: your height above sea level, and the angle your skyline stands above eye level at moonrise and at moonset. Drawn live from Meeus' lunar algorithms, in your browser.
Air Quality Index (AQI) Calculator
Enter PM2.5, PM10, ozone, CO, SO₂ or NO₂ concentrations and get the US EPA Air Quality Index live — the overall AQI, the driving pollutant and its color-coded category with health guidance. In your browser, nothing uploaded.
Distance & Bearing Calculator
Enter two lat,lon coordinates and get the great-circle distance in km, miles and nautical miles, the initial and final bearing with a compass heading, and the midpoint — live, WGS-84 accurate. In your browser, nothing uploaded.
WeatherHack
Current conditions, hourly and 7-day forecast for any city — with rain chance, wind and humidity.
Time & numbers
Convert timestamps and units, calculate ages, percentages and VAT, and plan IPv4 subnets.
Unix Timestamp Converter
Convert epoch time to a human date and back — live current Unix time, seconds/ms auto-detect, plus UTC, ISO-8601, RFC-2822 and relative time. In your browser.
Time Zone Converter
Convert a date and time from one zone to up to 5 others at once — day-shift indicator, the real UTC offset for that exact instant and the zone abbreviation, live from your browser's IANA database.
Age Calculator
Find your exact age in years, months and days from any birth date — plus totals in weeks, days and hours, the weekday you were born on, and a next-birthday countdown. In your browser.
Unit Converter
Convert length, mass, temperature, volume, area, speed and data units — cm to inches, kg to lbs, °C to °F — with the result updating live as you type.
VAT Calculator
Add VAT to a net price or remove it from a gross total — net, VAT and gross live at any rate, exact to the cent, with gross→net divided out correctly (not subtracted).
Percentage Calculator
All four percentage questions on one page — X% of Y, X as a percent of Y, percent change between two numbers, and increase/decrease by a percent — live as you type, with exact integer math and honest rounding.
Date Duration Calculator
Duration between two dates in years, months and days plus totals; add or subtract days, weeks, months or years with month-end clamping; and count Mon–Fri business days. Timezone-safe, no daylight-saving off-by-one.
Loan Calculator
Get a loan's monthly payment, total interest and a full amortization schedule from the principal, rate and term — built in exact integer cents so the balance closes at zero, with a copy-as-CSV export. In your browser.
IP Subnet Calculator
Enter an IPv4 address and CIDR prefix and read the whole subnet live — network, broadcast, first/last usable host, host count, netmask, wildcard and the network in binary/hex. In your browser, nothing uploaded.
More tools coming
New free utilities are added regularly. Bookmark Polyatic and check back.