Developer Tools

Convert between units of length, weight, temperature, area, volume, speed, time, data, pressure and energy. Enter a value once and see it converted to every other unit in the same category, or swap the direction with one click.

Beautify, minify and validate JSON. Invalid input gets flagged with the exact line and column where the syntax breaks. Compare payload sizes before and after minification, then copy the result or download it as a .json file.

Encode text to Base64 or decode Base64 back to plain text. Switch between Standard (+ and /) and URL-safe (- and _) alphabets depending on where the output will go. Result appears as you type — no button to press.

Generate cryptographically secure UUIDs — up to 100 per click. Choose version 4 (fully random) or version 7 (time-ordered, sortable by creation time). Toggle uppercase or lowercase, with or without dashes. Copy results with one click.

Compute MD5, SHA-1, SHA-256 and SHA-512 hashes for any text — all four at once. SHA algorithms use the browser's native Web Crypto API; MD5 runs through a local implementation. Everything happens on your device.

Encode or decode URLs and query parameters. Two modes: Component encodes everything including ?, & and = (use it for query values), Full URL preserves reserved characters (use it for complete URLs). Result updates as you type.

Convert Unix timestamps to ISO, UTC, local and relative time — and back. Choose seconds or milliseconds, use the quick +/- buttons for hours and days, or paste a whole list of timestamps to convert in one batch.

Paste a JWT and see its header, payload, signature and expiry decoded in one view. Checks whether the token is still valid or has expired. Runs entirely in your browser — nothing is logged, stored or sent anywhere.

Create and sign JSON Web Tokens with HS256, HS384 or HS512 — all locally in your browser via the Web Crypto API. Edit the header, add claims to the payload, enter your secret, and copy the signed token. Your secret never leaves your device.

Generate standard open source licenses — MIT, Apache 2.0, GPL-3.0, AGPL-3.0, LGPL-3.0, BSD-2, BSD-3, ISC, MPL-2.0, Unlicense — with your year, copyright holder and project name filled in. Copy the LICENSE text or download it as a file.

Build a .gitignore file for your stack. Pick from 30+ templates covering languages, frameworks, editors, IDEs and operating systems, or choose a quick preset for Web, Mobile, Backend or Data/ML. Add custom patterns and download the file.

Write Markdown on the left, see the rendered HTML on the right. Supports GitHub Flavored Markdown — tables, task lists, strikethrough, autolinks and fenced code blocks. All output is sanitized with DOMPurify. Download the rendered HTML as a standalone file.

Format messy SQL into readable code or minify it into a single line for logs. Control keyword casing (UPPERCASE, lowercase or Preserve) and indentation level. Comments are kept in Format mode and stripped in Minify mode.

Compress HTML, CSS or JavaScript by removing whitespace and comments. The language is detected automatically. JavaScript uses Terser in its safest mode — no variable renaming, no logic changes. See the size reduction in bytes after minifying.

Pick a color and see it in HEX, RGB, HSL and HSV — all four formats at once. Generate complementary, analogous, triadic, split-complementary and monochromatic palettes. See tints and shades of the current color. Click any swatch to copy it.

Check whether your text and background colors pass WCAG 2.1 AA and AAA. See the contrast ratio, live preview at three text sizes and pass/fail status for normal text, large text and UI components. Swap foreground and background with one click.

Build a full set of meta tags with live previews of how the page will look in Google search and when shared on social media. Fill in title, description, URL, social image, site name, Twitter handle and OG type — copy the whole block and paste it into your head section.

Turn SVG markup into a Data URI for CSS backgrounds or inline HTML. Get ready-to-use snippets in four flavours: URL-encoded CSS background, Base64 CSS background, HTML img tag and raw Data URI. Live SVG preview confirms the rendering before you copy.

Paste a Base64 string and see the decoded image instantly. Accepts raw Base64 or a full data URI — with or without the data:image/...;base64, prefix. Detects PNG, JPEG, GIF, WebP, BMP, SVG, ICO and AVIF from the data URI or the file's magic bytes. Download with the right extension.

Test JavaScript regular expressions with live highlighting. Matches appear as you type. Toggle all six flags — g, i, m, s, u, y — independently. See index, full match and capture groups for every match. Clear error messages for malformed patterns.

Give the generator a few example strings that should match — and optionally some that should not — and get a working regular expression. It analyses the common structure, produces a pattern with a plain-English explanation and validates the result against your negative examples.

Build box-shadows and gradients visually. Add multiple shadow layers, each with its own offsets, blur, spread, color and inset toggle. For gradients, choose linear, radial or conic and add as many color stops as you need. Live preview updates as you adjust.

Turn a single square image into a complete favicon set — 16, 32, 48, 96, 180, 192 and 512 px, covering browsers, iOS and Android. Get a ready-to-use site.webmanifest, an HTML link snippet, and a ZIP archive with all icons ready to drop into your public folder.

Paste or upload a Base64 image and get back a smaller one. Control output format, maximum width and height, and quality — the tool re-encodes the image through the Canvas API. Handy for shrinking inline data URIs in HTML, CSS or JSON payloads.