No sign-up or installation. Your input is processed in your browser and is not sent to a server.
Developer
Format, minify, and sort the keys of JSON instantly, keeping large integers and other numbers as written if you choose. Syntax errors are shown with their line, column, and cause. Everything runs in your browser — no data is uploaded.
Text
Compare two texts line by line, see added and removed lines with the changed characters highlighted, and copy a unified diff.
Creative
Create a mirrored kaleidoscope with pointer or arrow-key controls, or let it pick a random pattern, then export it as a PNG at screen size, 1080 px or 2048 px.
Create EAN-13/JAN, EAN-8, UPC-A, ITF-14, Code 128, Code 39, and Codabar (NW-7) barcodes and save them as PNG or SVG. Check digits are calculated or verified automatically, and you can set the narrow bar width and bar height in millimetres for print. You can also lay out many barcodes, one per line or as a numbered series, on a printable A4 or Letter PDF.
Convert colors between HEX, RGB, and HSL, and see them in HSV, CMYK, and OKLCH too, with a color picker, a live preview, and WCAG contrast ratios against white, black, or any text color you choose.
Calculate elapsed, remaining, and active time from start, end, current time, and breaks, or work out the end time from the active time. Also adds and subtracts durations such as 1:30 or 2h 15m and converts them to decimal hours.
Crop an image to any area, rotate it 90°, flip it horizontally or vertically, straighten a tilted photo or scan by up to ±45° (or trace a line to level it), and save it as JPEG, PNG, or WebP. Choose aspect ratios such as 1:1 and 16:9, or sizes for OGP images (1200×630), YouTube thumbnails, icons, and ID photos. Everything runs in your browser.
Convert a Japanese address to English. Prefectures and municipalities are romanized automatically, and the block, building and room are put in English order, with a field-by-field view for overseas forms and the phone number written from +81.
Sort a one-item-per-line list ascending, descending, reversed, or shuffled, and remove duplicate and blank lines. Spreadsheet tables and CSV can be sorted by a chosen column with the header line kept on top. Can also list only repeated or only unique lines and count how often each line appears.
A browser-only 30-second typing game that shows CPM, positional accuracy, where you mistyped, and your best round this visit.
A browser-only memory game where you flip cards to find matching pairs across three board sizes, alone or with two players on one screen.
Create a mirrored kaleidoscope with pointer or arrow-key controls, or let it pick a random pattern, then export it as a PNG at screen size, 1080 px or 2048 px.
Unify mixed list markers into -, •, 1., (1), a) and more, and renumber the items. Levels are read from the indentation and each level gets its own marker. Also converts to Markdown or HTML lists, removes markers, and joins wrapped lines.
See how an image or a set of colors looks with protanopia, deuteranopia, tritanopia, or achromatopsia, side by side. Lower the severity to approximate color weakness, and find pairs of HEX colors that become hard to tell apart. Everything runs in your browser.
Paste docker run commands and get a compose.yaml. Reads every docker run option, including ports, environment, volumes, networks, health checks and GPUs, merges several commands into one file, rewrites $(pwd) and $ for Compose, and flags options Compose cannot express.
Understand positional notation and manual conversion, then verify results while handling prefixes, invalid digits, negative values, and large integers.
Reformat only insignificant whitespace in valid JSON, then verify strings, numbers, Unicode, escapes, and property-order assumptions.
Understand JWT headers, payloads, and signatures, why decoding does not establish validity, and how to inspect tokens safely.
