MDV Tools

63 tools · 0 accounts

Each tool is one HTML file that does one job on your device. The list below is only the finished ones, grouped by catalogue group; a group appears here the day its first tool ships.

Runs on this device Works offline No account No adv

Text

Case converter Upper, lower, title, sentence, camel, snake, kebab, constant. Unicode-aware. Remove duplicate lines Each line once, first or last occurrence, in original order or sorted. Sort lines A–Z, Z–A, natural, by length, shuffle or reverse, with trim, case-fold, blank and duplicate removal. Lorem ipsum Placeholder text in paragraphs, sentences, words or list items, as plain text, HTML or Markdown. Find and replace Replace every match at once, plain text or regular expression, with capture groups and a count. Slugify Fold accents to ASCII, pick a separator, cap the length at a word boundary. Text diff Line-by-line comparison of two blocks of text. Unicode inspector Every code point with its bytes, category, script and hidden-character flags, plus the four normalisation forms. Remove whitespace Tidy doubled spaces, tabs and blank lines, or strip every space so 1 2 3 4 5 reads 12345; no-break spaces are named. Word counter Words, graphemes, bytes, sentences, paragraphs and reading time, live as you type.

Encoding and crypto

Barcode generator Make an EAN-13, UPC-A, EAN-8, Code 128 or Code 39 barcode with the check digit worked out or verified, as SVG or PNG. Base64 Encoder & Decoder Text to Base64 and back, both fields live, with the URL-safe alphabet and 76-column wrapping. Image to data URI Turn an image into a data URI for CSS or HTML, with the size it adds and whether it is worth inlining. Checksum SHA-256, SHA-1 and size for any file, computed locally. Hash generator CRC-32, MD5, SHA-1, MySQL PASSWORD(), SHA-256, SHA-384 and SHA-512 of one string at once, with the broken ones marked as broken. HTML entities Escape text for HTML or turn entities back into characters, with a choice of how much to escape. JWT decoder Header, payload and claims with expiry as a date. Decodes only, never verifies. Password generator Random passwords from the browser crypto API, with length, character sets, and the entropy in bits. QR code generator Turn a link or any text into a QR code with no redirect inside, then download PNG or SVG or copy the image. SSH key generator Make an Ed25519, ECDSA or RSA key pair and take the authorized_keys line and the private key as .ppk, OpenSSH or PEM. TOTP code generator Paste a two-factor secret or otpauth link and read the current code and the next — or make a new secret to test a login. URL Encoder & Decoder Percent-encode or decode text as you type, for a query value, a whole URL or form data, with broken escapes named by position. UUID generator Version 4 random or version 7 time-ordered, up to 1,000 at a time, from WebCrypto. Wi-Fi QR code Make a QR code that joins your Wi-Fi when scanned, for WPA, WEP or open networks, ready to print.

Converters

JSON and CSV converter Turn a JSON array into CSV or TSV with nested objects as dotted columns, or CSV and TSV back into JSON. JSON and YAML converter Convert JSON to YAML or YAML to JSON as you type, with anchors, merge keys and several documents read. Base converter Binary, octal, decimal, hex, any base to 36, exact at any size.

Developer

Chmod calculator Tick the permission bits or type the octal mode, and read the rwx string, the ls listing and what each class may do. Cron expression Read a crontab line in plain English, field by field, with the next runs on this device's clock. Subnet calculator Give an IPv4 address with a prefix or a netmask and read the network, broadcast, host range, wildcard and what kind of address it is. JSON diff Compare two JSON documents by structure and read what was added, removed or changed, with each path. JSON formatter Indent, sort keys, or minify. Reports the exact parse error position. Regex tester Matches highlighted, groups in a table, replace preview and a plain-English reading of the pattern. XML formatter Paste XML and get it indented or minified, with the first error named by line and column.

CSS and design

Clamp calculator clamp() for fluid type and spacing, in rem or px, with slope, intercept and a preview at six widths. PX to REM Convert a length between px, rem, em and pt against your own root size, with a ready scale of the common sizes.

Color

Contrast checker Measure the contrast between two colours against WCAG AA and AAA, and get the nearest shade that passes.

Images and media

Circle crop Round off a picture for an avatar — circle, rounded square or plain square — with transparent corners or a colour behind. EXIF viewer and remover See what a photo carries — camera, serial number, time, place — and download it without, pixels untouched. Favicon maker Turn a picture into a real multi-size favicon.ico and the PNGs phones ask for, with the HTML to paste. Image compressor Compress up to 50 images to WebP or JPEG with a quality slider and a size cap, and compare before and after. Image cropper Drag a selection or type the pixels, hold a ratio, and download the crop. Image converter Convert a picture to PNG, JPEG or WebP, with the size change and what the conversion costs. Image resize Scale to a width or height and re-encode as PNG, JPEG or WebP. Redact an image Draw boxes over what should not be shared and export with them blacked out, pixelated or blurred. Social media cropper Crop to the exact pixel size a post, story, header or link preview wants, and see whether your picture is big enough. Watermark Sign a picture with text or a logo, in a corner or tiled across it, at the opacity and angle you choose.

PDF and documents

Document scanner Set the four corners of a photographed page and take away a flat, white scan as PNG, JPEG or PDF.

Finance

IBAN validator Check an IBAN or a list of them — checksum, country length and parts — without asking any bank.

Numbers and units

Aspect ratio Lock a ratio and solve the missing dimension. Unit converter Convert length, mass, volume, area, speed, temperature, time, data, pressure or energy, exactly, and read every unit of the family at once. Percentage calculator Five percentage questions answered as you type: percent of, what percent, change, increase or decrease, and the value before, in exact decimals. Random number generator Draw whole numbers from any range, with or without repeats, and repeat a draw exactly from a seed when it has to be checked.

Time and date

Age calculator Give a date of birth and read the exact age in years, months and days, with the weekday of the birth and the next birthday. Date difference The time between two dates in years, months and days, in weeks, total days and weekdays, with the end date and clock times optional. Discord timestamp Pick a date, time and zone and copy every Discord timestamp code, or paste a code to read the moment inside it. Time zone converter Type a time the way people write it, like 10am PT or 15:00 CET, and read it in every common zone with summer time counted. Timestamp converter Unix seconds or milliseconds to ISO 8601, local time, ISO week and relative time.

Productivity

Flip a coin Flip a fair coin once or a thousand times, with a running tally and the exact odds of the longest streak. Dice roller Roll d4 to d100, several at once, with advantage, keep and drop, and the exact odds of what you rolled. Random picker Paste a list and pick one or several at random, with tickets per entry and winners kept out between draws. Team generator Split a list of names into random teams, by number of teams or people per team, with sizes never more than one apart. Spin the wheel Put names or choices on a wheel and spin for a winner — equal slices, a fair draw, and winners can come off.

Why there is no signup

Every tool here is a single HTML file with no server behind it. There is nothing to log in to, nothing to upload, and nothing to store. Save a page to your disk and it keeps working — offline, on a plane, in ten years, after this site is gone.

No page loads a font, a script, a stylesheet, or an image from anywhere but its own file, and none of them call the network at all. Read the source to check: a tool is one file and a few hundred lines.

The number in the header is how many tools are finished. More are planned, and none of them is listed before it works — a tool appears here the day it ships, and a group appears with its first tool.

The filter buttons narrow the page to one group. The search box matches both the name of a tool and the sentence under it.