Tools
86 browser-only utilities. Nothing you type is uploaded β it all runs in your tab.
Encoding
5 tools
Base64 encoder / decoder
Convert text to and from Base64. Runs entirely in your browser β nothing is uploaded.
URL encoder / decoder
Percent-encode and decode query strings and path segments. Browser-only.
ROT13 & Caesar cipher
Apply ROT13, an adjustable Caesar shift or Atbash to text with a live preview, all computed locally in the page.
Base32 encoder / decoder
Encode text to RFC 4648 Base32 or decode it back, with optional padding and tolerant input handling. Runs locally.
Text to hex converter
Convert text to hex bytes and back, with UTF-8 handled correctly. Runs locally in your browser.
Hashing
3 tools
Hash & checksum
Compute MD5, SHA-1, SHA-256, SHA-384, SHA-512 of text using your browser. No upload.
File checksum
Drop a file to compute its SHA-256, SHA-1 and MD5 digests locally β the file never leaves your device.
Hash identifier
Work out what a hash probably is from its length, alphabet and prefix. Nothing leaves your browser.
Data
2 tools
Text
11 tools
Case converter
Convert identifiers between camelCase, snake_case, kebab-case, PascalCase, and CONSTANT_CASE.
Regex tester
Test a regular expression against sample text and see every match and capture group, live.
Text statistics
Count characters, words, lines, sentences and reading time as you type.
URL slug generator
Turn a title into a clean, lowercase, hyphenated URL slug β one per line.
Markdown preview
A small, safe Markdown renderer: headings, bold, italic, code, links, lists and quotes.
Sort & dedupe lines
Sort lines alphabetically, numerically or by length, optionally removing duplicates and blanks.
Text diff
Compare two blocks of text line by line and highlight what was added, removed or unchanged.
Word & character frequency
Count word and character frequency, rank the top results and optionally ignore case or drop stop words, all locally.
Pattern extractor
Pull every email address, URL, IPv4 address, number and date out of pasted text, deduplicated. Runs locally.
Unicode code point inspector
See the code point, UTF-8 bytes and escape for every character in a string, including emoji. Nothing is uploaded.
Find and replace
Find and replace across text with regular expressions and capture groups, with every match shown before anything changes.
Generators
4 tools
UUID generator
Generate RFC 4122 version 4 UUIDs using your browser's cryptographic random source.
Password generator
Create strong random passwords locally, with a rough entropy estimate. Nothing is stored or sent.
Lorem ipsum generator
Generate placeholder paragraphs, sentences or words for mockups and layouts.
Random picker
Pick random items from a list, roll dice, or flip a coin β useful for standups, tests and decisions.
Date & time
4 tools
Timestamp converter
Convert between Unix timestamps (seconds or milliseconds), ISO 8601 and your local time.
Date difference
How long between two moments, expressed in years/months/days plus totals, and counting weekdays.
Time zone converter
Convert a date and time between world time zones using your browser Intl data - no network call is made.
Seconds to duration converter
Convert seconds into days, hours, minutes and seconds, and parse a duration back into seconds.
Numbers
9 tools
Number base converter
Convert between binary, octal, decimal and hexadecimal, with bit length and byte view.
Unit converter
Convert length, mass, temperature, area, volume, speed and data sizes without leaving the page.
Percentage calculator
Four everyday percentage questions in one place: of, is-what-percent, change, and reverse.
Number formatter
Format numbers with thousands separators, fixed decimals, percentages or compact notation.
Numbers to English words
Spell an integer or decimal out in English words, optionally as currency such as dollars and cents, with no network call.
Bitwise calculator
Bitwise AND, OR, XOR, NOT and shifts with the result in binary, octal, decimal and hex plus a bit grid, all locally.
Roman numeral converter
Convert Roman numerals to integers and back again, with strict validation in both directions, computed in your browser.
Byte size converter
Convert between bytes, KB, MB, GB, TB and their binary KiB, MiB and GiB equivalents, showing both conventions locally.
Statistics calculator
Mean, median, mode, variance, standard deviation and quartiles for a list of numbers. Runs in your browser.
Design
8 tools
Color converter
Convert a colour between HEX, RGB and HSL, with a live swatch and a contrast check.
Colour palette builder
Generate tints, shades and a complementary colour from one base colour, with copyable hex values.
px - rem converter
Convert between pixels and rem at a chosen root font size, as used for accessible CSS sizing.
Aspect ratio calculator
Work out matching dimensions for a target ratio, and see the CSS to keep the box from shifting.
CSS gradient builder
Build a linear or radial CSS gradient with colour stops, a live preview and copyable CSS, all computed locally.
Box shadow builder
Design a CSS box-shadow with offsets, blur, spread, colour and inset, previewed live and generated locally.
CSS clamp() generator
Turn a min and max font size into a fluid clamp() value, with the maths shown and a live preview.
Colour contrast checker
Check a text and background pair against the WCAG 2 ratios for normal and large text, and get the nearest passing shade of the same hue.
Security
3 tools
JWT decoder
Decode a JSON Web Token's header and payload. Decoding only β it does not verify the signature.
AES encrypt / decrypt
Encrypt text with a passphrase using AES-GCM and PBKDF2, entirely in your browser. Decrypt with the same passphrase.
TOTP code generator
Generate the 6 or 8 digit 2FA code for a secret, and check a code you were given. Everything stays in the tab.
Code
3 tools
CSS & HTML minifier
Strip comments and redundant whitespace from CSS or HTML. Safe, local, and reversible only from your original copy.
JSON to TypeScript
Generate TypeScript interfaces from a JSON sample, merging array element shapes into a single type.
String escape / unescape
Escape text into a JSON/JavaScript string literal, or turn an escaped literal back into readable text.
Web
11 tools
Query string parser
Break a URL's query string into a table, and rebuild a query string from key/value pairs.
HTML entity encoder
Escape or unescape HTML entities so text can be displayed safely inside markup.
Keyboard event inspector
Press any key to see the event.key, code, keyCode and modifier state a page actually receives.
URL parser
Split a URL into protocol, host, port, path, hash and every query parameter with decoded values, using local parsing only.
HTTP status codes
Look up any HTTP status code by number or name, grouped by class with reason phrases and a short meaning.
MIME type lookup
Find the MIME type for a file extension or a filename, or work backwards from a type, with no server involved.
Meta tag generator
Generate title, description, canonical, Open Graph and Twitter card tags, with length warnings.
robots.txt generator
Build a robots.txt and check one you already have for the mistakes that silently deindex a site.
IPv4 subnet calculator
Work out the network, broadcast, host range and mask for any CIDR block, with the binary that shows where the split falls.
Content-Security-Policy builder
Assemble a Content-Security-Policy from its directives and get the header line, the meta tag, and a warning about what the policy does not cover.
User-Agent parser
Read a User-Agent string into browser, engine, operating system and device type, and see everything this browser admits about itself.
DevOps
2 tools
Image
5 tools
Image resizer
Resize an image in the browser and download the result, with adjustable quality for JPEG and WebP.
Image format converter
Convert PNG, JPEG, WebP, AVIF, BMP or ICO in bulk, with quality and a background for transparency. Runs in your browser.
Favicon generator
Turn one square image into a favicon.ico plus the PNG sizes browsers and phones ask for, and copy the markup.
Placeholder image generator
Generate an SVG or PNG placeholder of any size, colour and label, and copy the markup straight into your layout.
Image colour extractor
Pull the dominant colours out of a photo or a logo and get their hex codes, plus the average colour and the tints at both ends.
Converters
11 tools
YAML to JSON converter
Convert between YAML and JSON in the browser, handling nested maps, lists, quoted strings and comments locally.
XML to JSON converter
Turn XML into JSON and back with the browser's own parser, keeping attributes and repeated tags intact locally.
CSV to Markdown table
Convert CSV with quoted fields into a GitHub-flavoured Markdown table, with delimiter detection that runs offline.
HTML table to JSON
Paste HTML markup and read the first table back as JSON or CSV, with colspan and rowspan expanded locally.
SQL formatter
Indent a SQL statement and uppercase its keywords with a light formatter that runs entirely in your browser.
dotenv file checker
Parse a .env file, flag duplicate keys and malformed lines, then emit a sorted KEY=VALUE list without uploading.
INI to JSON converter
Read INI sections and keys as JSON, or write JSON back to INI text, reporting duplicate keys and comments locally.
JSONPath query tester
Run a JSONPath style query such as $.a.b[0] against a JSON document and list every matching value and path.
Data URI encoder
Encode text or a URL as a data URI and decode one back to text, with MIME type and base64 options, fully offline.
CSV to SQL INSERT
Turn CSV into INSERT statements, with quoting, NULL handling and optional type sniffing. Local only.
HTML table generator
Turn pasted CSV or TSV into semantic HTML table markup, with a caption, a header row and the scope attributes a screen reader needs.
GitHub
5 tools
.gitignore generator
Generate a merged .gitignore for languages, editors and operating systems - all processing happens locally.
Licence picker
Pick an open source licence and get ready-to-paste text with the current year and your name filled in, generated locally.
GitHub Actions cron helper
Describe a cron expression in plain English and see the next fire times; everything is computed locally in your browser.
Semantic version checker
Parse, compare and range-check semantic versions with caret and tilde support, evaluated entirely in your browser.
Conventional commit builder
Build a Conventional Commits message and lint one you already wrote, including subject length and breaking changes.