Tools
Everything runs locally. Your data never leaves the browser.
JSON Studio
Format, minify, sort, validate with exact error positions, and diff two JSON documents. Runs entirely in your browser.
Timestamp
Convert Unix timestamps and dates both ways, auto-detecting seconds vs milliseconds. Also shows ISO 8601, RFC 2822, relative time, day-of-year, ISO week, and a multi-timezone table.
Regex Lab
Test regular expressions live: highlight hits, list every match with positions and groups, preview replacements, and start from built-in templates for email, URL, IPv4, dates and more.
Encode / Decode
Base64, Base64URL, URL, HTML entities, Unicode escapes and hex — plus JWT decoding with exp / nbf checks. Everything runs locally; tokens never leave the browser.
Text Diff
Line-by-line diff with added and removed rows, plus word-level highlighting. Ignore case or whitespace, and export a standard unified diff in one click.
Hash & Checksum
Compute CRC32, MD5 and SHA-1/256/384/512 at once — for text or a file. Paste an expected checksum and it tells you which one matches.
Generator
Generate UUID v4 / v7, ULID, passwords, random strings and slugs. Passwords show live entropy and strength, with an option to exclude lookalike characters such as O0Il1.
Color & Contrast
Parse hex / rgb / hsl, convert between notations, and compute WCAG contrast with AA / AAA levels. Includes a full 50–900 tint ramp and tells you whether text on a colour should be black or white.
Base & Units
Convert between any bases from 2 to 36 with grouped binary and byte views, plus ten unit categories — length, mass, area, volume, data, time, speed, pressure, energy and temperature — each listing every equivalent at once.
Image Compress
Resize, rotate, flip and convert images (WebP / JPEG / PNG) right in the browser, with an automatic quality search to hit a target file size. Nothing is uploaded — it all runs on a local canvas.
Cron parser
Expand a five-field cron expression into its values and list the next five run times. Ranges, steps, lists and names like JAN or MON are supported, including the DOM/DOW union rule.
Bit workbench
A bit workbench: base conversion, 8/16/32-bit fixed-width views, per-bit inspection and toggling, byte breakdown, popcount plus leading and trailing zero counts, and an IEEE 754 double breakdown.
CSV studio
Parse and build CSV per RFC 4180, including delimiters and newlines inside quotes and doubled quotes for a literal one. Sniffs the delimiter (comma, tab, semicolon, pipe), previews the table, converts to and from JSON.
JWT inspector
Split a JWT into header and payload, flag exp/nbf/iat as expired, not yet valid or fine, and verify or re-sign HS256/384/512 with WebCrypto. Everything runs locally; the token never leaves the page.
Text lab
Counts for mixed Chinese and English text (including UTF-8 bytes, code points and reading time), word frequency and Shannon entropy, naming-style conversion, slug generation, plus one-off line operations: trim, dedupe, sort, number, join.
IP & Subnet Calculator
Unpack an address like 10.0.0.1/24: network, broadcast, usable range, mask and wildcard, binary and hex, plus reserved-range detection. Split a block into smaller subnets, or find the smallest block covering two addresses.
URL Inspector
Split a URL into protocol, host, port, path, query and fragment, edit each part and rebuild it. Query parameters are listed individually so duplicates survive; includes percent encoding and a warning for sensitive parameters.
Date Calculator
Days, weeks and business days between two dates; add or subtract years, months and days; leap year, ISO week, day of year and weekday all at once. Everything is computed at UTC midnight, so local time and DST cannot skew it.
Unicode Inspector
For the same text, code points, grapheme clusters, UTF-8 bytes and display width all differ. This tool lists each code point in hex and decimal, flags combining marks and wide characters, and shows all four normalization forms.
JSON Path Query
Pull nodes out of any JSON with $.a.b, $[0], $[*], $..name and $[?(@.id > 10)]. Results come back as a path list you can copy as values or as JSON. Everything runs in the browser; nothing is uploaded.
Morse code
Convert text to Morse and back: letters, digits, punctuation and prosigns, with the total transmission time and audio playback. Full-width dots and dashes are normalised first.
Roman numerals
Convert between Arabic and Roman numerals from 1 to 3999. Decoding is strict, so IIII or VX are rejected, and the breakdown shows which values a number uses.
HTTP status codes
Look up HTTP status codes by number or keyword: 39 common codes in five classes, each with a one-line note in three languages plus an MDN link.