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52 tools that run in your browser. Nothing you paste here leaves your device.
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JSONUUID, ULID & NanoIDBase64URLHTML entitiesJWTHash (MD5, SHA)Text diffRegexCase and linesLorem ipsumUnix timestampColorsNumber basesDNI & NIECIF (Spanish company tax ID)IBANLicense platesSocial Security numberTest cardsSpanish phone numbersSWIFT / BICEAN & ISBNPostal codesMock dataUnitsCurrencypx to remchmodFile sizesSpin the wheelShuffle listTeamsDice & coinSpanish VATIRPF withholdingPercentagesRule of threeBusiness daysPasswordsQR codeSlugJSON, YAML & CSVJSON diffMarkdowncURL to fetchQuery stringHTTP status codesCronUser-AgentSemverCIDR subnetsStatus
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Generators
Identifiers, placeholder text and test data.
- UUID, ULID & NanoIDGenerate up to 500 UUID v4 or v7, ULID or NanoID at once and check any identifier: version, validity and the date it carries.
- Lorem ipsumGenerate Lorem ipsum placeholder text by paragraphs, sentences or words, starting with “Lorem ipsum dolor sit amet” or not, as plain text or HTML <p>.
- Mock dataGenerate up to 1000 rows of consistent fake data (name, email, Spanish IDs, IBAN, address…) as JSON, CSV or SQL. With a seed, always the same.
- PasswordsGenerate strong random passwords with crypto.getRandomValues, choose length and character types and see their entropy in bits. They are never stored.
- QR codeCreate QR codes for text, links or WiFi networks in your browser and download them as PNG or SVG. With accents, emojis and the error correction you choose.
- SlugTurn titles into clean URL slugs: no accents or symbols, with the separator you choose and without splitting words. One line, one slug.
Encoding
Encode, decode and inspect tokens and hashes.
- Base64Encode and decode Base64 as you type, with automatic detection and a URL-safe variant. Turn files into data URIs and Base64 back into files.
- URLEncode and decode URLs as you type (encodeURIComponent or encodeURI) and break any URL down: host, port, path, hash and query params.
- HTML entitiesTurn < > & " and ' into HTML entities, or everything non-ASCII, and decode &, é or 😀 as you type, right in your browser.
- JWTPaste a JWT to see its header, its payload and whether it is valid, expired or not yet valid, with dates in your local time. It never leaves your browser.
- Hash (MD5, SHA)Compute MD5, SHA-1, SHA-256, SHA-384 and SHA-512 of text or a file as you type, and compare against an expected hash to see if it matches.
Text & data
Format, compare and transform text and JSON.
- JSONFormat, validate and minify JSON as you type. Shows the exact line of any error and lets you explore the tree. Runs in your browser.
- Text diffCompare two texts and highlight added and removed lines and the words that changed. Unified or side-by-side view, ignoring spaces or case.
- RegexTest JavaScript regular expressions: highlight matches, list named groups, replace with $1 and get syntax errors explained in plain words.
- Case and linesConvert text into ten cases at once (UPPER, camelCase, snake_case, kebab-case…) and sort, clean up or number lines. With a character counter.
- JSON, YAML & CSVConvert between JSON, YAML and CSV in your browser: detects the format and separator, resolves YAML anchors and flattens nested objects for CSV.
- JSON diffCompare two JSON documents by structure and list added, removed and changed keys with their path, whatever the key order. Runs in your browser.
- MarkdownWrite Markdown and see it rendered instantly, with GitHub tables, task lists and code blocks. Copy the sanitised HTML. Runs in your browser.
- cURL to fetchPaste a cURL command and get the equivalent JavaScript fetch code, with method, headers, JSON or form body and notes on what fetch cannot do.
- Query stringTurn the parameters of a URL into JSON and JSON into a query string, with bracket notation, repeated keys and everything decoded so you can read it.
Identifiers
Official documents and codes: DNI, IBAN, plates, ISBN…
- DNI & NIECheck the letter of a Spanish DNI or NIE, work out a missing one and generate fictitious IDs for testing. Validates hundreds at once, one per line.
- CIF (Spanish company tax ID)Validate the CIF of a Spanish company, see its entity type and the right check character, and generate fictitious CIF numbers for testing.
- IBANValidate an IBAN from any country, break down a Spanish account (bank, branch and check digits), turn a CCC into an IBAN and generate test IBANs.
- License platesCheck current (1234 BCD) and old provincial (M-1234-AB) Spanish license plates, see their province or place in the series and generate test plates.
- Social Security numberCheck the control digits of a Spanish Social Security number (NSS), see its province and generate fictitious numbers for testing.
- Test cardsGenerate Visa, Mastercard and American Express numbers that pass Luhn for test environments, and validate any card number: brand and check digit.
- Spanish phone numbersCheck Spanish phone numbers, see whether they are mobile, landline or premium rate, and convert them to E.164 (+34612345678) and national format.
- SWIFT / BICCheck an 8 or 11 character SWIFT or BIC code and break it down: bank, country, location and branch, with its short and long forms.
- EAN & ISBNCheck the check digit of EAN-13 barcodes and ISBNs, work out a missing one and convert ISBN-10 to ISBN-13 and back, all in your browser.
- Postal codesType one or many Spanish postal codes to see their province, region and capital. Restores the leading 0 spreadsheets drop and shows each province’s range.
Converters
Dates, colors, number bases and units.
- Unix timestampLive Unix clock and conversion of timestamps in seconds or milliseconds to ISO 8601, UTC, local and relative time in any time zone, and back.
- ColorsConvert colors between HEX, RGB, HSL and OKLCH with every field editable and in sync, and check their WCAG contrast against white and black.
- Number basesConvert numbers between binary, octal, decimal, hexadecimal and any base from 2 to 36, with no size limit and optional digit grouping.
- UnitsConvert length, mass, temperature, volume, area, speed and data, and see the value in every unit at once, each one with its own copy button.
- CurrencyConvert between euros, dollars, pounds and 27 other currencies with ECB reference rates. The amount is computed in your browser and it works offline.
- px to remConvert pixels to rem and em and back, with your own base font size. Includes ready-to-copy CSS and a table of common sizes.
- chmodConvert Unix permissions from octal (755) to symbolic (rwxr-xr-x) and back, tick boxes and copy the chmod command ready for the terminal.
- File sizesType a size like 1.5 GB or 750 MiB and see it in SI and binary units, in bytes and in bits. Find out why a 1 TB drive shows 931 GB.
Calculators
VAT, withholding, percentages, rule of three and business days.
- Spanish VATAdd Spanish VAT to a net amount or take it out of a total, at 21, 10 or 4% or any rate you need. Cent rounding that always adds up.
- IRPF withholdingWork out a Spanish freelance invoice with VAT and IRPF withholding (15, 7 or 19%) from the base or from what you want to be paid, fully broken down.
- PercentagesWork out X% of a number, what percentage one amount is of another and the percentage change between two values, with discounts and markups.
- Rule of threeSolve direct and inverse rules of three: if A goes with B, what goes with C. Shows the formula with your values so you can see where the result comes from.
- Business daysCount calendar days, weekdays and business days between two dates, with Spain’s national holidays worked out for any year, Good Friday included.
Random
Wheels, draws and dice.
- Spin the wheelType your options, spin the wheel and let chance decide. Up to 100 options, a history of results and the option to remove the winner.
- Shuffle listPaste a list, one item per line, and put it in random order with a uniform algorithm. With a seed, the order can be repeated and checked.
- TeamsSplit a list of people into random teams, by number of teams or by people per team, with balanced sizes and an optional seed.
- Dice & coinRoll dice with tabletop notation (3d6, 2d20+1, d100) or flip a coin. See every die, the total and the history, with an optional seed.
Reference
Cheat sheets and quick explanations.
- HTTP status codesEvery HTTP status code from 100 to 511, with its official name, what it means, when to use it and the RFC that defines it. Search by number or word.
- CronTurn a cron expression into plain words and list its next run times in your time zone, with daylight saving changes handled like Unix cron.
- User-AgentPaste a User-Agent and see the browser, engine, operating system, device and CPU it reports, whether it looks like a bot, and your Client Hints.
- SemverCheck which versions satisfy an npm semver range (^, ~, x, hyphens and ||), with the range explained in words and the highest matching version.
- CIDR subnetsWork out the network, mask, broadcast, host range and usable addresses of an IPv4 subnet in CIDR or mask notation, and whether the IP is private or public.