Everything in the catalog

Converts JSON to YAML with a live two-pane view.

Decodes a JSON Web Token and shows its header and payload claims.

Press any key to see its JavaScript key, code, keyCode, location and modifier values.

Processes column-style lists by transposing, sorting, reversing, adding prefixes or suffixes and changing case.

Generates random MAC addresses for a given quantity, prefix and letter case.

Looks up the vendor behind a MAC address from its OUI prefix.

Evaluates a typed math expression and supports functions such as sqrt, sin, cos and abs.

Converts a MIME type to its file extensions and a file extension to its MIME type.

Shortens a word into a numeronym such as i18n or a11y by counting the letters in the middle.

Generates the Open Graph and social-card HTML meta tags for a web page from a few fields.

Generates and checks time-based one-time passwords for two-factor authentication from a secret.

Extracts the original URL from a Microsoft Outlook Safe Links wrapper link.

Checks the digital signatures embedded in a signed PDF file.

Works out a percentage of a value, a value as a percentage of another, or percent change.

Parses and validates a phone number and reports country code, type and international format.

Makes a downloadable QR code from a link or any text, with choices for colours and error correction.

Picks a random port number outside the well-known 0-1023 range for local development.

A reference of regular expression syntax for JavaScript with examples of each token.

Tests a JavaScript regular expression against sample text and shows matches and capture groups.

Turns Roman numerals such as MCMXCIV into ordinary integers and writes integers as numerals.

Generates a new random RSA public and private key pair in PEM format.

Turns text into a slug that is safe for URLs, filenames and ids by removing accents and special characters.

Formats SQL queries with indentation, with options for several SQL dialects.

Masks the middle of a secret, token or IBAN so you can share it while keeping it recognisable.