Barcode Generator - Build and check EAN-13, UPC-A and EAN-8 numbers with the GS1 check digit worked out term by term. The bars are drawn here as an inline SVG rather than fetched from an outside service, and the prefix is looked up so you know which GS1 office issued it.
QR Code Generator - Seven kinds of payload, one symbol: a web address, a Wi-Fi network, a contact card, a text message, a phone number, an email address or plain text. The code is encoded and drawn in your browser as a vector image, so a network password on a table card never reaches an outside server.
UTM Link Generator - Campaign parameters appended to an address you were going to share anyway, with two checks a hand-built link never gets: which channel group the pair lands in, and whether an anchor will throw the tracking away.
SEO Meta Tag Generator - How long is a title? Not a number of characters, since a W is over three times the width of an i. Both fields are measured in characters, bytes and width, and everything you type is escaped.
UUID Generator - Six versions, five output formats and up to 100 at a time, plus a second mode that takes an identifier somebody else made and reads back its version, its variant and the moment hidden inside it.
CSS Gradient Generator - Which point along the blend breaks your text? Two to eight stops in linear, radial or conic form, with contrast measured at every whole percent and a solid fallback written in.