Glossary
Twelve terms, with the specification attached.
Most glossaries define a word and stop. Each entry here states the standard, the byte count or the URI grammar that actually decides how the thing behaves — and links the document it came from, so the claim can be checked rather than believed. Terms we could only define in two sentences were left out rather than given a page.
- vCard.vcf fileWhat a vCard is, which version to use, and how a .vcf file behaves on iPhone, Android and Outlook. The format explained without the marketing.Read the entry
- NTAG213NTAG213 holds 144 bytes of user memory — enough for any short URL. The specification, what it costs you, and when a bigger chip is a waste.Read the entry
- NDEFNFC Data Exchange FormatNDEF is the record format every phone expects on an NFC tag. What a URI record looks like, how the prefix byte saves space, and why it matters.Read the entry
- QR error correctionL, M, Q and H decide how much of a QR code can be damaged and still scan — and how big the code gets. Which level to pick, and when.Read the entry
- Dynamic QR codeA dynamic QR code encodes a redirect, not a destination. What that buys you, what it costs, and the failure mode nobody mentions when selling them.Read the entry
- UTM parametersutm_source, utm_medium, utm_campaign, utm_term and utm_content — what each one is for, which are required, and the convention that keeps reports readable.Read the entry
- wa.me linkWhatsApp click to chatThe exact format of a WhatsApp click-to-chat link, why the number has no plus sign or spaces, and how to pre-fill the first message.Read the entry
- tel: URIThe tel: URI scheme is defined by RFC 3966. The format, why the number should be global, and the punctuation that breaks a call button.Read the entry
- E.164E.164 is the ITU standard for international phone numbers: a plus, a country code and up to fifteen digits. Why every stored number should use it.Read the entry
- Open Graph imageog:imageThe Open Graph image is the picture that appears when your link is pasted into a chat. Dimensions, aspect ratio and the tags that go with it.Read the entry
- MeCardMeCard packs contact details into far fewer characters than vCard, which is why QR generators use it. The grammar, and where it falls short.Read the entry
- Deep linkUniversal Link, App LinkCustom schemes, Universal Links and App Links do the same job three ways. Which one a link on your page should use, and why it sometimes fails.Read the entry
Working guides rather than definitions live in resources, and the free tools put several of these specifications to work without a signup.