A MECARD QR code saves a contact to a phone, like a vCard but in a much more compact format. It was designed for Japanese feature phones, and that heritage is exactly why it is smaller — and why support is less universal.
The payload is a compact record: MECARD:N:Last,First;TEL:…;EMAIL:…;; Fields are separated by semicolons and the whole thing ends with two, and there is no per-line structure — which is where the size saving comes from compared with a vCard, where every property is its own line with its own name.
Smaller matters more than it sounds. A contact code is often printed on a business card, which is the smallest surface anyone prints a QR code on. Fewer characters means fewer modules, larger squares at the same physical size, and a code that still scans after being in a wallet.
The trade is support. Contact Card (vCard 3.0) is the format every phone, every contacts app and every CRM understands. MECARD is understood by most modern scanners but not all, and by fewer desktop tools. If the card matters more than the size, vCard is the safer choice — and it is free here too.
The case MECARD is genuinely better at: a small code that still scans reliably from a card in poor light.
Contact details that save rather than just display, printed small enough not to dominate the badge.
Anywhere the printable area is the constraint and the contact details are short.
Support is good but not universal. Some scanners show the raw MECARD: text instead of offering to save a contact. Contact Card (vCard 3.0) does not have that problem.
It carries less than a vCard. No photo, no structured multi-line address, fewer field types. That is the source of the size advantage rather than an oversight.
Reserved characters are escaped, and a hand-built MECARD usually gets this wrong. A colon or semicolon inside a value truncates the record silently. Generated here it is handled; typed by hand it is the most common defect.
Everything in it is public. A printed contact code can be decoded and harvested in bulk, so use work details rather than home ones.
The address is a single free-text field. Phones display it, but they cannot split out a city or postcode that was never sent separately.