A vCard QR code on a business card can carry the whole contact or a link to a page with the details. How much room each takes on the card, what to enter and when the link stops working.
A QR code with a logo works thanks to error correction, but its "30%" counts codewords, not area. How much logo our code survived, what not to cover and how to check it before printing.
Google gives you the Google review link and a ready QR code in your Business Profile. Where to click, how large to print the code and what Google's policies forbid when you ask customers for a review.
Minimum QR code size depends on what the code contains, not on centimetres. Seven causes of a QR code not scanning in the order to check them, and a formula for the smallest print size for your content.
How to make a QR code in a few minutes, which type to pick, what exactly is stored inside the code and when a static code is enough and when you need a code on a short link.
How to shorten a link in a minute, why a link shortener should redirect with 302 rather than 301, where to add UTM parameters and what the goo.gl shutdown teaches.
What each of the nine UTM parameters means, which rules GA4 uses to assign a channel, why letter case splits your report and how UTM tags work with a short link and a QR code.
Set up link tracking in DVN Links with a short link and QR code, and learn what each click records, what the statistics show and what happens to a free-plan link after 30 days.