QR code guides
Straight answers about expiry, safety and printing, from the people who run the redirects.
- Do QR codes expire?A static QR code never expires: the destination is stored in the pattern itself. A dynamic QR code can stop working at any time, because it depends on the company hosting its redirect, and many generators disable codes when a free trial or subscription ends.
- Static vs dynamic QR codes: which should you use?Use a static QR code when the content will never change (Wi-Fi, a contact card, a permanent page on your own site). Use a dynamic QR code when you need to change the destination after printing, count scans, or detect tampering, but only from a provider that will not deactivate it.
- What is quishing? QR code phishing explainedQuishing is phishing delivered through a QR code. Scammers place fake codes, often stickers over genuine ones on parking meters, tables and posters, or send them in emails, to lead people to cloned payment or login pages.
- How to tell if a QR code is safe before you scanCheck whether the code is a sticker placed over something else, read the web address your camera shows before opening it, avoid short links that hide the destination, and never enter payment or login details on a page reached from an unexpected code. When in doubt, run it through a QR safety checker.
- How businesses can protect QR codes from tamperingPlace codes behind protective covers where possible, print your official domain and a human-readable code next to them, use a verification step customers can recognise, inspect public codes regularly, and monitor scans so you are alerted when a code suddenly stops being used.
- What size should a QR code be? Print size guideAs a rule of thumb a QR code can be scanned from about ten times its width, so a 3 cm code works at about 30 cm. Keep each module (the small square) at least 0.33 mm, and ideally 0.5 mm or more, and always leave a quiet zone of four modules around the code.
- QR code print checklist: 12 checks before you printBefore printing, check contrast (dark code on light background), a four-module quiet zone, adequate size for the scan distance, vector artwork, a matte finish, a tested destination, and your QR provider's cancellation terms. Then scan a physical proof on two different phones.
- Why did my QR code stop working? 8 causes and fixesThe most common causes are an expired dynamic-code trial or subscription, a broken destination link, damage or glare on the print, poor contrast, a missing quiet zone, printing too small, or a sticker placed over the code.
- QR code error correction levels explained (L, M, Q, H)Error correction lets a scanner rebuild a damaged or covered part of a code: level L recovers about 7%, M 15%, Q 25% and H 30%. Higher levels make the code denser, so use M by default and H when you add a logo or print for rough environments.
- QR code tracking and privacy: what you can measure responsiblyA dynamic QR code can count scans, unique visitors per day, approximate country and city, and device type. None of that requires storing IP addresses or personal data. Kizmo keeps only a salted, day-scoped hash for unique counts and never stores raw IPs.
- Which QR code generators keep your codes working after you stop paying?It depends on the provider. QR Code Generator, QR TIGER and Uniqode deactivate dynamic codes when a trial ends or a plan lapses, according to their own help pages. Flowcode, Bitly and Kizmo keep existing codes working after you downgrade or cancel. Static QR codes never expire at any of them.