QR code glossary · Dynamic codes and tracking
Redirect
Also called: HTTP redirect, URL redirect
Definition
A redirect is an HTTP response with a 3xx status code and a Location header that tells the browser to load a different address; it is how a dynamic QR code’s short link forwards each scan to the code’s current destination.
How it works
When a phone opens a short link, the server answers with a status code and the address to go to next. The browser follows it immediately, usually in a fraction of a second. HTTP defines several redirect codes; RFC 9110 sets out what each means:
| Code | Meaning | Permanent? | Request method |
|---|---|---|---|
| 301 | Moved Permanently | Yes | May change from POST to GET |
| 302 | Found | No | May change from POST to GET |
| 303 | See Other | No | Becomes GET |
| 307 | Temporary Redirect | No | Kept |
| 308 | Permanent Redirect | Yes | Kept |
A scan always makes a plain GET request, so for QR codes the method rules make no difference, and 302 and 307 behave the same. The difference that matters is permanence. Under the HTTP standard, 301 and 308 responses can be cached by default, so a browser may remember them and skip the redirect service next time. Temporary redirects are not cached unless the server says so.
Why it matters
A dynamic QR code should use a temporary redirect, 302 or 307. Then every scan reaches the service, so an edited destination takes effect for everyone and every scan can be counted. With a cached 301, a phone that scanned before may go straight to the old destination, and its repeat scans go uncounted. A service can also send Cache-Control: no-store as an extra guard.
Permanent redirects also signal to Google that the target address should replace the original in search results; temporary ones keep the original. That matters for moving web pages, rarely for QR short links. One practical tip: point a code at the final address of the page. Every extra hop, such as http to https or a missing www, adds a round trip, and some redirects drop query strings like UTM tags.
Example
GET /r/A7K2Q9 HTTP/1.1
Host: example.com
HTTP/1.1 302 Found
Location: https://example.com/spring-menuIn CirculateQR
CirculateQR’s short links answer scans with temporary redirects (302 Found for an ordinary link), so an edited destination applies from the very next scan.
Related terms
- Short URLA short URL is a brief web address, such as example.com/r/A7K2Q9, that a server forwards to a longer destination; dynamic QR codes encode one so the printed pattern stays small and the destination can change without reprinting.
- Dynamic QR codeA dynamic QR code is a QR code that encodes a short link to a redirect service instead of the final content, so the destination can be changed after printing and each scan can be counted, for as long as the service keeps the link active.
- Scan analyticsScan analytics are the records a dynamic QR code’s redirect service keeps each time the code is scanned, typically the time, an approximate location from the IP address, the device, operating system, browser and language, summarized into counts and charts.
- UTM parametersUTM parameters are standard tags, such as utm_source, utm_medium and utm_campaign, added to the query string of a link so web analytics tools such as Google Analytics can tell which campaign, source and placement sent each visitor.
- Deep linkA deep link is a link that opens a specific screen or item inside a mobile app, such as a product page, rather than the app’s home screen or a website; in a QR code it is usually an ordinary https address that the phone hands to the installed app.
Learn more
- Change where a QR code goes after printing: Editing the destination behind a printed code.
- Dynamic vs static QR codes: What the redirect adds, and what it costs.
Sources
Last updated . Written by the CirculateQR team; technical facts follow the sources listed above. Example codes and sizes are computed with the open-source qrcode encoder that CirculateQR uses. Spotted something wrong? Email support@circulateqr.com. QR Code is a registered trademark of DENSO WAVE INCORPORATED.
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