What is a Dynamic QR Code and How Does It Work?
The technology behind the QR code you can edit without reprinting
A dynamic QR code encodes a short URL managed by a server instead of the final destination. When someone scans the code, the server checks the current destination and redirects in milliseconds. This allows you to change where the QR points at any time, without modifying or reprinting the physical code.
How does a dynamic QR work technically?
The QR encodes a short URL like codigo-qr.es/r/abc12345. When scanned, the server reads that URL, looks up the configured destination and redirects. The physical code never changes.
The architecture is simple but elegant. The QR code printed on paper encodes a short URL — for example `codigo-qr.es/r/abc12345`. This URL is fixed and never changes.
When the phone reads the code, it visits that URL. The codigo-qr.es server receives the request, queries the database for the destination configured for that code, and returns an HTTP 302 redirect to the final URL. All of this happens in 50–200 milliseconds, imperceptible to the user.
You control that destination from the dashboard: you can change it at any time. The next scan of the same physical code will go to the new destination.
As a side effect, the server records the scan anonymously: IP address (hashed with a daily salt, not reversible), country and city by approximate geolocation, browser User-Agent (device, operating system) and timestamp. Never personally identifiable data.
What's the difference between a dynamic QR and a UTM QR?
A dynamic QR uses server-side redirect: the destination is editable. A UTM QR appends parameters to the final URL: the destination is fixed but appears in the client's Google Analytics.
There are two ways to 'track' a QR and they're very different:
Dynamic QR (redirect mode at codigo-qr.es): The physical code points to our server, which redirects to the destination. Analytics lives in the codigo-qr.es dashboard. The destination is editable. No Google Analytics needed.
QR with UTM parameters (UTM mode at codigo-qr.es): The code encodes your final URL directly with parameters like `?utm_source=poster&utm_medium=qr&utm_campaign=summer`. No redirect: the code is static. Analytics appears in your Google Analytics. The destination is NOT editable (if you need to change it, you have to reprint).
When to use each? If you already have Google Analytics set up and want scans to appear in your traffic reports, use UTM. If you want flexibility to change the destination and your own analytics without depending on GA, use dynamic.
Does a dynamic QR work with any QR reader?
Yes. The reader can't tell the difference between static and dynamic: it reads the short URL, opens the browser and the redirect happens transparently. Compatible with iOS, Android and industrial readers.
From the reader's perspective, a dynamic QR is identical to a static one: it contains a URL that the reader opens in the browser. The reader doesn't know a redirect is going to happen.
Compatibility:
• iPhone (iOS 11+): native camera, no additional app
• Android (9+): native camera on most models
• Industrial readers (Zebra, Honeywell, etc.): they read the URL and process it according to their configuration
• Specific applications (QR Scanner, Scanbot, etc.): all compatible
The only limitation: the phone needs an internet connection for the redirect server to look up the destination. Without coverage, the short URL loads but can't redirect.
When should you NOT use a dynamic QR?
When the data is permanent and you don't need analytics, a static QR is simpler and doesn't depend on any server. Ideal for permanent contacts, corporate WiFi or websites that don't change.
A dynamic QR isn't always the best option. Don't use it when:
The data will never change. Your main company URL, your LinkedIn profile, your office WiFi credentials that have been the same for 5 years. Static is simpler and dependency-free.
You need total privacy. A dynamic QR goes through a server. Even though data is anonymous and encrypted, if the use case requires absolutely no intermediary to see the traffic, static is the only option.
You work in offline environments. In warehouses, industrial buildings or rural areas without coverage, a dynamic QR can't complete the redirect. For data that must be readable offline (serial number, part identifier), use a static QR with plain text.
You only need a one-off solution. If you're generating a QR for a PowerPoint presentation you'll use this week and never again, static is sufficient and free without registration.
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Preguntas frecuentes
- Does a dynamic QR expire?
- The physical code never expires. The redirect service works while the codigo-qr.es account is active. With the Free plan you have up to 3 active dynamic QRs with no expiry date.
- Can you see who scanned my dynamic QR?
- No. Analytics are anonymous: they record country, city by geolocation, device type and time, but don't identify or track the individual user. The IP address is hashed daily with a salt and is not reversible.
- Is a dynamic QR harder to scan than a static one?
- No. From the reader's perspective they're identical. A dynamic QR actually carries less data (a short URL instead of the full URL), which technically makes it even easier to scan: fewer modules, greater tolerance to damage.
- How many scans can a dynamic QR handle?
- Unlimited. The codigo-qr.es infrastructure has no scan limit per code. A dynamic QR can receive millions of scans.
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