Tạo Mã QR Website Miễn Phí

A static QR code encodes the destination URL directly into the code's data modules. Once printed, it cannot be changed. If the URL breaks or you want to point to a different page, you need to generate and print a new code.

A dynamic QR code encodes a short redirect URL instead. When someone scans it, the redirect service forwards them to your actual destination. You can change that destination at any time without reprinting the code. Dynamic codes are smaller and simpler because the redirect URL is short, which means fewer data modules and easier scanning.

The trade-off is that dynamic codes depend on a redirect service staying online. If that service goes down or the company behind it shuts down, every code you printed stops working. For permanent installations like building signage or product packaging, static codes pointing to URLs you control are often the safer choice. For marketing campaigns with a defined lifespan, dynamic codes give you flexibility to adjust targeting without reprinting materials.

UTM parameters let you track exactly which QR code placement drove traffic to your website. They are tags appended to your URL that analytics tools like Google Analytics 4 recognize. The five standard parameters are utm_source (where the traffic comes from, like 'flyer' or 'poster'), utm_medium (the marketing channel, like 'qr_code'), utm_campaign (your campaign name), utm_term (optional keyword targeting), and utm_content (to distinguish between different placements within the same campaign).

A tracked URL looks like: yoursite.com/landing?utm_source=store_window&utm_medium=qr_code&utm_campaign=summer_sale. In GA4, this traffic shows up under Acquisition with the source, medium, and campaign clearly labeled. You can then compare conversion rates between different QR code placements.

One important note: UTM parameters make URLs longer, which makes the QR code more complex. If your base URL plus parameters exceeds 150 characters, consider using a URL shortener first, then adding UTM parameters to the shortened link.

URL shorteners like Bitly, TinyURL, or your own domain-based shortener reduce long URLs to something compact, which keeps QR codes simple and easy to scan. But stacking redirects creates problems. If your short URL redirects to a tracking URL, which redirects to your actual page, that is three HTTP requests before the user sees content. Each redirect adds 100-300ms of latency, and any link in the chain failing breaks the entire flow.

Keep redirect chains to a maximum of one hop. The most reliable setup is: QR code contains your short URL, short URL redirects once to your final destination (with UTM parameters on the final URL). Test the full scan-to-page experience on a real phone before printing.

Also consider link rot. Short URLs from free services can expire, get reclaimed, or the service itself can shut down. For QR codes with a lifespan longer than a year, use a shortener you control (a custom domain redirect) or encode the full URL directly.

QR codes are increasingly used in phishing attacks because users cannot see the URL before scanning. As a QR code creator, you can build trust by following a few practices. Always use HTTPS URLs. Modern browsers show security warnings for HTTP links, which makes your code look suspicious even if the content is legitimate.

Display the destination URL in small text near the QR code so users know where they are going before they scan. Use your own domain rather than a generic shortener, since custom domains look more trustworthy than random short links.

From the scanning side, both iOS and Android now show a URL preview before opening the link, so users can check the domain. But this only works if the URL is readable. A URL like yourbrand.com/summer-menu is clearly legitimate, while x7q.link/a3f is not. If you are placing QR codes in public spaces, add your brand name or logo to the code and include a brief note about where the code leads. This reduces the chance that someone replaces your code with a malicious one, a tactic known as QR code overlay attacks.