Validity of a QR Code


I have a QR Code that leads to a link. This link, I suppose, will air until 2015. Of course, when the link does not exist, this QR Code will not get you anywhere.

My question is: Does this code have validity? Or, for example, someone in Transylvania can generate a QR Code similar to mine.

I ask this, therefore, I intend to store them.

asked by anonymous 27.08.2014 / 19:12

3 answers


I have a QR Code that leads to a link. This link, I suppose, will air until 2015. Of course, when the link does not exist, this QR Code will not go anywhere.

  • That's basically it. Probably it goes to a 404 or to a server not found.

My question is: Is this code valid?

  • The code will be read at any time since the information contained in it is not dependent on anything external.

Does anyone in Transylvania have a QR Code similar to mine?

  • Absolutely. The QR Code content is just a stream of bytes, which outputs a string. Just someone use the same string, and here's the QR with identical value. And the coolest, you do not even need to be in Transylvania for that.

    Even if the person uses the same compression and encoding criteria, the image will be identical.

I ask this, therefore, I want to store them.

  • Do you want to store the image or link? (remembering that not only links that can be stored in a QR Code, any string can be stored, for the most diverse purposes)

    The most common purposes are links, wi-fi data and electronic business cards. But there are still internal use codes, such as packaging IDs, or anything else you might imagine replacing conventional bar codes.

    If you store the images, you will probably be storing more information than needed, unless you had a very special use for the encoding features used (which is unlikely).


Suggestion for who to create their own codes:

Do not use short third-party links. Create your short links system, and store your data in your own DB, preferably under an internet domain that you can keep for as long as you like.

See the main reasons:

  • You prevent the link from "expiring", or cease to exist if the short link provider has issues or deadlines.

  • You can correct a wrong link. I've already seen a case where a large-scale magazine had to compromise with a shorter of famous links, thanks to a link that was published wrongly on the cover of the magazine. If you manage your own links, just replace the wrong one with the correct one in the DB, and the problem is solved.

  • You can point a QR of an old link to a friendly message telling you that the link has expired, rather than simply breaking the access, creating a better user experience, and maybe leading you to something else interesting , not missing the visit.

Obs: I say short links, because the less information, the better the readability of a QR Code. Remember that when it is the case, you can use almost 7KB in a single code, but in practice, only with a professional scanner you will be sure to read a QR with so much information.

Incidentally, I humbly dare say that the people who normalized the receipt of NFC-e - which started to be used in some states instead of the tax coupon - made a big mess by putting a lot of unnecessary information in the QR Code, making it "inescapable" by many devices. And look at one of the premises was that of the merchant to save on the printer used. In practice, the printer has to be good, and so does the reader. If they had done it in a more sensible way, even a dot matrix printer would solve it.

27.08.2014 / 19:58

Most solutions of this type

27.08.2014 / 19:40

I think it's not valid, because QR Code is a standard, as is the bar code. When a QR Code reader is used to read your code, it will simply translate the code into the link you used to create it.

I even did the test, I found a magazine about 2 years ago with a code and it read normally, only the link that was in it no longer existed.

27.08.2014 / 19:49