Feasibly Asked Questions

Just about everywhere we look on the Internet there is a frequently asked question section. We wanted one as well, but no one has asked us any questions yet. Because of this we have had to create a Feasibly Asked Questions section of questions that may well be asked but have not been (yet). If you have any more questions then please ask them though our User Voice page or contact us directly.

What is a QR / QR Code

Although we keep referring to a "QR", in fact we are referring to a "QR Code", or a "Quick Response Code" to use its full name. The QR Code was developed by Denso Wave who have a patent but have chosen not to exercise it. This has resulted in the QR Code being free to produce and use and we thank Denso Wave for that. The term "QR Code" is a registered trademark of Denso Wave Incorporated.

What size should I print the QRs?

For best results you should make your QR 32mm (approximately 1.26 inches) but according to a report, most phones will read a QR okay sized at 26mm (approximately 1 inch). You should also leave the white border around the QR. QRs can be printed smaller, but the smaller you make them the fewer devices will be able to recognise and decode them, regardless of the print quality used. More guidance is available on the Denso Wave web site.

What are the dots per inch?

Let's say 300 DPI. The real answers is "it depends", and/or "it is not relevant", but if you really really insist on a value then 300 DPI is good.

What software reads the QRs?

There are lots of clients to read QRs. The easiest way to find them is to go to getreader.com on your mobile phone and you will see a selection that work on your device.

Do I need to test the code?

We know you are not going to ask that, and you know you should, but many people do not. The world is full of QRs that have not been tested and do not work. Do not look like an idiot and test your QR works before it is too late.

What is your service level agreement?

In short there is no guarantee or service level agreement. We developed the service for us to use and allow others to use it for no financial gain at their own risk. If you are using a SmallQR or our Extra Small QR you are relying on our services being unaffected. If you are using Bit.ly, Goo.gl, or TinyURL then you are relying on their service being unaffected. Although it is unlikely a failure will happen it is still possible. If you can not afford to have a link become unavailable in a worst case scenario then we recommend setting up your own service or paying us to organise it for you.

What are Extra Small QRs?

This service tries to make QRs as small as possible. The most reliable way to do this is to reduce the data it contains, and that requires a very short URL. We have purchased a 6 character domain name (3 characters, a period, and 2 characters) that will allow us to create these. As this is a limited resource, we are going to be limiting their use after beta by only allowing people who donate to the service to use them. It should be noted that the URL we use is under the jurisdiction of the Isle of Man who by contract can take back the domain at any time, although this is considered unlikely to happen.

What error correction setting do you use?

The error correction level used depends on the length of the URL used, and that in turn depends on the URL shortening service used. If TinyURL are used, an ECC level of "M" is normally used allowing the QR still to scan if up to 15% of it is damaged. If Goo.gl or Bit.ly are used an ECC level of "Q" is used allowing the QR still to scan if up to 25% of it is damaged. Our shortening services used an ECC level of "L" allowing one to scan if up to 7% of it is damaged. We strongly recommend making the QR pixels bigger instead of increasing the ECC level when mobile phones cameras are being used so this is not a user setting.

Should I use uppercase URLs?

If creating an unshortened QR then using only uppercase letters and numbers are on average 30% more efficient than other characters so you QR may well be smaller. However it makes no difference when using any of the URL shorteners.

Can I have another file format?

We generate the QRs as PNG bitmap images and as SVG vector images. These should be suitable for a vast majority of uses. If you really need it in another format then there are many online image conversion services available to help. If you think we need to implement another format then please let us know.

Can I have the QR as a JPG?

No. Seriously you do not want a QR code as a JPEG. This JPG compression is for encoding photos, and images with rigid lines like QRs do not compress well.

How many Small QRs are there

Currently there are approaching 4,000 QRs issued using our shorteners (updated within the last 24 hours). We can cope with a total of 72,057,594,037,927,936 standard QRs with the current setup, but we can add over 1 quintillion if needed. Actually we can add more but our calculator gave up at a quintillion. This will require a hardware upgrade. ;-)

Can you use 301 Redirection?

No. Under normal circumstances we use 302 redirection that has the same affect to the user. We do this for technical reasons to make SmallQR less likely to be abused.

How do I get rid of the security warnings?

We check all links against a number of block lists and warn the user if it is found on one. We do this to protect the user and to prevent SmallQR from being used by spammers. The user scanning the QR always has the option of ignoring the warning, but the warning can not be turned off. We also warn the user if a SmallQR URL is linked to from another web site for the same reasons.

Will you show advertisements?

We might take advertisements on the main web site in the future. It is not our intention to ever send out advertisements when people scan the QRs.

What happens if you close down?

Although a self-funded pet project, the base of SmallQR is self-contained and not dependent on other APIs, and the running cost is low, so we should be able to keep running for the next few years without interruption. We are also a member of 301 Works so other members will take over managing the redirection service should we not be able to continue for any reason.

Why all the small quotes on the home page?

Because we could not find any interesting quotes about QRs. Reflecting on it I don't think we found any interesting quotes about small things either. Sorry about that.