Allow only one QR code

Once checked in, no other user with a photocopy of the QR code should be allowed.

Hi hatcc,

Thanks for reaching out to Jotform Support. To my understanding, you wish to send a QR code to your users which will be scanned at the entry. When a QR code is scanned once, it should not be possible to scan it the second time.

To achieve this, you would need two forms. The first one that will be submitted by your users and will generate the code, and the second one for verification. My colleagues will explain how to configure QR code in other threads, we'll focus on checking it.

Here's how to add QR reader to your form:

1. Open your Form in the Form Builder and click Add Element on the left.
2. Choose the Widgets tab.
3. Search for QR.
4. Drag QR Code Reader to your form.

To make this work, we'll also need a short text field. Here's how to add it:

1. From the Form Elements panel, choose Basic tab.
2. Add Short Text field to your form.

Now, we need to populate this with a value. We can do this with conditions:

1. From the top orange bar, click on Settings.
2. Choose Conditions from the left side.
3. Click on Update/Calculate Field.

Configure the condition like this:

Finally, we need to check if the code has already been submitted. This can be done from the form settings:

1. From the top orange bar, choose Settings.
2. Click on Show more options button.
3. Scroll down and locate Unique Field option.
4. Choose previously added short text field here.

Now, if one code is already used, a message will be shown after the form has been submitted.

Give it a try and let us know how it goes.