Does K-9 register for mailto:-URLs?


I’m trying to track down this problem:

Xiaomi Mobile with Android 12, and trying to use NFC-Tags to automate certain things when putting the phone near the tag, in the usual way.

Although I am using K-9 as a mail client, and have set K-9 in the system settings as the preferred mail app, the android nfc service offers the gmail app only to send mail, if a mailto-URL is set as one of the commands on an NFC tag.

Now I am trying to figure out whether Android’s NFC-service ignores the preferred app setting, or whether responding to mailto:-URLs requires a special setting, which is not set by K-9.


K-9 Mail does register for mailto: URIs once an account has been set up. You should be able to test this by tapping a mailto: URI in a browser.

Yes, I should.

But nothing happens then.

But it’s not a general problem of the phone. E.g. a… URL is properly resolved to the X app. It seems to be a particular problem of K-9.

There is definitely a problem with K-9 and the registration of URLs. Although I can – sometimes – open K-9 from the browser when opening an url with a mailto: URL, K-9 does not get listed by Android’s RFID reader, while other apps like gmail, BlueMail, Aqua Mail (even if not configured at all and never used) are:

The Tag was loaded with three entries, the Label “NFC RFID Test”, a mailto url and a phone number.

As you can see, the mobile presents the label, three apps to respond to the mailto url and to apps to the phone number. But not K-9.

So all the other three apps are doing something correctly, while K-9 does it wrong, is not found by the RFID-function of Android.