How about an alert if I leave home without my card, or leave it in a restaurant/bar or if it’s in my bag/wallet and I walk off without it (or it walks off without me)?
Probably needs some proximity technology and pairing with my phone but could help prevent lost cards and report stolen ones faster.
I’m not sure how this could be enabled from a technical standpoint?
Previously discussed in this linked thread but the complexity and cost this feature would add to the card makes it unfeasible. 
I can only really think something like a Tile Slim would be an easy way to implement this yourself? Although it’s a whole wallet finder and not just for the card itself.
This is exactly what I was thinking. Even the Tile Slim isn’t thin enough to be embedded in a card and only lasts 1-2 years.
What about the RFID used for contactless payments?
Isn’t the range of this less than 10cm? You’d also have to have your phone’s NFC on constantly registering the card being there which, amongst other things, is probably going to use a lot of battery.
Available for Revolut cards
Monzo uses location data to detect fraud.
If your phone shows that you’re in the UK all the time then they have a transaction the same day from China it’s likely to be fraudulent.
The location thing on Revolut isn’t too great though. I turned it off on mine. Too many ATMs I tried had their location set as a location not where it is (maybe the head office, nearest branch, data centre, I don’t know) so transactions just get declined.
Happens at POS too. Whenever I use Gail’s in Hampstead the location that comes through is in Hendon, where the office is.
That’s a different feature which is designed to prevent fraud, it wouldn’t help you if you’d forgotten / lost your card because that feature relies on you making transactions, in order to locate the card.
Active RFID tags have significantly bigger range, up to 12 meteres (last time I researched this topic). They shouldn’t be too big either, but range(antenna) and battery life are strictly linked to size of the tag. Wholesale prices are a fraction of a dollar for 1 tag, but production costs/assembly costs would need to included too…
I don’t think that active rfid tags will be strong enough for bigger houses and false positive (phone in bedroom, wallet downstairs) situations can happen.
That being said, NFC in phones is not the same as UHF RFID, so I’m not sure how active or passive rfid tag could be read by phone. Can it be solved without adding 3rd device to be a link between phone and card?
Maybe we can have some sort of tracker (any technology) with nice battery in a form of keyring attached to card? Can cards have holes? Contactless wouldn’t be affected and you put only half of the card in POS terminals - those can use card with tracker attached. Only ATMs would require user to detach tracker dongle, but it would still need to be nice/quick to attach/detach tracker. Card would still fit well in wallets in most cases if tracker dongle has good shape + not very big.
Been using mine for 14 months in 5 different countries and not had a location problem, yet.
Used mine in 12. Germany and Brazil being the ones where this happened with ATMs.
POS issues can happen anywhere as per the Gail’s example.
How about using nfc/contactless chip already in phone and card and then storing card with phone. Most phone cases have a slot for one or more cards.
Then after a transaction notification the app could use nfc to check that the card had been returned to the phone case and alert after a min or so if not.
I know it would not suit 100% of users but uses tech thats already in place so would be a software only solution.
You’d potentially be looking at about 1000 people from 400,000. It wouldn’t be worth the development time (yet). #RoadToOneBillionUsers
I like this idea but having read the thread it would seem unlikely to be able to implement this.
A work around you may like to use is to set a permanent reminder on your phone based on your location.
For example I have in the past used it to set a reminder when I leave a location (one time set up per location, home, work, mate’s house etc) the reminder lists: phone, wallet, keys or whatever other items you may have left.
Obviously it does not know when you have left your card behind but at least you are reminded when leaving regularly frequented locations to double check you have all your stuff with you, including your Monzo card 