Launching 3D Secure!

Had one on Amazon the other day and trainline as well so I think most companies. I guess yours are low risk so have been auto approved without you notficing

Amazon don’t use 3D secure and never have to the best of my knowledge.

Correct, they don’t even process CVV code

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Does the algorithm learn per say - i.e each person has a 3D Secure profile of their habits etc.

It’s quite complex. Details here.

Any ideas why they dont but other companies do?

Yes, they knew it introduced too much friction and would lead to many abandonded purchases. I assume they opted to take more risk and use their own fraud preventiion methods. E.g. if you request shipping to a new address they require you to re-enter your card details. They will have other non-public risk assesment algorithms.


I’m curious to know why your fiver example the 3D Secure flagged it. When it should have flagged it as a low risk purchase? As on the whole only 2% of transactions are deemed high risk. I would assume that is based off merchant data from the website. What would be interesting would be how many times you get flagged if you use a VPN in contrast to not using one. As I assume there are lots of metrics that are taken into account such as value of transaction, location and search history

I assume, but do not know, that the fiver purchase required verification because it was the first purchase with the card at that merchant.

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That’s exactly what I was thinking

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So if a business opts to use 3D secure is the bank liable?

And the opposite if they dont?

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I imagine there may also been a random flag as well.

In the sense of flag on average 1 in 100 transaction per person just because or something much higher

I don’t know the subject well enough, there are others here more informed but I assume the liability for fraud is shifted from the merchant if they use it.

I found quite a good article on the subject that shows when there is liability shift


I recently used 3D secure for the first time in the UK and it actually made sense. Before in the US I would get the familiar frame with my bank’s logo, but that was it. The transaction would go through.

With Monzo it has me verify in app or by SMS.

Anyone know what is up with the difference?

CC: @GalaxyMergirl

In terms of approval, no difference

Some websites and apps can fail the transaction when you switch apps (to the Monzo app to approve in this case), which is rubbish design on their part, but can be avoided by using SMS instead and reading that from your notifications

I also had an issue with one merchant in the past when approving in app failed twice so I took to using SMS for a few weeks

What I am saying is with my US bank there is no verification whatsoever, so I don’t really understand the point of 3-D secure. However with Monzo it seems to actually perform some sort of verification which makes 3-D secure make a lot more sense

Did you have to enter some characters into that frame?

If so, that might have been like SecureCode (IIRC) over here before, which seems to have (thankfully) disappeared now

If they were both using 3D Secure, then I believe it comes down to risk appetite

Monzo auto-approve some of my transactions with a pattern I cannot totally discern - that is one area where there can never be that much transparency - but generally allows through transactons with merchants I have been to before and transactions from major retailers

@Js38wju3jda In general, US banks didn’t really support 3D Secure. Most likely they ‘supported’ it, but approved everything with no intervention, hence you not seeing anything.


Thanks @Liam_W

No I did not have to do anything whatsoever.