Circuitry inside the card

I’ve found by accident looking through the card, there’s some interesting circuitry towards the top of the card I haven’t seen on any other cards I own.

See pictures below, I took them with my phone, whilst holding the card up to a 7000 lumen projector displaying a white screen, shows the internals quite well.
Also an AmEx card for reference, same contactless features, much simpler circuitry which you can barely see, nothing as complex as inside the Monzo cards.

Is there anyone from either Monzo, or the community who can shed some light on what it’s there to do, perhaps some future version of contactless I’m not aware of? I’m very intrigued.

(Both cards are expired/invalid, don’t worry.)image image


Curious to know what that chip behind the mag stripe is. I’ve always thought the actual chip of the card is behind the metal contacts, and the contactless antenna goes around. Could be that the actual chip of this card is behind the mag stripe and there are just traces going to the contact pad.


I’m pretty sure that the chip on the Monzo card is the dark area you see above the signature strip. There is a YouTube video with some information, but not specifically about what you are seeing when you hold up your card to a light source :slight_smile:


@GalaxyMergirl will probably know. :wink:


I tore one apart, don’t remember what the dark area was, but it didn’t seem to be any kind of chip, which was behind the contact pad as usual IIRC. It’s been awhile, tho, so don’t quote me…


Some interesting thoughts there. The YouTube video @dave.b linked does give a potential answer, in the section where it talks about the potential for readers to write to the card.

Some more facts, I checked a bunch of cards I had over the last two years against the projector to view the insides without destroying them.

The old prepaid card, pictured above, has the exact same circuitry inside as the card I received with my current account earlier this year, no difference there.

Looking at the Monzo card from the back reveals there is a lot of the circuitry going out of the chip, so I don’t believe it’s just there as a dummy.

All my other brand cards that support contactless only have one ring around the outer edge, and some times smaller circuits crossing the middle of the card, nothing anywhere near as complex as the Monzo cards.

I have also got a joint account once they released it, and I noticed the chip from the front looks different, it doesn’t have the extra metal around it, making it fairly small and compact, same look as the AmEx above. I thought it may be worth taking a look at this one too, and it turns out it’s also very different from the standard monzo cards.

If anyone can comment if they received a monzo card within the last two months, how does the chip look?

Anyways, back to that joint account card, whilst unfortunately I can’t show a picture, as it’s an active card, I have taken a good look, it appears that instead of a few lines going out of the chip from small to big like in the normal card, the joint card has six circuits, all slightly thinner then the normal card, and they all span the full length of the card from side to side, and join back with the main ring around the card, and no big black square at the top, instead it has, I counted, 12 very small squares in a sequence, all strung together by a circuit, right under the signature field. I can’t comment on how they connect back to the main chip, or if they do, as the lines get obscured when looking at them because of the mag stripe right above.

I presume MasterCard won’t be very keen to providing any form of full diagram of the internals of the card, if perhaps someone at Monzo can share what they’re allowed to, I’d be very interested. :slight_smile:

Mastercard doesn’t make the card design. If anything’s proprietary, it’d be to the manufacturer, not Mastercard.

Interesting, do you know who designed the card in this instance? What does the process look like from “I want to start a bank” to “here’s your card”?

There’s some details about the new chip on this thread

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Remind me to look tomorrow at who made the chip, it’ll be stored on the chip. Which is what I actually meant when I said card manufacturer… Who made the chip and antenna combo. This is not necessarily the same people who make the plastic or who print it. There are many steps.

As for the process from deciding to start a bank to issuing cards… That’s much too long for a post and there are many ways to go about it. I will say the fastest is to NOT start a bank if your end goal is to issue cards, but instead to contact with a prepaid card provider. This is what Monzo originally did to launch.


This company make starling and revolut cards. This page gives some idea of the process
This company make monzo cards
Looking at my starling and monzo cards in a bright light, they have many similar features but the monzo card has what seems to be a more sophisticated antenna. They both have the multiple blocks at the top with connections to the chip(s)

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I know Tag Systems makes the plastic but I don’t think they actually make the chip that’s what I’m going to look up later when I get a chance. Also, they don’t finish the card. There are multiple parties involved :slight_smile:

ST. All the specs are on that thread I linked above


My revolut card also seems to have another chip behind the magstripe, Curve, HSBC and Barclaycard card doesn’t appear to