By Peter Ramsey

12 Nov 20

Making a payment Company Logo
UX of Payments
10 min read

Making a payment

Making a payment Featured Image

The experience of making a payment is undeniably the most important user journey for these services.

It’s a process that on the surface looks very simple to build, but is subject to awkward use cases which make it incredibly difficult to get right.

Which of these payment service providers has the best experience—for both the employees, and the customers?

Let’s dive in.

Summary: Most iZettle, Square and SumUp customers would save money by switching to Verifone. But that doesn’t mean they should.

Key takeaways

  • 🙋‍♂️

    Why you’ll need to turn off your phone’s notifications.

  • 🏝

    Why Verifone isn’t suitable for everyone.

  • ⚡️

    How (not) to time permission modals.

  • 👈

    SumUp’s lack of an undo button.

  • 👀

    Why the consumer benefits from a screen.

  • 🌍

    The problem with using Square at a car boot sale.

Case studies

Benchmarking the experience

These services make money by charging you a fee as a percentage of every transaction. So if you sell a coffee for £3, you’ll pay a few pence.

Percentage fee (on my package)









And although the difference between 1% and 1.75% may seem insignificant, it quickly becomes noticeable.

Here are three scenarios, showing what the total costs would be in the first year of usage, including purchasing the card reader.

Estimated year 1 costs (device + card transaction fees)

£500 in monthly revenue (12 months)


£2,500 in monthly revenue (12 months)


£5,000 in monthly revenue (12 months)


Total cost for 12 months (GBP)

At £5,000 in revenue per month, Verifone will save you hundreds of pounds every year.

These prices don’t scale infinitely though—they all offer custom pricing to larger companies. But how much do you need to be making before iZettle, Square and SumUp will even consider giving you a discount?



Sum Up

Advertised monthly turnover to qualify for a discount.




Annual savings at that point if you were with Verifone.




And how realistic is it for a small business to ever reach these thresholds?

A recent study suggested that 43% of cafes have a revenue of less than £100,000—the minimum required to even be considered for SumUp’s custom pricing.

And for many industries—like those who sell homemade goods at weekend events—£100k in annual revenue is well out of reach.

I think it’s reasonable to suggest that many—if not most—of iZettle, Square and SumUp’s customers could save money by switching to Verifone.

Essentially, customers are paying for access to the iZettle, Square and SumUp apps. That begs the question: are they worth it?

The experience

Here are 6 ways that these services could improve their UX.

1. Handing your phone to strangers

Square’s entry-level device stands out for a few reasons, one being that it doesn’t have a keypad.

So, when contactless payments aren’t suitable, the user needs to input their PIN number on the device that the seller is using.

Not only does entering your PIN number into a strangers mobile phone require a serious level of trust, but it’s also uncomfortable for the seller.

“Okay, enter your PIN when ready, please don’t read my messages”.

And yes, you can still receive notifications while on the PIN-entry screen.

Ann Summers1
Ann Summers

How many people would feel comfortable passing their mobile phone back and forth between customers all day?

And as a customer, how would you feel knowing that the seller probably plays with their ‘card reader’ on the toilet?

2. A virtual basket

“Can I have 3 lattes and two shortbreads please?”

This introduces a new variable: selling multiple items at once.

If you’re using Verifone—and hadn’t invested in any additional retail hardware—then your only choice would be to add up the value of these 5 items, and then type the total amount into the card reader.

And this is where the software of iZettle, Square and SumUp can demonstrate why it may be worth paying for—they offer virtual baskets.







Being able to add items into a basket like this fixes a number of user experience issues that Verifone face:


No calculators required

i.e., it adds it up for you, and gets it correct every time.


No need to remember exact values

i.e., was adding cheese to the burrito +20p or +30p?


Therefore, sales are quicker

i.e., so you can serve more customers in an hour.

For some, not offering this feature would be a deal-breaker. It’d depend on how complicated your sales were.

3. Timing permissions modals

In most instances, you want to ask the user for permission to access their data in the context of doing that action.

i.e., only asking for permission to access their photos at the point that they are trying to add a photo.

But there are a few exceptions, including this one:

Don’t ask for permission for something at a moment of high intensity—such as while making a transaction.

iZettle require access to your location in order to accept card payments, which feels totally reasonable. However, they ask for your permission whilst you’re making your first sale.

null image

In the excitement of making a sale, you may be surprised by this request and click ‘Don’t Allow’ out of habit. Perhaps you didn’t even read what it was asking for.

And what would happen if you did accidentally click ‘Don’t Allow’?

Well, the modal closes, and it looks like the payment can go ahead. But when the customer taps their card…

IMG 4282
I Zettle Permish2
I Zettle Permish3

If this happened during a real transaction, then you’d have to ask the customer to wait while you dive into your iPhone settings.

Instead, iZettle should request this permission before the sale is initiated—perhaps when they’re connecting the card reader. If nothing else it’d help avoid any potential embarrassment.

4. Cancelling a payment

Imagine that you’ve initiated a payment, but before the customer taps their card, you realise that you’ve entered the wrong amount.

You’d obviously want to cancel the payment and start again.

But with SumUp, this is more awkward than you’d probably imagine. You only have two options:


Wait 60 seconds

After which it’ll automatically cancel the payment.


Click a physical button on the card reader

It’s the power on/off button.

Or rather: you can’t cancel a transaction via the app. Instead you’re left starring at this inescapable screen.

null image

This is a process that you can only initiate using the application, and then only cancel using a separate device.

There are obvious reasons why this is frustrating, but perhaps the most practical one is that the card reader might not be in your hands—it might even be in your customer’s hands.

And as Covid-19 changes the way we interact, it’s entirely possible that the card reader is on the ‘customer side’ of a sheet of perspex.

5. Tap whenever you're ready

There’s a light on my oven which tells me when it’s pre-heated to the correct temperature. However it’s entirely useless to me, because I can never remember if the light goes on or off when it’s ready.

And that’s the problem with a single and unlabelled LED—you never know if ‘on’ is good or not, or what it does.

With that in mind, look at the ‘ready to pay’ states for each of these devices:

I Zettle Tap
Square Tap
Sum Up Tap
Verifone Tap

With Square’s device, how does the customer know when to tap their card?

Sure, in a nice and relaxed coffee shop the employee could say “tap your card when you’re ready”. But in a chaotic, noisy and under-staffed environment, that may not be possible, or audible.

The screen acts as a visual cue. It’s not really for the benefit of the employee, but for the end customer. It’s a subtle signal that helps the logistics of every transaction go slightly smoother.

And as an example of how important these cues can be, imagine if there was no beep sound when making a contactless payment. How would you know when to withdraw your card?

You wouldn’t, and it’d be annoying.

6. The other benefit of the screen

But knowing when to pay isn’t the only benefit of a screen. There’s something else it does which is so obviously important that it’s hard to imagine how a device like this could exist without one.

The screen shows the user how much they’re about to pay.

Imagine that you’re on holiday in a foreign country, at a Christmas market stall. You know that you’ll never return, you don’t speak the native language and you’ll have no way of contacting the seller ever again.

Would you feel comfortable making a contactless payment without seeing the value of the payment on a screen?

Consider this:


Not every bank has immediate push notifications

I did the research, they don’t.


The seller may not show their screen

i.e., the app says what the payment amount is, but the seller could just not show the buyer their screen.


Language barriers

i.e., the verbal nuance between 6 and 16 sound very similar in some languages. But numbers are universal.

As a customer, buying something through a screen-less device requires trust. Why would any seller make it harder for themselves to make a sale?

In some contexts—such as the Christmas market above—Square’s device is so basic that the general user experience suffers.

I’m repeating myself, but I need to clarify this here: Square do offer a reader with a screen, it just costs £199.


Most iZettle, Square and SumUp customers would save money by switching to Verifone. But that doesn’t mean they should.

I’d argue that the software that these services provide are not optional, they’re almost essential to run a retail business in 2020.

And it’s also hard to recommend the entry-level card reader from Square. Sure, it’s £10 cheaper than the others, but the utility of the keypad and screen are far more valuablethan that.

The bottom line here is this: building a great payment experience is hard. In a test environment, sure, you can build one that’s awesome.

But then you put it into the real world—which is full of chaos, noise and employees who don’t read instructions—and you notice the gaps.

These UX edge cases can, and likely will, be softened over time. The real question is whether or not the incumbent providers—who currently have no real software—will ever catch up.

In the next chapter we’ll look at this software in more detail.

Study Complete

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All of the UX analysis on Built for Mars is original, and was researched and written by me, Peter Ramsey.

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