thread Re: Invalid postcode in Payments Troubleshooting

Invalid postcode

MODmag — Sun, 21 Sep 2025 13:13:55 GMT

Hi there,

I have had a couple of customers who have complained that they've been told their postcodes are invalid when trying to checkout. One of these customers persevered and it eventually worked but he said he didn't do anything different. The other cannot make it work despite trying different browsers, making sure it is inputted in upper case without spaces and has tried different payment cards.

Any ideas?

Many thanks

Re: Invalid postcode

tranguyen — Thu, 15 Apr 2021 09:57:41 GMT

Hi @MODmag, sorry to hear you are running into this issue! This might be something that our Support team can look into further as they can check the specific transactions and see what might have caused the error.

You can find information on how to contact our team directly here. When getting in touch, please let them know the transactions attempted, where the issue is occurring (on Square Online site, checkout link or a third-party integration) and our team will be able to help.

Re: Invalid postcode

Kazzer — Wed, 07 Jul 2021 12:59:36 GMT

Hi Did this issue get resolved as I have also received this error from a customer.

Re: Invalid postcode

tranguyen — Wed, 07 Jul 2021 16:28:46 GMT

Sorry to hear you're running into this too, @Kazzer!

If the customer has made sure there is no space between or after their postal code, and that it is all in upper case but the error message still occurred, it's best to contact our Support team directly. This way, our team will be able to heck the specific transactions and see what might have caused the error.

Re: Invalid postcode

LathamA — Wed, 08 Sep 2021 16:50:40 GMT

I'm getting reports of similar problems with entering UK postcodes when making a payment. If there is special instruction like capitals and no spaces required it should be spelled out on the form - otherwise it leads to frustration and distrust of Square

Re: Invalid postcode

Sam_400º — Wed, 08 Sep 2021 19:20:59 GMT

@tranguyen wasn’t this being looked into so the system would ignore any spaces in there?

If I remember right as it’s part of the card confirmation security it was more complicated but worth pushing if we can.

Re: Invalid postcode

tranguyen — Thu, 09 Sep 2021 08:11:33 GMT

Thanks for tagging me in @Sam_400º!

I actually got some clarification from the team after the last Square Online Q&A - Square does allow for postcode to be entered with or without a space, but we're constraint by requirements from credit card companies themselves since they'd need to verify that the details enter match what they have on file.

@LathamA - I've sent you a DM just to get a bit more information on the error you're experiencing so I can look into this further.

Re: Invalid postcode

Sam_400º — Thu, 09 Sep 2021 08:52:46 GMT

The validation problem seems to be the space after the postcode when a phone/tablet auto fills.

Could the square side not remove any space before sending to be validated?

Re: Invalid postcode

LathamA — Thu, 09 Sep 2021 09:29:45 GMT

Last evening the customer who had had the problem, who previously had got around it by only putting the first part of his postcode, got the message that his address was invalid. he switched from Google Chrome to Micosoft Edge and then had no problem, so possibly a browser issue.

Re: Invalid postcode

tranguyen — Thu, 09 Sep 2021 09:32:09 GMT

We checked in with the team previously about having a feature like this @Sam_400º but I don't think it was likely at the time. Let me check in with them again and see if there's another way we can do something to strip the space after the postcode when it's autofill.

Re: Invalid postcode

tonydow — Thu, 09 Sep 2021 10:34:30 GMT

Hi Tra. If someone pays for an item using a credit card with the Square Reader or similar, there is no reference to their postcode. Similarly, if I buy anything using a credit card. Why then is this an issue when checking out. I may be missing something, but would be interested to know. Thanks

Re: Invalid postcode

tonydow — Thu, 09 Sep 2021 10:55:54 GMT

@tranguyen Could you please define EXACTLY what is acceptable to Square with regard to postcodes.
1. Spaces within and/or after

2. Case sensitivity

Thank you.

Re: Invalid postcode

tranguyen — Thu, 09 Sep 2021 12:28:35 GMT

Hey @tonydow, when customers are paying with a Square Reader or similar devices, they are paying in person so postal code is not a requirements, as they will be able to verify the purchase using their PIN number or a different method (if they are using Apple Pay or Google Pay).

When customers are paying online, we do need more information in order to verify the purchase. The information asked for are card number, expiration date, CVV and postcode. Some places may ask for the full billing address but currently, we only require the postal code to verify.

From checking in with our team and doing a couple of tests, there have been some improvements made: the postal code will be accept in both capital and lower case, with and without space. The only remaining issue is if there's a space at the end, then it'll come up as invalid.

I hope this will help in some ways!

Re: Invalid postcode

tonydow — Thu, 19 Jan 2023 15:28:33 GMT

Would it be possible for Square to use the following REGEX expression to remove trailing spaces when evaluating the postcode:

/.*(?= |$)/

Tony

Re: Invalid postcode

Breffni — Fri, 20 Jan 2023 09:35:40 GMT

Hello @tonydow, thanks for raising this.

I'm not sure if this format is something that would be changed by our teams as I'm not sure about the implications on a larger of this sort of feature, I will flag it as a request nonetheless!

Re: Invalid postcode

tonydow — Tue, 27 Jun 2023 14:25:31 GMT

Another regex to validate UK postcodes. Accepts upper or lower case, space (or no space) between elements and ignores trailing spaces:

/[A-Za-z]{1,2}[0-9A-Za-z][0-9A-Za-z]?\s?[0-9][A-Za-z][A-Za-z]/g

Re: Invalid postcode

vse1 — Sun, 12 May 2024 08:10:39 GMT

Came across this same issue yesterday with a customer. They eventually got it to work on the third attempt of deleting and reinputting the post code. This is concerning as just joined square with a new venture and cannot afford to have potential customers walk away from a sale who face this issue. Are there any updates on this?

Re: Invalid postcode

Lou8 — Tue, 14 May 2024 12:48:26 GMT

Hi @vse1, thank you for your post and welcome to the Community 👋.

Did you customer used Apple Pay, Google Pay or Square Pay to pay, or did they manually enter their card details and information at checkout ?

Re: Invalid postcode

StyleHouse24 — Wed, 03 Jul 2024 22:37:06 GMT

I am experiencing this same issue with customers and I am quite perplex how it has been left to go on for so long with how long Square has been established now. Customers that have persevered with checking out are advising that they are only successful in checking out by entering the post code in all lower case letters and a space in between. Now i am concerned how many customers are abandoning checkout because of this issue and not feeding back. Is there a fix for this yet please?