When I started looking at user journeys for CrowdShed.com and the tools we’d need to deliver a good quality UX, one of the first areas I looked at was forms.

Form abandonment is a headache for all ecommerce sites but there is a lot of learning out there regarding how to minimise the risk of alienating users.

This blog looks at some of the core UX requirements that I think people selecting a postcode lookup and validation tool should take into consideration, as well as explaining which solution we chose and why.

In my experience, the primary causes of form anger are (all experienced personally as well), in no particular order:

  • Broken forms – the field just doesn’t work, or the form doesn’t function properly.
  • Lack of clear direction – I don’t know what I have to enter here, or where, or what caused the error.
  • Inflexible flows – I can’t go back without losing all my previous data.
  • Manual overload – you’re killing me with data entry.

These problems are compounded on mobile devices, especially with manual overload because long forms require clever UI designs to stop the user from drowning in a scrolling nightmare.

Address creation and validation are usually top of the list in terms of slowing people down. They affect the two most important online processes; account registration and checkout.

Getting address capture right is a commercial imperative, so my first port of call was to review how leading ecommerce sites handle this, then look at the solution providers behind them.

This blog is an overview of the key requirements that in my opinion define a good quality provider and UX, with examples, followed by insight into which tool we chose and why.

1) Simple lookup vs. predictive search

I’m a big fan of predictive search in address lookup. Why? Because it dynamically updates the list of matching addresses as you type, in the same way predictive search works.

For me it’s a clean UX because the available options refine as you type, avoiding the need to scroll down a list of all matching address for a postcode.

Some websites provide the simple double click lookup: add the house name/number and/or postcode, click “find address”, then select the address from the matching results. M&S is an example of this:


It’s a clean and simple solution but what happens if you don’t know the postcode? I like the predictive UI pattern I’ve seen on sites like Superdry and The Watchshop, especially on mobile.

I’ve done some very basic usability testing of this and predictive has come out top for most people because it follows the logic of how our brains think about addresses (i.e. ask me where I live and I don’t start with the postcode, unless you’re a sat nav device!). The example below is from the Superdry desktop site.

It still amazes me that Amazon doesn’t provide address lookup throughout the site. When I try to add a new address, I have to do so manually yet there is an address lookup for the local collection option.

There is no in-line validation either; the field errors are all displayed after submission. Knowing how much testing Amazon does, I’d be amazed if this doesn’t have a rational explanation, but for me it’s still a negative user experience.

2) International capability

International address management can be complex due to the variety of address formats that a validation tool needs to handle, as we well as the need to handle multilingual search.

For example, can native Welsh speakers type and receive results in Welsh, or does it default to English?

I liked the way brands like Superdry enable this via a country flag drop down list. Once the country is selected, appropriate local address validation rules apply.

3) Location aware

For some addresses, there can be lots of potential matches when using the predictive model. For example, London Road exists in pretty much every town in the UK.

The ability to use geotargeted sorting to prioritise address matches based on proximity helps enhance the user experience and cut down the time to find the right address.

This is particularly important for mobile sessions where long lists are cumbersome and a poor UX has a significant impact on form abandonment.

4) Partial matching

If you don’t know the postcode, how do you use the more traditional types of lookup? They don’t work. Partial matching enables users who know a string of the address (e.g. the building name for business premises) to find matching addresses. It’s not foolproof but it does give greater flexibility to the user.

The example below from Peacocks demonstrates how a user can search for a company name and find relevant address matches even when they don’t know the full address.

5) Coping with spaces and errors

Typing errors are common in web forms. A good example with postcode lookup is entering the letter ‘O’ instead of the number ‘0’ and vice-versa.

At Belron, Craig Sullivan found that this was causing 2.5% of customers to abandon; to solve the problem, Belron's forms were improved to anticipate these errors so that users continued through the form, not even knowing they made a mistake.

However, there inevitably needs to be a trade-off between perfecting error handling and the cost/effort of building a validation engine that caters for all edge cases. If only one person has switched a ‘5’ for a ‘S’, do you really want to spend time and money developing a solution?

6) Mobile

Postcode lookup has to work smoothly on mobile where tolerance for form completion issues is even lower than on desktop. The key requirements are:

  • Large fields to make it easy to tap where you want to type.
  • Large CTA buttons so it’s easy to continue.
  • The form works if you swap to landscape orientation.
  • It’s clear which fields are required and which are optional.
  • The form makes use of native keypads functions and gestures.

John Lewis provides a clean UI design, with large clear buttons to help the user. The form also adapts when the phone switches from portrait to landscape and makes use of native keypad features like the scroll wheel to select the address.

 Hotel Chocolat has implemented the predictive pattern on its mobile site.

7) Daily updates

I remember reading somewhere (in a far, distant land) that there are more than 3,000 changes made every 24hrs to the Royal Mail’s PAF file. It’s essential that addresses aren’t treated as a static asset and that whatever powers the lookup is updated on a daily basis.

For example, how does it cope with recently built properties such as blocks of flats with multiple residency? Without this intelligence, accuracy degrades quickly and customer service issues will creep in.

An essential fall back option is offering users manual address entry but that’s not a replacement for fresh data to power an automated tool, it’s to handle edge cases.

When thinking globally, it’s important to check what local country address data files are being licensed and verified against. For example, in Australia data from Australia Post should be used.

And a key requirement for developers…

8) Testing pack

Before you commit to purchase, you need to find a supplier that supports test accounts. The online demo versions are fine to give you a flavour of how it will work in-situ but they don’t let your developers get under the hood and understand the nuances of implementation.

Postcode validation shouldn’t be a complex development task but assumptions are dangerous, especially when operating within the tight timeframes of a startup.

I looked for providers who would set-up a free test account and had the flexibility to extend the trial period and provide technical support if there were any questions.

Both Address Doctor and Postcode Anywhere, shortlisted from the core feature review, satisfied this requirement.

Which solution are we implementing?

We’re going with Postcode Anywhere’s Capture+ because it ticked the key boxes (especially around international as I don’t want to have to swap solutions in six months) and we found the support team responsive and helpful.

I had the benefit of knowing Capture+ well before I did the research because I’ve been a guest blogger for Postcode Anywhere for the past 18 months. I say this simply for transparency; it has in no way influenced the content of this blog, or indeed my decision to invest in Capture+ for CrowdShed.

In my research Capture+ came out top in overall scoring for core UX, solution flexibility and ease of implementation.

Other solutions like Address Doctor did trump them for some criteria but Postcode Anywhere has a raft of updates to roll out in 2014, including handling user errors like typing letters instead of numbers.

There are several write-ups online regarding the impact of Capture+ on ecommerce conversion rates and customer service, which helped inform the decision.

The article in Computerweekly.com discussing the implementation at Reiss is worth reading (though dated June 2013) even if the comments aren’t compelling. There are lower cost solutions out there but our decision was based on value for money, not just cost.

My advice is to do a simple cost/benefit analysis; compare the potential uplift in conversion/revenue from an enhanced postcode validation tool vs. the additional cost.

I can’t yet validate the impact on form completion and conversion for CrowdShed because the transactional site launches in September but I do know from working with many B2C and B2B clients that postcode validation, when done well, does increase form completion rates.

What do you think?

Please drop by and share your comments, questions and experience. Which solution do you prefer and why?

Please also share any relevant links you think fellow readers would be interested in.

James Gurd

Published 14 August, 2014 by James Gurd

James Gurd is Owner of Digital Juggler, an ecommerce and digital marketing consultancy, and a contributor to Econsultancy.He can be found on on Twitter,  LinkedIn and Google+.

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Comments (21)

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Interesting article - being a startup, I thought you would have taken a look at http://postcodes.io/ (an open source Postcode database) it's free and really would mean that you're not restricting yourself to one vendor's functionality set - so you could define and own the postcode lookup experience yourself.

almost 4 years ago

Pete Fairburn

Pete Fairburn, Managing Director at morphsites

Great article.

Convention wisdom with address/postcode lookup is to think that it will automatically make life easier for the user if implemented instead of having to manually enter the addresses. However, poorly design interfaces can lead to frustration and abandonment where a simple address form would not have!

I also agree that inconsistency in where address lookups are implemented on the same site are baffling, particularly where the sales funnel is concerned.

We've used www.postcodesoftware.net for several websites successfully. The API is simple, includes a test dataset and the costs are competitive - less that 2 pence per lookup.

However, I am impressed with Postcode Anywhere's Capture+. While it is more expensive, I suspect the resulting improvement in user experience will more than pay for itself in terms of greater conversions. Thanks for the tip, we will be trying it and will will report back!

almost 4 years ago

Pete Fairburn

Pete Fairburn, Managing Director at morphsites

@Rob, open source is great, and http://postcodes.io looks promising, we'll certainly take a look.

However, there have been cases in the past where the Royal Mail took exception to their Postal Address File (PAF) data being given away for free when it has commercial value and shut previous free providers of this information down.

Concerns over service reliability also need to be considered.

This would be quite an exposure for a larger ecommerce operation, particularly where address lookup failures due to a service or licensing issue could quickly become terminal for online revenues.

almost 4 years ago

Albie Attias

Albie Attias, Ecommerce Director at King of Servers Ltd

Good stuff as always James. Would add inline validation to the requirement lists for form handling - nothing more frustrating than submitting a long form only to find a load of errors on page reload, particularly when the entered data hasn't been retained. Check for valid entries at the point of entry where possible.

almost 4 years ago

James Gurd

James Gurd, Owner at Digital JugglerSmall Business Multi-user

Morning all,

Thanks for the comment.

@Rob - yes i am aware of it but i have a concern with OS that there is no guarantee of the ongoing maintenance and data accuracy across a global set of databases. OS is a wonderful thing in many ways but getting address management as accurate as possible is critical to our site and we saw this as a potential risk.

It is also only updated quarterly - for me that's too slow for the accuracy we want. So in this case, we decided investment was better than free. As a regulated business, ensuring we have accurate and validate address information is critical.

As i said, time will tell if we made the right decision.

@Pete - i didn't look at www.postcodesoftware.net but will keep that on the list for future reference, thanks.

Yes Capture+ has the best UI design i've seen but as you point out, the implementation approach is what makes it work. I've set myself up for a fall now!


almost 4 years ago

James Gurd

James Gurd, Owner at Digital JugglerSmall Business Multi-user

Hi Albie

Yes very good point, though inline validation would apply more to the manual form than the lookup (unless your lookup tool is populating invalid data in which case it's time to cry!).

I guess where it does help is for the double click method, rather than predictive. So if you enter an invalid postcode, it tells you rather than saying "mo matches".


almost 4 years ago

Mark Selwyn

Mark Selwyn, eCommerce and Multi-Channel Retail Consultant

I came across an error message last week that said "Postcode Letters must be in Capitals". Huh? Whys that then? You got some secret squirrel case sensitive postcodes on your database?

That then gave an unspecified error, which I cured by putting a space between the first bit and the last bit.

Very poor.

almost 4 years ago


Adam Stylo

Hi James,

I work for a Royal Mail PAF reseller (Crafty Clicks).

I think the simple postcode lookup is still a better UX that the predictive search, two reasons:

1/ With simple lookup, number of keystrokes to full address will be lower. If your users start with anything but the postcode, their jurney will be slower. The case where the user doesn't know their postcode will be extremely rare and can be handled sepatately.

2/ The UI of input box + "Find Address" button is just so clear, obvious and familiar in UK. Users know what to do in a split second. Predictive input box needs explanation to be used quickly, users are likely to need a pause to figure out what to do. I think it may fall into your "Lack of clear direction" category....

One thing I completely agree with you on is that the old way of having the user type the whole address by hand in the UK is just not acceptable now. You make your users work hard and end up with poor quality data.

On the international side, the data quality and availability can be an issue - there are countries with great data, but mostly it is much poorer than we are used to in the UK. Personally, I think the right approach there is post-entry validation. Let the users go through checkout with a familiar UX and don't distract them with potentially poor suggestions. Then, once you clinched the deal, check the address and put up a UI to alert the user and give them a chance to fix their address (or not!).

Thanks for raising the topic up for discussion!


almost 4 years ago


Sarah Alder

Really useful post. And it did make me chuckle that your example under International was Welsh. Thanks James.

almost 4 years ago

James Gurd

James Gurd, Owner at Digital JugglerSmall Business Multi-user

Hi Adam

Thanks for dropping by. I know of Crafty Clicks, did actually take a peek but Capture+ won for me because i've seen better feedback in (albeit simple) usability studies for predictive.

I wouldn't want to handle known uses cases, like not knowing the postcode, separately. The cleanest solution IMO is one that caters for as many use cases as possible in one place. And i think predictive is actually a clear and intuitive UI because that's how people have been used to searching for a long time - the Google predictive search pattern is so familiar and now replicated across lots of ecommerce sites, hence why predictive postcode lookup isn't a new concept for people to get their heads around.

I've not seen any evidence of predictive making people stop and consider what's going on, in fact quite the opposite. They just start typing and the tool does the rest for them.

But of course, not every site and audience respond exactly the same.

As you say it's good to have a discussion and my view point is one of many, so thanks for adding your perspective.

@Mark - that's a crazy validation! I'd love to see the drop off rates for that form.


almost 4 years ago



Great article on one very specific area of the shopping cart!

One thing that annoys me as a user is when the address is split up into too many lines or there is too much validation.

For instance (seen more in Australia than the UK) I've seen

1. Flat Number
2. House Number
3. Road Name
4. Road type (eg crescent, street, parade)

It's very annoying and counter-intuitive when trying to type your address.

As for "too much validation" sometimes it's best to do the validation server side after submit - if I want to type "Saint Johns Road" or "Arthur Cres." then it should let me, ideally, and sort it out on the server side. Equally, I might have something that isn't on the data file - it shouldn't spit up an error if my house isn't on there.

One really vital aspect of address validation is data hygiene, this is particularly vital when you've got a CRM and you want to make sure everyone matches up.

Does anyone have any hard statistics about the uplift in conversion from address validation? I've seen a few bandied around by the people that make the software (hello QAS)

almost 4 years ago

Pete Austin

Pete Austin, Founder and Author at Fresh Relevance

One of my friends always uses the wrong postcode, because his address was given a new postcode after he moved in, but he missed the notification. (A lot of houses were built around him, so his original postcode area was split into several areas.)

Deliveries mostly work, because he's very close to the area with his original postcode, so although he complains about occasional misses he refuses to believe there's an underlying problem.

I suspect there are quite a lot of people like him - especially older folks - so it may be a good idea to make sure your UI allows invalid postcode/address combinations.

almost 4 years ago



A very thorough and informed comparison of the various methods of address form completion. I agree wholeheartedly that this sort of service is imperative for mobile users and is unfortunately often overlooked.

However, I find it hard to believe that your 18 months' experience writing for Postcode Anywhere had no bearing on your recommendation.They're not exactly going to welcome you back with open arms if you suggested someone else. I doubt Microsoft would be too chuffed if Bill Gates suddenly started banging the drum for Apple.

You mention that Address Doctor are superior to Postcode Anywhere in certain regards and then do not describe how. It would be helpful to know which providers you looked at and what they did well and what they didn't. I notice that Address Doctor do not offer the real time address completion feature you seem to like. Why not compare Postcode Anywhere to someone who does? Allies Computing also offer this, for example. Coincidently, their matching engine already handles user errors like zeros typed in place of "Os." You also mention that there are cheaper solutions available- you could compare the functionality of Postcode Anywhere's Capture+ to one of the low cost alternatives, like Craftyclicks. You don't exactly give much justification as to why Postcode Anywhere offer more "value" than the cheaper alternatives. As a start up, the all-encompassing solutions (bank validation etc.) offered by QAS may not be within your budget just yet. Yet, if they allow for a trial, it would be interesting to learn how Capture+ stacks up from a technical and usability perspective.

You can find a comprehensive list of addressing solutions providers on Royal Mail's website: http://www.poweredbypaf.com/end-user/?ltr=0#SL

almost 4 years ago



Thanks for the article. We are in the process of deciding on the postcode validation provider. Will report later this year how we are doing and how it's impacting the conversions.

On another note; Just read (not the whole thing yet) the 'Age of Impatience' report. Then I went to the Address Doctor website to check their offering. I think they seriously need to consider how the info is presented on the website - contacting them isn't easy either. Out of desperation I even called the UK number. No answer. One less provider to consider.


almost 4 years ago

James Gurd

James Gurd, Owner at Digital JugglerSmall Business Multi-user

Hi @Oscar

I can honestly say it had no bearing on my choice other than i knew who to speak to when my developers had questions, rather than with other providers where that door wasn't as open. As a Director and shareholder of a company, i would never choose a solution that wasn't in the best interests of my company, that's not how to do business. I also know a lot of people in the industry who i talk to to learn what they think, through personal connections and #EcomChat - Capture+ has had a lot of v good feedback and that influenced my decision more than anything a company could say to me.

Re the comparison, i deliberately shied away from this to focus on the UX requirements because that enabled me to be impartial and look at what delivers the best online experience. That to me is the starting point for any decision re solutions - find what's best for the users, then work back and review the technical and financial compatibility.

Value for me is defined as a combination of factors:
* End user feedback - from some basic usability i've done in the past
* Data from people i've worked with showing the impact of predictive lookup on form success
* Quality of the UX
* Cross device capability - i don't need different solutions for mobile, desktop etc.
* Ease of implementation - that was for my developers to tick off
* Cost of service
* Reliability & scalabilty (in terms of supporting long term growth plans).

As a startup we didn't have the luxury of a large team to go and review the full market. I started with 4 providers based on prior experience and went from there. I'm sure i've not looked at some vert good solutions but launching a new business is about being pragmatic with your time.

Thanks for feedback and the list of solution providers, very helpful for other readers.


almost 4 years ago



Here's an interesting challenge. Can we get a mobile device to switch between keyboards automatically when entering a postcode? There are some special cases particularly in London but it would be a great problem to solve.

almost 4 years ago


Mark Selwyn

Not sure how it would switch eg an LS2 postcode v an L2 postcode.

What about a radical idea like a mobile keyboard with both numbers and letters on.

almost 4 years ago



It should also be compulsory for all predictive address forms to include the option to enter manually. I have had to abandon purchases in the past as postcode finder has been unable to find my complicated address within a block of flats.

almost 4 years ago

James Gurd

James Gurd, Owner at Digital JugglerSmall Business Multi-user

Hi @watson

Yes definitely a manual option should be on every postcode form anywhere by default.

And it's such an easy option to add.


almost 4 years ago


Lee Smith, Developer at getAddress.io

Have you seen https://getAddress.io ?

It doesn't meet all of the features above but these are exactly the goals we're working towards.

over 3 years ago

Stephen Keable

Stephen Keable, Customer Experience Designer at Allies Computing Ltd

@JamesGurd just wondered if you have any links to the studies you mention in "i've seen better feedback in (albeit simple) usability studies for predictive"

almost 3 years ago

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