The problem with a free address lookup API.

Postcode Address Lookup API image.

Whilst building the EasyPostcodes service we did consider different sources for the data. UK postcode address data is available from different sources. Some are free, some are cheap, and some are paid-for. The question always came back to what kind of service we want to offer our customers. Do we want to provide a cheap service or a good service. In the end, we decided to offer our customers a good service rather than a cheap postcode address lookup API service.

We tested a few cheap solutions on the Internet, and we found that the latest addresses were not available on them. Whole postcodes were missing because the data is not up-to-date or accurate. It is important to know where the data comes from and how frequently it is updated before signing up for a postcode address lookup API service.

Sources of address lookup data.

In the UK, one can obtain the postcode address file from sources such as the Ordnance Survey for free. It is public data, and you can obtain it for free. So initially that was an option. The issue with obtaining the free version of the address file is that it is on average at least one year out of date and not entirely accurate. Also, that would mean the only value we provide is to make that data available via an API, which there are already free services for, such as GetTheData So when you come across a cheap or free address lookup service, check where they get the data from. If it is from Ordnance Survey, then it will not be entirely up-to-date because there is a process that an address goes through, from the date it is built to the date it is available on the Ordnance Survey data file, which can take up to a whole year.

On the other hand, the Royal Mail address file is updated daily, but it does cost, hence the paid-for services are a bit more, because the data is more accurate.

When to choose a free or cheap address lookup API service?

If you need to make some calculations, some estimates or averages, and you just need a good data sample, then it makes sense to use free data for that. Given that paid-for address lookup services charge per request, it can become quite expensive to use the data. Therefore, if you need to simulate some case scenario and you need loads of addresses, then definitely go for the cheap or free data. As long as you know that the data is somewhat out of date, and you are happy about that. If you are providing goods or services, then you might need a more complete set of data than that.

When to choose a paid-for address lookup API service?

If you are a retailer serving customers, then you need accurate and up-to-date address lookup data. There is no end to the frustration that some customers experience when their goods are delivered to the wrong door, just because they are in a new-build. Also, it is frustrating to the operator when serving a customer when they cannot find the address. There are thousands of Royal Mail postmen and women roaming the whole country on a daily basis. The Royal Mail postcode address file receives thousands of corrections a day. So, if you need accurate and up-to-date postcode address lookup data, then the Royal Mail Postcode Address File (PAF) is what you are after, and that is what is powering our API.

We made the decision to cater for customers who are after up-to-date and accurate address lookup data and hence we partnered with Royal Mail, probably the most accurate and up-to-date address lookup file in the UK. We also host our service on the cloud to ensure uptime and service resilience.

Our support is great and always there for you and it is included in the price.


So the main problem with free or cheap address lookup API services found on the internet is that they use the free data set and market it as an accurate and up-to-date data set. Having tried it ourselves, we found that the latest postcodes are not on there. If you use it and it does not return any results, do not assume that the postcode used does not exist. It does, it just they are behind about a year from the current state of address data.

Having looked at the kind of prices in the market at the moment, we have decided to provide just the core service at a reduced rate. The core service is to get the list of addresses against a given postcode. That is what we offer, but at a much reduced rate than our competitors, all the while giving you up-to-date and accurate data.

We’d love to hear from you.

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