Postcoder vs Data8, Fetchify, Ideal Postcodes and Loqate

All five offer validation features beyond address lookup, though the range differs. All offer email and phone number validation, in addition to address lookup and autocomplete. Postcoder, Data8, Fetchify and Loqate offer bank account validation and sort code validation as well.

Postcoder offers email validation, mobile phone validation, bank account validation and one-time passcode (OTP) verification — all accessible through the same API. OTP verification is not offered by any of the other four providers here, and is useful for identity checks during onboarding or high-risk transactions.

For teams looking to reduce the number of suppliers they manage, Postcoder's range of features through a single API is worth factoring into the evaluation.

Most of the API providers offer an enhanced SLA. The specific terms vary, and not all publish them publicly.

Postcoder guarantees 99.99% uptime, includes service credits if that guarantee is breached and provides 24/7 support as part of its enhanced SLA. Loqate offers a 99.95% uptime guarantee, also with service credits and 24/7 support. Fetchify and Ideal Postcodes both confirm enhanced SLA options but do not publish specific terms. Data8 does not confirm enhanced SLA options but states it will consider SLAs on the Gov.uk digital marketplace.

If contractual uptime commitments matter to your team, Postcoder and Loqate are the most transparent starting points for comparison.

Postcoder offers custom T&Cs and support packages for enterprise customers. Ideal Postcodes advertises flexible terms for enterprise customers. Loqate notes that amendments to T&Cs will be considered, though its products are designed to be off-the-shelf.

Postcoder, Data8 and Ideal Postcodes all offer live chat, email, a contact form and telephone support. Loqate offers email, a contact form and telephone but not live chat. Fetchify offers a contact form and telephone only.

Several providers go beyond a standard username and password.

Postcoder offers multi-factor authentication (MFA), multiple user accounts and SSO (single sign-on, currently in development). Data8 offers MFA and SSO. Loqate offers MFA, passkeys and multiple user accounts. Ideal Postcodes supports passkeys. Fetchify does not publish details of enhanced account security features.

For teams managing access across multiple users, or operating in environments with compliance or audit requirements, Postcoder, Data8 and Loqate offer the broadest set of controls.

All five offer a free trial:

• Postcoder: 30 days, with the option to extend if you need more time
• Data8: 14 days
• Fetchify: 30 days
• Ideal Postcodes: 30 days
• Loqate: 45 days

If you're running a thorough evaluation across multiple providers or have a complex integration to test, Postcoder's willingness to extend trials removes the time constraint.

Four of the five publish their pricing publicly: Postcoder, Data8, Ideal Postcodes and Loqate. Fetchify requires you to request a quote.

Postcoder publishes nine pricing tiers covering both pay-as-you-go credits and monthly plans, with a detailed list of per-endpoint credit costs so you can estimate your spend before committing. Data8 publishes three tiers. Ideal Postcodes and Loqate each publish five.

Transparent pricing simplifies evaluation, particularly for smaller teams without the appetite for a lengthy sales process.

Postcoder is the only API here that offers both models. You can buy credits in advance and use them as needed, or commit to a monthly plan which offers predictable costs and provides better value when usage is consistent.

Data8, Ideal Postcodes and Loqate offer pay-as-you-go only. Fetchify's payment options are not confirmed publicly.

PAF is Royal Mail's database of postal addresses in the UK. It contains every address that Royal Mail delivers to, including residential, commercial and mixed-use premises.

All five address lookup APIs on this page use PAF as the basis for their UK address data. When someone looks up their address using any of these products, the addresses they see come from the same underlying source.

PAF sets the standard for what counts as a valid, deliverable address in the UK. Basing your address data on PAF means your records align with what Royal Mail recognises, which reduces failed deliveries, returned mail and the customer service costs that come with inaccurate data. It also makes it easier to match and merge address records across systems, since everyone is working from the same reference.

PAF is widely regarded as the most comprehensive and authoritative source of postal address data in the UK. Royal Mail updates it daily to reflect new developments, address changes and postcodes being brought into use.

There are some natural limitations worth understanding. There is an inherent lag between a new property being built or a new postcode being assigned and that information appearing in the database, particularly relevant for brand-new housing developments. These properties are listed on an additional database, called Not Yet Built. Many use cases such as utilities providers or delivery companies will require incorporating Not Yet Built addresses into their validation process. Properties that share a delivery point, such as multiple flats in the same building, are handled through another supplementary dataset called Multiple Residence, which some APIs include as standard and others offer at additional cost.

For the vast majority of addresses and use cases, PAF data is accurate and reliable.

Both are unique identifiers attached to address records, but they come from different organisations and serve different purposes.

A UPRN (Unique Property Reference Number) is generated by GeoPlace and allocated to an address by the local authority. Every addressable location in Great Britain is assigned one — residential properties, commercial buildings, places of worship, public spaces and more. Every UPRN has an equivalent national grid reference from Ordnance Survey. Because UPRNs are tied to locations rather than postal delivery points, they persist even when an address changes, a building is subdivided or a postcode is updated. This makes them particularly useful for matching and linking records across different systems and datasets over time. Ordnance Survey (OS) data products such as AddressBase and the National Geographic Database (NGD) are a trusted data source of UPRNs.

A UDPRN (Unique Delivery Point Reference Number) is issued by Royal Mail and sits within the Postcode Address File (PAF). Where a UPRN identifies a location in the broadest sense, a UDPRN identifies a specific point that Royal Mail delivers to. Every entry in PAF has one, and because PAF is the basis for address lookup in the UK, UDPRNs are often used to identify and reference specific address records within a lookup system.

In practice, both identifiers are valuable, but for different reasons. UPRNs are better suited to long-term property data management, cross-system record matching and anything involving spatial or geographic data. UDPRNs are more directly tied to postal delivery and are useful when you need a persistent reference to a specific PAF entry.

All five address lookup APIs on this page return both identifiers, though pricing and availability vary. Some include them in standard lookups, others offer them via specific endpoints at additional cost.

Address autocomplete provides matching address suggestions as someone types any part of their address or postcode. It reduces the amount of typing required and is particularly useful for creating a fast, fluid checkout or registration experience.

Address and postcode lookup returns a list of accurate addresses after someone searches using a postcode or address fragment. The user then selects the correct result to complete the form.

Both approaches reduce errors and speed up address entry. Autocomplete offers a more immediate experience, while postcode lookup provides a familiar search-and-select journey. Most APIs on this page offer both methods to allow development teams to create the most effective solution for their use case. Loqate only offers address autocomplete.

PAF covers postal addresses across the whole of the United Kingdom, including Northern Ireland (BT postcodes), as well as the Crown Dependencies — the Channel Islands (GY for Guernsey, JE for Jersey) and the Isle of Man (IM postcodes). Since all five APIs on this page use PAF as their UK data source, lookups for addresses in these areas are supported.

It's worth noting that some edge cases exist. Addressing conventions can vary slightly in Crown Dependency locations, and certain data points available for mainland UK addresses may not be available for all addresses in these areas. If coverage here is critical to your use case, testing a sample of addresses before committing to a provider is a sensible step.

When a new postcode doesn't yet appear in PAF, address lookup APIs will typically return no results. This isn't a fault of the API, it simply reflects the fact that PAF is updated on a regular cycle and there is a window between a postcode being assigned and it appearing in the database.

New postcodes are often assigned before the properties they serve are built or occupied, which means the gap is usually temporary. In practice, this is most likely to affect users in brand-new developments during the period immediately after they move in. This can be avoided by including results from the Not Yet Built database in a postcode lookup integration.

A well-designed integration handles a "no results" response gracefully, for example, by falling back to a manual address entry field rather than blocking the user. If your customer base includes a significant proportion of people in newly built properties, it's worth asking API providers how they handle this scenario, and checking the docs for ease of adding the Not Yet Built database to the results.