Postcoder
Allies Computing
£27 per 500 credits
Postcoder is a global address verification and customer data validation API used by over 10,000 organisations worldwide. Built by Allies Computing, Postcoder helps businesses capture clean, accurate customer data at the point of entry, reducing errors, cutting failed deliveries, and speeding up checkout and onboarding flows.
Postcoder's address lookup API lets users find verified addresses instantly using postcode lookup or address autocomplete. Look up addresses based on a postcode, part of an address or a coordinate position. Postcoder provides access to Royal Mail PAF and Multiple Residence addresses, Ordnance Survey AddressBase property records and international addresses in 249 countries.
Beyond address verification, Postcoder offers a full suite of contact data validation tools in a single API integration.
Bank account validation checks sort codes and account numbers in real time, confirming validity, returning branch details, and verifying direct debit eligibility - useful for subscription businesses, lenders, and anyone collecting payment mandates.
Email validation checks formatting, domain validity, and flags disposable or high-risk addresses to keep CRM data clean and improve deliverability.
Mobile number validation checks whether a number is active and connected across 200+ countries, helping reduce wasted SMS spend and improve contact rates.
For added security, Postcoder also offers OTP verification, delivering one-time passwords via SMS to protect customer accounts at sign-up, login, or checkout.
Developers appreciate the comprehensive documentation and sample code, and a 30-day free trial means teams can get up and running in minutes without a credit card.