Ideal Postcodes

findAddress.io is a fast, reliable UK address lookup and postcode validation API built for developers and businesses that need accurate address data without enterprise-level complexity or cost. Our RESTful JSON API provides postcode lookup, address autocomplete and real-time address validation, helping improve form completion rates, reduce address errors and capture clean, structured UK address data at the point of entry. Designed for modern web applications, findAddress.io integrates easily into checkout flows, registration forms, CRMs and internal systems using JavaScript, PHP, Node.js and other common stacks.

Postcoder is an API from Allies Computing that gives developers a single endpoint for verifying and validating customer contact data at the point of entry. Used across sectors from healthcare to retail, it's built to drop into checkout, onboarding, and account creation flows with minimal friction. What's included: Address lookup – Postcode, partial address, or coordinate-based search across Royal Mail PAF, Ordnance Survey AddressBase, and 249 countries worldwide. Bank validation – Real-time sort code and account number verification, with branch data and direct debit eligibility returned in the response. Email validation – Domain and formatting checks with disposable address detection. Mobile validation – Live network status checks across 200+ countries. OTP verification – SMS-based one-time password delivery. Clear documentation, multi-language sample code, and a straightforward REST structure mean integration is quick. 30 day free trial with no credit card required.