AddressZen vs PostNL Address Validation API

AddressZen provides address lookup, autocomplete, validation, and verification for US and international addresses through an API, browser extension, and web interface. Its validation can normalize formatting, expand street and city abbreviations, add missing ZIP+4 details, and correct typos. It advertises coverage in 240+ countries and support for 60+ languages, with local address data that includes USPS sources for US verification and details such as apartment and suite numbers. Suggestions are real-time and matching accounts for typos. Developers can use JavaScript libraries, a React component, or a REST API; listed integrations include Zapier, Adobe Commerce, WooCommerce, and form tools. Batch validation and API key controls are available, including lookup limits, allowed URLs, and configurable transaction-log retention. The free plan includes 1,400 verified addresses for one year. The Address bundle is $1,000, paid once for 55,000 verified addresses. Billing is per verified address, with no setup fees or monthly commitment. The API reference limits each IP to 30 requests per second, with a separate autocomplete limit.

PostNL Address Validation API checks address data entered in a webshop or CRM for Netherlands and international destinations. As customers type a few letters or numbers, it can suggest matching addresses. Documentation describes coverage across more than 250 countries, regions, and island groups. Responses may include a locally formatted address, component fields, mailability and similarity scores, and latitude and longitude. The service supports correction, standardization, and autocomplete. Its international v3 endpoint uses POST and requires an API key with application/json content. CountryIso is mandatory; city, postal code, street, and house number are recommended inputs. PostNL lists plugins for Magento, WooCommerce, ShopWare, and Opencart for Dutch validation. The Benelux plan is free for PostNL parcel-contract customers and requires that contract. International validation starts at €0.02, paid once per API call, with bundle pricing varying by address volume. Returning multiple addresses in one response is temporarily unavailable. PostNL offers demos and data-solutions support.