AddressZen vs UPU POST*CODE API
AddressZen
addresszen.comUPU POST*CODE API
upu.intSide by side
| Figure | AddressZen | UPU POST*CODE API |
|---|---|---|
| Price from | Free | — |
| Free plan | Yes | — |
| Free trial | Yes | Yes |
| Open source | — | — |
| Web | Yes | Yes |
| iOS | Yes | — |
| Android | Yes | — |
| API | Yes | Yes |
| Plans published | 7 | 1 |
| Spec score · Address Verification Software | 9.3 (#2) | 7.8 (#19) |
| Documentation | Documentation includes integration guides, API reference, SDK instructions, key management, testing, data coverage and changelog material. | The API documentation includes tutorials, quick-start guides, and developer tooling. |
| Founded | 2012 | 1874 |
| Integrations | Listed integrations include Zapier, Adobe Commerce, WooCommerce, Contact Form 7, Gravity Forms, Gutenberg, Ninja Forms, FormAssembly, Formidable Forms, Formstack, JetFormBuilder and Elementor Pro. | The API can be used as a CDS plugin, through the CDS API gateway or other middleware, or integrated into postal websites and local applications. |
| Security | AddressZen says its information security management system was recertified to ISO 27001 in 2025 and that its certification streak began in 2020. | The CDS setup guide describes a security token used to identify and authenticate a CDS installation, with tokens unique to countries. |
| Support | Support and live chat are advertised Monday through Friday, 9 AM to 5 PM Eastern Time. | The guide directs users with questions about costs, documentation, or a free trial to [email protected]. |
Plans
AddressZen
- FreeFree
- Free for 1 yearFree
- 1,400 verified addresses$49, paid once
- 5,000 verified addresses$149, paid once
- 14,000 verified addresses$349, paid once
- 55,000 verified addresses$1,000, paid once
- Address bundle$1,000, paid once
In their own words
AddressZen
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.
UPU POST*CODE API
UPU POST*CODE API verifies international addresses using official locality names and postcode data from UPU member countries. Its checks cover a country’s postcode format, whether a postcode matches a locality, postcodes associated with a locality, and localities associated with a postcode. LocalityLike suggests official locality names and postal regions from the beginning of a partial locality input. The API is intended for designated postal operators, businesses, and individuals handling international addresses, including customs declarations, web shops, user platforms, and ERP systems. It can run as a CDS plugin, through the CDS API gateway or other middleware, or inside postal websites and local applications. Development guidance covers HTML, web applications, JavaScript form handling, and sample code for jQuery and Python. Documentation includes tutorials, quick-start guides, and developer tooling. UPU says response time is under one second and performance can be adjusted to expected call volume. Pricing is on request, with a free trial available by contacting UPU.