1. Smarty
High-speed address validation and US ZIP code lookup APIs.
Smarty offers high-performance cloud APIs that standardize US addresses, return ZIP+4 additions, and provide postal centroid coordinates. It automatically verifies delivery points against official USPS data. Developers, e-commerce platforms, and logistics teams use Smarty to eliminate shipping errors and validate customer checkout data at scale.
Pros
- Extremely low latency API responses suitable for live checkout forms
- Official CASS-certified address verification and ZIP+4 appending
- Includes county name, FIPS code, and timezone data in responses
Cons
- Tiered API plans can become expensive at enterprise query scales
- Does not offer advanced geographic polygon boundary mapping natively
