Product Update: Idempotent Requests & US ZIP Lookups

Guarantee Idempotency and Prevent Duplicate Requests

When creating postcards, letters, or checks, can now pass an optional Idempotency-Key header. In the case of requests failing due to network errors, you can now safely retry these requests and guarantee that no duplicate mailings will be created and sent out.

Check out the API documentation or our implementation guide to learn more.

US ZIP Lookups API

In addition to providing a CASS Certified Address Verification API, we’ve also launch a US ZIP Lookups API! This allows you to pass in a US ZIP Code and get back a list of valid city and states associated with that ZIP Code.

Use this feature in forms to streamline the user checkout process, or turn a numeric ZIP Code into a more human-readable format.

Try out a few ZIP Codes on our free demo, or check out our API documentation.


As always, please reach out to us with any comments, questions, or feedback you may have. We love hearing from you and are always improving our offerings based on your thoughts!