When submitting a customer via the POST /participants/customers/new endpoint, the Zero Hash API has the following validation logic on the zip field:
- Can either be 5 numbers (standard format) or 5 numbers, a hyphen, followed by 4 more numbers (Zip+4). Examples:
- Standard: 12345
- Zip+4: 12345-6789
- Avoid trailing whitespace, ie you should submit "12345" and not "12345 "