Yes, PaidShipping does have a developer API. PaidShipping recommends working with a developer to integrate the API.
The API documentation for our REST API can be found here: https://restapi.paidshipping.com/
(Note: all endpoints begin with /rest)
Our REST API uses basic authentication.
Please contact firstname.lastname@example.org to request development environment credentials.
Your PaidShipping account credentials will be used for the Production environment.