Yes, ShipTime does have a developer API. ShipTime recommends working with a developer to integrate the API.
The Development sandbox documentation for the REST API can be found here: https://sandboxapi.shiptime.com/
(Note: all endpoints begin with /rest)
Our REST API uses basic authentication.
Please contact firstname.lastname@example.org to request development environment credentials.
When you are ready for the Production environment, the URL is https://restapi.shiptime.com/ (Note: all endpoints begin with /rest)
Your ShipTime account credentials will be used for the Production environment.