Our high level sandbox and production endpoints are listed below for clarity.

For the Secure Fields script:

Sandbox: https://pay.sandbox.datatrans.com/upp/payment/js/secure-fields-2.0.0.js
Minified version: https://pay.sandbox.datatrans.com/upp/payment/js/secure-fields-2.0.0.min.js

Production: https://pay.datatrans.com/upp/payment/js/secure-fields-2.0.0.js
Minified version: https://pay.datatrans.com/upp/payment/js/secure-fields-2.0.0.min.js

Check out the rest of the API reference in this section for details on the relevant paths, parameters and headers!