what is SandboxURL for API version 2.1 ?

[Anonymous]

What is SandboxURL for API version 2.1 that will work for all Marketo Sandbox Accounts for user input parameters – ie. UserID, HostName and EncryptionKey.

[Anonymous]

The URL for API version 2.1 can be found at Admin - SOAP API

It is displayed as "SOAP endpoint".

In the past the endpoint was generic for a cluster.
The Munchkin ID, unique for each instance, has been added to recent releases.
That is an important security enhancement.

The endpoint for a theorethical Munchkin ID ABC-123-000 would be
https://ABC-123-000.mktoapi.com/soap/mktows/2_1
The WSDL can be found at
https://ABC-123-000.mktoapi.com/soap/mktows/2_1?WSDL

Please kee in mind the Munchkin ID is distinct for each instance no matter it is sandbox or production.