We strongly prefer audience files via SFTP.
We will also accept audience files through S3 and Alli Data. Non-PII data can be imported using the Alli SFTP connector.
Google AdWords API
Google Customer Match Uploader (CMU) API
Other - If the 3rd party accepts SFTP audience drops we can send CRM lists containing hashed email addresses only. For example, we have done this with the following partners: