[veonik]

To add to the confusion, you can also just use Gemini via API (without Vertex AI). It shows up as a separate item in billing.

In the (latest, of three different) Go SDK, you can use either Vertex AI or Gemini. But not all features exist in either. Gemini can use uploaded files as attachments, and Vertex AI can use RAG stores, for example. Gemini uses API key based authentication, while Vertex AI uses the traditional credentials. All in the same SDK.

It's a mess.