Is vertex API free?

Excuse me, I was wondering if I could inquire about the pricing model for the Vertex API. Specifically, I'm interested in knowing whether the Vertex API is offered as a free service or if there are any associated costs. I understand that APIs can often have various pricing tiers, so I'm keen to get a clear understanding of what the Vertex API entails in terms of financial commitment. Could you please provide me with some clarity on this matter?