[GCP Billing & Vertex AI] Solving Gemini Cost Allocation in a Single Project: Vertex AI Dynamic Billing Labels in Action

Pain Point: How to Accurately Allocate Gemini API Costs Within the Same Project?

When developing enterprise-level LLM services or operating multi-tenant platforms, the question most frequently asked by finance and operations teams is:

"We have many different business lines and LINE Bots connected within the same GCP project. Every day, the Gemini Key costs all appear under the Gemini API category. Is there a way for us to split the costs based on different Gemini Keys or different users?"

Direct answer to your question: In Google Cloud Billing reports, it is not possible to directly display costs "based on different API Key names." The smallest attribution dimensions for Google Cloud billing reports are "Project," "Service," and "SKU (Product Line Item)." The system does not treat individual API Key strings as independent billing items. For the billing system, whether you create 10 or 100 API Keys within the same project, they will all be lumped together as a single Gemini API total.

A Workaround: Vertex AI "Request Labels" to the Rescue