Dominant scenario
AI gateways
Upstream problem
One upstream provider account serves many downstream callers. Provider invoices show a single pool — not who consumed which tokens.
Event boundary
Meter at the gateway edge after the model response (or via the FluxMeter gateway proxy hooks), with a stable eventId for dedup.
Customer attribution
customerId maps to the downstream tenant or API key owner; modelId and token fields come from the provider response.
Budget / control
Optional pre-request GET /budget/{id}/check (and reserve/reconcile for streams) before forwarding upstream.
Query customer usage via GET /usage/customer/{customer_id}/period/{period}, GET /usage/customer/{customer_id}/day/{date}, and GET /usage/customer/{customer_id}/model/{model_id} for dashboard or export lines.
Starting mode
Base stack
Evaluation and supported deploy use the same HTTP → Kafka → Flink path via make demo.