The problem
The first AI invoice is a novelty. The twentieth is a crisis. By the time an enterprise has four pilot teams, three production workloads, and a sales org quietly using ChatGPT through a shadow subscription, the monthly spend is six figures and nobody can answer the simplest question: which team spent how much on what feature.
Procurement escalates to finance. Finance escalates to the CIO. The CIO asks engineering for a breakdown. Engineering has provider dashboards, not cost allocation. Everyone loses a week.
Why the usual approach breaks
Provider dashboards show you spend per API key. That is not per team. That is not per feature. One API key serves five internal apps. One internal app calls three providers. The billing data exists, the attribution does not.
Teams try to solve it with naming conventions on API keys. Naming conventions decay the moment someone rotates a key. The sprawl wins.
How AI Gateway closes the gap
AI Gateway enforces structured metadata on every model call: team, application, feature, environment. These are not optional headers the application forgets to set. They are gateway-enforced dimensions, tied to the authentication token the application uses to call the gateway. No metadata, no call.
Every token consumed carries attribution. The gateway writes a row per call into a cost ledger with team, app, feature, provider, model, tokens in, tokens out, computed cost at current provider rates, and policy applied. Procurement queries the ledger directly. Finance closes the month in a day, not a week.
Implementation pattern
The platform team onboards each application as a tenant with a per-tenant budget, a per-tenant rate limit, and per-tenant allowed-model list. Budgets refresh monthly. Rate limits protect shared provider quotas from one team's bad batch job. Allowed-model lists prevent a prototype team from silently migrating to the newest, most expensive model mid-quarter without procurement review.
When a team hits 80% of its budget, the gateway sends a warning event. At 100%, it returns a structured "budget exceeded" error. The application degrades gracefully, the finance team is not surprised, and the CIO does not learn about the overage from an invoice.
Next step
An architecture review maps your current AI spend against the tenant model and produces a per-team, per-feature baseline you can act on. Ninety minutes with you, one week to the written output.
Next step
Map Gateway against your stack in 90 minutes.