Per-Branch AI Cost Tracking: How Neon Isolates Spend Across Dev Environments

Shared API gateway credentials across production, preview, and CI environments make it impossible to attribute AI model costs to specific deployments, often leaving teams unaware of runaway spend until a monthly invoice arrives. Neon's branching model addresses this by giving each branch its own deployment endpoint and its own Postgres database, meaning usage logs are isolated per environment. Because Neon uses copy-on-write branching, a new branch inherits a snapshot of the production ledger at creation time, but all subsequent spend is recorded only to that branch's own log. A developer tested this by running model calls on a CI branch and confirming that production's usage ledger remained unchanged. The approach relies on self-recorded usage logs within each branch's database rather than any native per-branch metering by the AI gateway provider itself.