Meter every token. Attribute every cost.

Open-source usage metering for AI gateways and multi-tenant products — customer-level tokens and cost, without a full billing suite.

Run locally with make demo View on GitHub

Apache 2.0 · HTTP Custody · Python SDK · OpenAPI · Architecture

Usage event POST /ingest

{
  "customerId": "acme",
  "modelId": "gpt-4o-mini",
  "inputTokens": 1200,
  "outputTokens": 400
}

raw event

Customer usage line usage line

{
  "customer_id": "acme",
  "period": "2026-08",
  "input_tokens": 1200,
  "output_tokens": 400,
  "tokens": 1600,
  "cost_usd": "0.00042"
}

customer ledger

Verified camelCase ingest and snake_case usage fields. Not a live backend. Example cost uses gpt-4o-mini catalog rates from engine config/pricing.json (input $0.15/MTok, output $0.60/MTok).

quick start

bash

git clone \
  https://github.com/10kshuaizhang/fluxmeter.git
cd fluxmeter
make demo

Primary wedge

Built for AI gateways and token resellers.

One upstream AI account often serves many downstream customers. Provider totals are not customer-level billable usage.

Upstream provider totals

provider invoice · one pool

Customer-level billable usage

acme · 1600 tok · $0.00042

Illustrative use cases

From model response to usage line.

Core metering first. Control and export stay optional.

Ingest

SDK or Gateway via HTTP Custody.
Price

Model-specific input/output token rates.
Attribute

By customer, period, model, or span.
Control (optional)

Check, reserve, reconcile.
Export (optional)

Usage lines to billing or warehouse.
customer-level usage record

One path: HTTP Custody.

SDK/Gateway → HTTP Custody → Kafka ack → Flink billing/aggregation → Redis query → Usage API.

Supported path

SDK / Gateway

HTTP Custody

Kafka

Flink

Redis

Usage API

make demo starts the only supported full stack. ClickHouse is an audit cold store — not billing truth.

make demo = supported stack
Gateway: estimate → gate → reserve → upstream → Custody
Intelligence stays heuristic / secondary

Engine 4.4.1. Python/JS SDK 2.0.0 are repository versions — package-index publication not reverified.

Run customer-level usage locally.

Run make demo for the supported stack. Query usage from Redis via the Usage API.

Jump to quick start View source

Demo compose may leave authentication optional — enable API keys before any public or shared exposure.

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