OpenMeter is a real-time metering and billing engine that
helps you track usage, enforce limits, manage subscriptions,
and automate invoicing — all in one platform. Ingest events
via a simple API, define meters with flexible aggregations,
and connect usage data to billing, entitlements, and
customer-facing dashboards.

Features

• Usage Metering — Ingest events in

CloudEvents format, define meters
with flexible aggregations (SUM, COUNT, AVG, MIN, MAX),
and query usage in real time.

• Usage-Based Billing — Generate invoices from metered

usage. Supports tiered, graduated, and flat-fee pricing
with automated invoice lifecycle management.

• Usage Limits and Entitlements — Enforce usage quotas

per feature with real-time balance tracking, boolean
feature flags, and grace periods.

• Product Catalog — Define plans, add-ons, features, and

rate cards. Manage subscriptions with mid-cycle changes,
prorating, and alignment.

• Prepaid Credits — Support paid or promotional credit grants

with priority-based burn-down and expiration.

• Customer Portal — Token-based self-service dashboards

so your customers can see their own usage.

• Notifications — Webhook-based alerts with configurable

rules and channels for usage thresholds and billing events.

• LLM Cost Tracking — First-class support for metering

AI token usage and computing model-specific costs.

Getting Started

Cloud

The fastest way to start.
Start for free
and begin metering and billing in minutes —
no infrastructure to manage.

Self-Hosted

Run OpenMeter locally with Docker Compose:

git clone git@github.com:openmeterio/openmeter.git
cd openmeter/quickstart
docker compose up -d

Then ingest your first event:

curl -X POST http://localhost:48888/api/v1/events 
  -H 'Content-Type: application/cloudevents+json' 
  --data-raw '{
    "specversion": "1.0",
    "type": "request",
    "id": "00001",
    "time": "2026-07-07T00:00:00.001Z",
    "source": "my-service",
    "subject": "customer-1",
    "data": { "method": "GET", "route": "/api/hello" }
  }'

Query your usage:

curl 'http://localhost:48888/api/v1/meters/api_requests_total/query?windowSize=HOUR' | jq

See the full quickstart guide for more details.

Deploy to Production

Deploy to Kubernetes using our
Helm chart.

SDKs

| Language | Package | Source |
|----------------------|--------------------------------------------------------------------------------|----------------------------------------------------|
| Go | openmeter | api/client/go |
| JavaScript / Node.js | @openmeter/sdk | api/client/javascript |
| Python | openmeter | api/client/python |

Don't see your language? Use the
OpenAPI spec
directly or
request an SDK.

Architecture

OpenMeter is built in Go with a stack optimized for
high-volume event ingestion and real-time aggregation:

| Component | Role |
|--------------------------|----------------------------------------------------------|
| PostgreSQL (Ent ORM) | Billing, subscriptions, entitlements, product catalog |
| ClickHouse | Real-time usage aggregation and analytics |
| Kafka | Event streaming and ingestion pipeline |
| TypeSpec | API-first design — OpenAPI spec and SDKs from TypeSpec |

See Architecture and data flow for a
diagram of the runtime components and their primary interactions.

Community

We'd love to have you involved:

• Contributing — Start here if you

want to contribute code.

• Code of Conduct — Our community

guidelines.

• Blog — Product updates

and engineering deep dives.

Development

Prerequisites: Nix and
direnv are
recommended. See CONTRIBUTING.md for
detailed setup instructions.

make up       # Start dependencies (Postgres, Kafka, ClickHouse)
make server   # Run the API server with hot reload
make test     # Run tests
make lint     # Run linters

License

Licensed under Apache 2.0.