Overview:
OpenMeter is an open-source real-time metering and billing engine designed for AI, agentic, and DevTool monetization. It helps developers track usage, enforce limits, manage subscriptions, and automate invoicing through a single platform. The system ingests usage events via a simple API, allows users to define meters with flexible aggregations like SUM, COUNT, and AVG, and connects this data to billing, entitlements, and customer-facing dashboards. It is built in Go and optimized for high-volume event ingestion.
Core Features:
Usage Metering: Ingest events in CloudEvents format and define meters with flexible aggregations (SUM, COUNT, AVG, MIN, MAX) to query usage in real time.
Usage-Based Billing: Generate invoices from metered usage with support for tiered, graduated, and flat-fee pricing, including 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, and 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: Provide token-based self-service dashboards so end customers can view their own usage.
Use Cases:
Developers building AI or agent-based products: Monitor and bill for token usage and model-specific costs using built-in LLM cost tracking.
SaaS teams implementing usage-based pricing: Define product plans, manage subscriptions with mid-cycle changes, and generate invoices from metered data.
Platform operators enforcing feature limits: Set usage quotas and real-time balance tracking per feature for customer entitlements.
Product teams offering customer self-service: Deploy token-based dashboards that allow customers to track their own usage independently.
Why It Matters:
OpenMeter provides a modular, self-hosted alternative to proprietary metering and billing services. Its architecture uses PostgreSQL, ClickHouse, and Kafka to handle high-volume event ingestion and real-time aggregation. The project includes official SDKs for Go, JavaScript/Node.js, and Python, and generates an OpenAPI spec from TypeSpec for language-agnostic integration. It directly addresses AI token metering and usage-based billing scenarios without requiring a third-party SaaS platform for monetization infrastructure.
