openova/platform/openmeter

OpenMeter

Usage metering for OpenOva Open Banking blueprint.

Status: Accepted | Updated: 2026-01-17

---

Overview

OpenMeter provides real-time usage metering:

• CloudEvents-based ingestion
• ClickHouse backend for analytics
• Integration with Lago for billing
• Real-time usage dashboards

---

Architecture

flowchart TB
    subgraph Sources["Event Sources"]
        API[Open Banking API]
        Gateway[API Gateway]
    end

    subgraph OpenMeter["OpenMeter"]
        Ingest[Ingest API]
        Process[Event Processor]
        Query[Query API]
    end

    subgraph Storage["Storage"]
        Kafka[Redpanda]
        CH[ClickHouse]
    end

    subgraph Consumers["Consumers"]
        Lago[Lago Billing]
        Grafana[Grafana]
    end

    API --> Ingest
    Gateway --> Ingest
    Ingest --> Kafka
    Kafka --> Process
    Process --> CH
    Query --> CH
    Lago --> Query
    Grafana --> Query

---

Event Format (CloudEvents)

{
  "specversion": "1.0",
  "type": "api.call",
  "source": "open-banking-api",
  "id": "uuid-here",
  "time": "2024-01-15T10:30:00Z",
  "subject": "tpp-12345",
  "data": {
    "endpoint": "/accounts",
    "method": "GET",
    "status_code": 200,
    "response_time_ms": 45
  }
}

---

Configuration

OpenMeter Deployment

apiVersion: apps/v1
kind: Deployment
metadata:
  name: openmeter
  namespace: open-banking
spec:
  template:
    spec:
      containers:
        - name: openmeter
          image: openmeter/openmeter:v1.0.0
          env:
            - name: OPENMETER_KAFKA_BROKER
              value: redpanda.databases.svc:9092
            - name: OPENMETER_CLICKHOUSE_ADDRESS
              value: clickhouse.databases.svc:9000
            - name: OPENMETER_POSTGRES_URL
              valueFrom:
                secretKeyRef:
                  name: openmeter-db-credentials
                  key: url

Meter Definition

meters:
  - slug: api_calls
    description: API call count per TPP
    eventType: api.call
    aggregation: COUNT
    groupBy:
      subject: true
      endpoint: $.data.endpoint
      method: $.data.method

  - slug: api_latency
    description: API latency percentiles
    eventType: api.call
    valueProperty: $.data.response_time_ms
    aggregation: SUM
    groupBy:
      subject: true
      endpoint: $.data.endpoint

---

Integration with Lago

OpenMeter syncs usage to Lago for billing:

sequenceDiagram
    participant API as Open Banking API
    participant OM as OpenMeter
    participant CH as ClickHouse
    participant Lago as Lago

    API->>OM: Send CloudEvent
    OM->>CH: Store event
    Note over OM,Lago: Hourly sync
    OM->>OM: Aggregate usage
    OM->>Lago: Push usage records
    Lago->>Lago: Update customer balance

Sync Configuration

apiVersion: v1
kind: ConfigMap
metadata:
  name: openmeter-lago-sync
  namespace: open-banking
data:
  config.yaml: |
    lago:
      url: http://lago.open-banking.svc:3000
      api_key_secret: lago-api-key
      sync_interval: 1h
    meters:
      - slug: api_calls
        lago_billable_metric_code: api_calls    

---

Quota Checking (Real-Time)

For prepaid credits, Valkey provides real-time quota checks:

flowchart LR
    subgraph RealTime["Real-Time Path"]
        API[API Gateway]
        Valkey[Valkey]
    end

    subgraph Billing["Billing Path"]
        OM[OpenMeter]
        Lago[Lago]
    end

    API -->|"Check quota"| Valkey
    API -->|"Record event"| OM
    OM -->|"Sync usage"| Lago
    Lago -->|"Update credits"| Valkey

---

Monitoring

Metric	Description
openmeter_events_ingested_total	Total events ingested
openmeter_events_processed_total	Events processed
openmeter_query_latency_seconds	Query latency

---

Part of OpenOva