Ingest usage events

Send usage events for billing. Accepts a single event or a batch of up to 1000 events. **Single event:** Send the event object directly in the request body. **Batch:** Wrap events in an `events` array. Events are matched to meters by `name` (event name) or `meter_id`. At least one of `customer_id`, `external_customer_id`, or `subscription_id` is required. **Idempotency:** provide `idempotency_key` per event. The key is unique per merchant forever; repeats return `duplicate` and do not create another billable event. **Attribution:** prefer `external_customer_id` when your system owns customer identifiers. Unknown external IDs fail fast instead of creating orphan usage. **Currency:** each subscription has one currency. Usage attributed to that subscription is interpreted in that currency; RevKeen does not perform FX conversion in the metering layer. --- **Related endpoints** - `GET /usage-events` — Query usage events - `POST /usage-events/dry-run` — Dry-run usage events - `GET /usage-events/aggregate/{meterId}` — Get aggregated usage **Common errors** - `400 invalid_request` — malformed payload or failed validation. - `401 authentication_error` — missing, invalid, expired, or revoked credential. Codes: `authentication_failed`, `invalid_api_key`, `expired_api_key`, `api_key_revoked`, `session_invalid`, `merchant_required`. Carries a `WWW-Authenticate: Bearer` challenge. **Idempotency** Pass an `Idempotency-Key` header (UUID v4 recommended) to make retries safe. Keys are valid for 24 hours; see [the idempotency guide](/docs/fundamentals/idempotency).

curl -X POST "https://api.revkeen.com/v2/usage-events" \
  -H "x-api-key: $REVKEEN_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "api_call",
    "customer_id": "string",
    "external_customer_id": "usr_123",
    "subscription_id": "string",
    "meter_id": "string",
    "quantity": 1,
    "timestamp": "2026-03-14T10:30:00Z",
    "idempotency_key": "evt_unique_123",
    "metadata": {}
  }'

{  "object": "usage_event_batch_result",  "summary": {    "ingested": 0,    "duplicate": 0,    "skipped": 0,    "failed": 0  },  "data": [    {      "index": 0,      "status": "ingested",      "id": "string",      "reason": "string"    }  ]}