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Midaz emits CloudEvents for ledger, CRM, Fees, and Tracer business facts. The current complete contract is the Kafka/lib-streaming surface. Legacy RabbitMQ exchanges carry only a narrower compatibility subset.

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Current event surface — Kafka

Enable publication on each producing service:
STREAMING_CLOUDEVENTS_SOURCE is required when streaming is enabled. Use ledger for the ledger, CRM, and Fees binary and tracer for Tracer; each service rejects any other value at startup. Midaz uses one v3 application fact topic per producing service:
  • Ledger, CRM, and Fees: lerian.streaming.ledger
  • Tracer: lerian.streaming.tracer
Examples:
  • organization.created rides lerian.streaming.ledger
  • transaction.posted rides lerian.streaming.ledger
  • fee_charge.applied rides lerian.streaming.ledger
  • rule.created rides lerian.streaming.tracer
The CloudEvents type is source-qualified: studio.lerian.<source>.<resource>.<event>. ce-resourcetype and ce-eventtype carry the dispatch key as separate headers. Payload schema is 1.0.0 for the current catalog. The ledger and Tracer each serve their exact catalog and topic mapping at:
The manifest route remains available even when publication is disabled. Use it as the deployment-time contract instead of guessing topics. The Midaz event reference and Tracer event reference list every event and payload.

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Delivery semantics

Midaz publishes these business events directly after the state change. It does not persist them in a streaming outbox, and publication failures are logged rather than returned to the business command. Consumers must still be idempotent and deduplicate on (ce-source, ce-id) because broker delivery can repeat a published record. Money values use decimal strings; never parse them as binary floating point.

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Consumer checklist

  1. Read the producer manifest.
  2. Subscribe to the producer’s application topic.
  3. Route on ce-resourcetype and ce-eventtype, not on payload shape.
  4. Validate ce-schemaversion before decoding.
  5. Persist your deduplication key before acknowledging the record.

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Legacy RabbitMQ surface

Midaz also maintains legacy RabbitMQ exchanges for selected transaction, overdraft, and audit events. This is not the complete lib-streaming catalog. The bundled example configuration ships these outbound exchanges disabled. If you enable them, you own queue bindings, ack/nack, dead-lettering, retries, and consumer isolation. The internal async transaction balance-operation pipeline controlled by RABBITMQ_TRANSACTION_ASYNC is not a public event feed. Use the Kafka surface for new integrations unless you explicitly depend on a legacy RabbitMQ contract.

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Streaming Hub compatibility

Streaming Hub follows the v3 Midaz application topics lerian.streaming.ledger and lerian.streaming.tracer. A subscription can therefore receive Midaz facts when the producer, hub ingest, and destination runtime are enabled. Match on the event key from ce-resourcetype and ce-eventtype; do not expect a per-event Kafka topic.

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Decision