Tandem core — models, ports, exceptions and pure logic (zero runtime dependencies)

Tandem JDBC adapter — write-side insert and the relay engine (PostgreSQL baseline)

Tandem CloudEvents envelope: OutboxRecord to CloudEvent, independent of the transport that carries it

Tandem Kafka adapter — OutboxDispatcher over the Kafka producer (CloudEvents binary binding)

Tandem Micrometer adapter — TandemMetrics backed by a Micrometer MeterRegistry

Tandem RabbitMQ connector — OutboxDispatcher over AMQP 0.9.1 (CloudEvents binary binding)

Tandem test support — in-memory collaborators and the Testcontainers helper

Tandem OpenTelemetry adapter — trace capture and relay publish spans without Spring