@nestarc/outbox

Transactional outbox module for NestJS — emit domain events atomically within Prisma transactions, then reliably deliver them via polling, retry, and pluggable transports.

Features

• Prisma-native — events are stored in the same $transaction as your business data, eliminating dual-write failures
• Polling with FOR UPDATE SKIP LOCKED — multiple replicas poll concurrently without processing the same event twice
• @OnOutboxEvent() decorator — subscribe to events with a one-line decorator
• Type-safe events — extend OutboxEvent abstract class with static readonly eventType for compile-time safety
• Retry with backoff — fixed or exponential backoff strategy with configurable initial delay and max retries
• Stuck event recovery — events stuck in PROCESSING longer than stuckThreshold are automatically reset to PENDING
• Pluggable transports — LocalTransport for in-process dispatch, or custom adapters (Kafka, RabbitMQ, SQS)
• Batch polling — configurable batchSize to balance throughput and latency
• Graceful shutdown — poller drains in-flight events before the process exits
• Multi-tenant ready — tenant_id column included for future @nestarc/tenancy integration
• Raw SQL migration — no Prisma model needed; ships a ready-to-run SQL file

Requirements

• NestJS 10 or 11
• Prisma 5 or 6
• PostgreSQL 9.5+ (for SKIP LOCKED support)
• @nestjs/schedule (peer dependency)