Four Typical ERP Integration Patterns: Direct API, Staging Tables, Message Queues, and iPaaS

Pattern 1: Point-to-Point Direct API

System A calls the ERP's API directly, with nothing in between. It is the fastest to launch — short path, low latency, simple implementation. The cost is tight coupling: when the ERP upgrades its interface, every caller must follow, and as integrations multiply the dependency web becomes unmappable. Best for very few (three or fewer), stable, long-lived connections such as bank-enterprise direct links.

Pattern 2: Staging Database Tables

Both sides agree on a set of intermediate tables: one system writes, the ERP polls and writes back status. This is the most common "pragmatic" approach in domestic ERP implementations. It decouples database and API styles and makes reconciliation easy (the staging table is the ledger), but latency is bound by the polling interval, the tables bloat over years until nobody dares touch them, and direct database access brings security concerns. Best for batch, low-frequency flows like financial voucher sync.

Pattern 3: Message Queues

Systems exchange events through an MQ (Kafka, RabbitMQ, RocketMQ): an order-created event is published, the ERP consumes it and creates the bill, and the result is published back. MQ gives natural asynchronous decoupling and traffic shaping — promotion peaks don't crush the ERP — plus durable, replayable messages. The price is new infrastructure, ordering and duplicate-consumption design, dead-letter handling, and a higher bar for troubleshooting. Best for high-concurrency, event-driven transactional links.

Pattern 4: iPaaS

An integration platform sits in the middle of all data flows: connectors absorb endpoint differences, orchestration defines business flows, and the platform handles scheduling, retry, idempotency, and monitoring. You get a unified registry of all integrations, configuration-driven onboarding of new links, and out-of-the-box alerting and replay. The trade-off is platform dependency and unsuitability for extreme latency/throughput niches. Best for growing enterprises with many systems and constantly evolving integrations.

Decision Guide

Real architectures are almost always hybrids: MQ for core transaction flows, iPaaS or staging tables for master data and financial batches, direct links for a few stable connections. There is no silver bullet, but one shared test: every link must be able to answer "where does the data come from, where does it go, and what happens if it breaks?"