B2B Ecommerce Integration Patterns: Point-to-Point vs iPaaS vs Middleware (How to Choose)

Should you connect your ERP directly to your ecommerce platform? Use an integration platform? Build custom middleware? Here's how to evaluate the tradeoffs for B2B commerce—with a decision framework you can use today.

February 6, 2026

You need to connect your ERP to your ecommerce platform. Simple, right?

Except nothing about B2B integration is simple. You have customer-specific pricing. Complex inventory allocation. Multi-warehouse fulfillment. Order orchestration that involves three systems before a package ships.

And the method you choose for integration—point-to-point, iPaaS, or custom middleware—will determine whether you spend the next five years maintaining a stable system or firefighting a brittle mess.

This guide walks through the three major integration patterns, when each makes sense, and how to evaluate them for your specific situation.

The Three Integration Patterns

Pattern 1: Point-to-Point Integration

What it is: Direct connections between pairs of systems. ERP talks to ecommerce. Ecommerce talks to OMS. Each connection is its own integration.

How it works: You configure connectors (usually vendor-provided) or build custom integrations for each pair. Data flows directly from source to destination.

Example: Adobe Commerce’s Magento-Epicor connector, or a custom API integration between your WMS and your ecommerce platform.

Pros:

• Fastest to implement for simple scenarios
• No additional platform to license
• Direct control over data transformation
• Often the cheapest starting point

Cons:

• Scales poorly (n systems = n(n-1)/2 potential connections)
• No central visibility into integration health
• Changes in one system may break multiple integrations
• Duplication of logic across connections

Best for: Small operations (2-3 systems), simple data flows, limited budget, or when vendor-provided connectors exist and work well.

Pattern 2: iPaaS (Integration Platform as a Service)

What it is: A cloud platform that manages integrations between systems. You connect each system to the iPaaS, and it handles data routing, transformation, and orchestration.

Platforms: Celigo, Boomi, Workato, MuleSoft Anypoint, Jitterbit, Tray.io.

How it works: Each system connects to the iPaaS via connector or API. You configure flows visually (or via code). The platform handles scheduling, error handling, and monitoring.

Pros:

• Central visibility—one dashboard for all integrations
• Pre-built connectors for common systems
• Often includes monitoring, alerting, and retry logic
• Easier to add new integrations over time
• Less custom code to maintain

Cons:

• Per-transaction or per-connection pricing can scale quickly
• You’re dependent on the platform (vendor risk)
• Complex transformations may still require custom code
• Performance overhead for high-volume, real-time scenarios

Best for: Growing operations (4+ systems), standard integration patterns, teams without deep integration engineering capacity, when you value operational visibility.

Pattern 3: Custom Middleware

What it is: A purpose-built integration layer (often microservices or a message-based architecture) that sits between your systems. You build and maintain it.

Technologies: Node.js/Python services, message queues (RabbitMQ, AWS SQS, Kafka), API gateways.

How it works: Each system connects to the middleware layer. The middleware handles translation, routing, orchestration, and business logic. Often event-driven.

Pros:

• Full control over architecture and logic
• Can handle complex, non-standard scenarios
• No per-transaction licensing fees
• Can optimize for performance when needed
• Becomes a competitive advantage if done well

Cons:

• Highest upfront investment (design + development)
• Requires ongoing maintenance and DevOps capacity
• Easy to over-engineer for simple scenarios
• Failure modes are your responsibility to handle

Best for: Large or complex operations, non-standard integration requirements, high transaction volumes, organizations with strong engineering capacity, when integration is a strategic differentiator.

Decision Framework: How to Choose

1. Count Your Systems

How many systems need to integrate?

• 2-3 systems: Point-to-point is probably fine. The overhead of iPaaS isn’t worth it.
• 4-7 systems: iPaaS starts to pay off. Central management becomes valuable.
• 8+ systems: iPaaS or middleware. Point-to-point becomes unmaintainable.

2. Assess Your Data Flow Complexity

Are your integrations simple CRUD sync (create/read/update/delete)? Or do they involve business logic?

Simple flows (product sync, order transmission, inventory updates with no allocation logic): Point-to-point or iPaaS.

Complex flows (multi-warehouse allocation, customer-specific pricing rules, backorder splitting, payment routing): iPaaS with custom logic or middleware.

Highly custom logic (vendor-specific EDI requirements, industry-specific protocols, real-time pricing calculations): Middleware.

3. Evaluate Your Volume and Latency Requirements

How much data flows, and how fast does it need to move?

Low volume, batch is fine (< 10,000 orders/month, hourly inventory updates acceptable): Any pattern works.

Medium volume, near-real-time desired (10,000-100,000 orders/month, <15 min latency for inventory): iPaaS handles this well.

High volume, real-time required (100,000+ orders/month, sub-second inventory updates): Custom middleware, possibly with message streaming.

iPaaS platforms charge by transaction. High-volume scenarios can become expensive quickly. Do the math.

4. Consider Your Team

Who maintains this?

No dedicated integration engineers: Point-to-point with vendor connectors, or iPaaS with good support.

Some technical capacity but not deep integration experience: iPaaS. The platform handles the hard parts.

Strong engineering team: Any option is viable. Middleware becomes more attractive if you have capacity.

5. Project Forward 3-5 Years

What will your system landscape look like in 2028?

If you’re adding systems, channels, or complexity, choose an architecture that scales. Point-to-point today becomes unmaintainable in two years. Middleware you build today becomes an asset.

Hybrid Patterns

You don’t have to choose just one.

iPaaS + point-to-point: Use iPaaS for most integrations, but keep a point-to-point connector for a simple, high-volume sync that would be expensive to run through the platform.

iPaaS + custom middleware: Use iPaaS for standard flows, but route complex scenarios through custom middleware for business logic.

Middleware + managed connectors: Build your own orchestration layer, but use pre-built connectors to systems instead of coding API integrations from scratch.

Common Mistakes

Mistake 1: Starting with Middleware When iPaaS Would Work

Middleware is appealing to engineering teams. It’s “the right way” to build systems. But it’s expensive to build and maintain. If an iPaaS platform can handle your requirements for the next 3 years, that’s the pragmatic choice.

Mistake 2: Outgrowing Point-to-Point Without Noticing

You started with two systems. Now you have seven. Each one has direct connections to three others. Nobody can trace data flows anymore. “It works” until it doesn’t, and then debugging is a nightmare.

Plan your migration to iPaaS or middleware before you’re in crisis.

Mistake 3: Choosing iPaaS Based on Connectors Alone

A platform having a “connector” for your ERP doesn’t mean it will work for your use case. Connectors often handle only basic scenarios. Complex B2B requirements (customer-specific pricing, complex allocation) may still need custom development within the iPaaS.

Evaluate connectors for your specific flows, not just existence.

Mistake 4: Underestimating iPaaS Costs at Scale

iPaaS pricing models vary: per connection, per flow, per transaction, per monthly active record. Get quotes based on your actual volume, not entry-tier assumptions.

A platform that costs $2,000/month for basic use may cost $20,000/month at your transaction volume.

Mistake 5: Building Middleware for Simple Problems

If your requirement is “sync products from PIM to ecommerce nightly,” you don’t need Kafka. You need a scheduled job and an API call. Don’t over-engineer.

Integration Pattern by Scenario

Making the Call

Here’s the short version:

Start with point-to-point if you have 2-3 systems, simple flows, and a working vendor connector.

Choose iPaaS when you have 4+ systems, want central visibility, don’t have deep integration engineering capacity, and your volumes are within platform pricing reasonability.

Build middleware when you have complex logic, high volumes, non-standard requirements, engineering capacity, or when integration is a competitive advantage.

And reassess every 18-24 months. What worked when you were smaller may not work at scale.

Not sure which pattern fits? We’ve designed integration architectures for B2B distributors and manufacturers across all three patterns. Schedule a discovery call—we’ll review your system landscape, map your data flows, and recommend the right approach for your situation.