iPaaS, API-led and event-driven integration compared: how to connect SaaS, ERP and CRM without a tangle and how to choose a platform.
The average organisation runs many SaaS applications alongside ERP, CRM and HR systems. Without a deliberate integration approach, point-to-point connections multiply into a fragile tangle that is hard to change.
Integration approaches
- Point-to-point: quick for one connection, but becomes unmanageable at scale.
- Integration platform as a service (iPaaS): cloud platforms with pre-built connectors, mapping and monitoring.
- API-led connectivity: reusable APIs that expose systems and processes in layers.
- Event-driven integration: systems publish events that others subscribe to, reducing tight coupling.
Choosing a platform
- Coverage of connectors for your key applications.
- Support for APIs, events, batch and file-based integration.
- Monitoring, error handling and retry capabilities.
- Security, governance and data residency options.
- Usability for both developers and trained business users.
Good practice
- Design reusable APIs rather than one-off connections.
- Keep a catalogue of integrations with owners and documentation.
- Monitor integrations and alert on failures before users notice.
- Agree data ownership so systems do not overwrite each other.
5 best practices for enterprise integration
- Build reusable APIs. Expose core data such as customers, products and orders through well-documented APIs that many applications can reuse.
- Use events for real-time updates. Publish business events, such as order created or employee hired, so subscribing systems react without constant polling.
- Centralise monitoring. Track message volumes, failures and latency in one place and alert integration owners when flows break.
- Apply security consistently. Use managed credentials, encryption in transit, least-privilege access and audit logs for every connection.
- Govern with a catalogue. Register every integration, API and owner so teams can discover existing assets instead of building duplicates.
How to choose an iPaaS
- Breadth and quality of prebuilt connectors for your key applications.
- Support for APIs, events, batch and file-based integration.
- Developer experience, including version control and testing.
- Scalability, regional hosting and compliance certifications.
- Pricing model based on connections, messages or capacity.
Common mistakes to avoid
- Recreating point-to-point spaghetti inside an iPaaS.
- Putting complex business logic in integration flows that are hard to test.
- Ignoring error handling and retries for failed messages.
- Letting integrations run under personal user accounts.
Frequently asked questions
What is the difference between iPaaS and an ESB?
An enterprise service bus is usually deployed on-premises and managed in-house. iPaaS is a cloud service that provides similar capabilities with less infrastructure overhead.
Can business users build integrations?
Many platforms offer low-code tools for simple flows, but critical integrations should follow IT governance.
A 90-day action plan
Days 1 to 30: map existing point-to-point connections, file transfers and scripts, and identify the integrations that fail most often or block new projects.
Days 31 to 60: select a platform, define naming, error-handling and security standards, and rebuild two high-value integrations using reusable interfaces.
Days 61 to 90: set up central monitoring and a catalogue, train developers and publish a roadmap for retiring fragile legacy connections.
Questions to ask vendors
- Which connectors are included, and how are they maintained when applications change?
- Can integrations run in our own network for on-premises systems?
- How are deployments promoted from development to production?
- What monitoring, alerting and replay capabilities are available?
- How does pricing change as message volumes grow?
Key terms explained
- API-led connectivity: organising interfaces into system, process and experience layers.
- Event-driven architecture: systems communicating by publishing and subscribing to events.
- Point-to-point integration: a direct connection between two systems.
- Dead letter queue: a holding area for messages that could not be processed.
The bottom line
As organisations adopt more SaaS applications, the way systems connect becomes a strategic capability. Reusable interfaces, event-driven patterns, strong security and central monitoring turn integration from a source of fragility into an enabler of new projects. Choose a platform that fits your applications and skills, set standards early and maintain a catalogue so teams reuse what already exists. Over time, a well-governed integration layer speeds delivery and makes changing individual applications far easier.
Further reading on iPaaS
For authoritative, vendor-neutral guidance on iPaaS, see the OpenAPI Initiative. You can also browse our free whitepapers.
