iPaaS vs. ESB

DZone 's Guide to

iPaaS vs. ESB

The main difference between iPaaS and ESB lies in the kind of systems they integrate best, the level of complexity of their integrations, and their scalability.

· Integration Zone ·
Free Resource

According to an IDC report, investments in public cloud services are expected to grow to $203.4 billion globally, with a CAGR of 21.5%. The overwhelming rate at which enterprises are adopting cloud services is creating an integration challenge for enterprises using older on-premises integration systems such as ESBs whose systems weren’t designed to handle cloud integration.

As a response, enterprises are turning to integration tools and solutions such as Integration Platform as a Service (iPaaS) to supplement the weaknesses of their existing enterprise service bus (ESB) installations.

But what exactly are the differences between iPaaS and ESB? When should an enterprise use iPaaS? How about ESB? In this post, we shed some light on the differences between these two integration tools.

iPaaS vs. ESB: An Overview

iPaaS and ESB serve the same main purpose: the integration of enterprise systems and applications. The main difference between iPaaS and ESB lies in the kind of systems they integrate best, the level of complexity of their integrations, and their scalability.

System Type

Generally, iPaaS and ESB are on opposite ends of the continuum. iPaaS is a set of integration tools delivered from a public cloud and requires no on-premises hardware or software. iPaaS was specifically designed to handle the lightweight messaging and document standards (REST, JSON, etc.) used by today’s cloud apps.

ESB, on the other hand, is an on-premises software architecture model that typically utilizes technology common before the rise of the cloud. As such, its heavy on-premises footprint and older messaging and document standards work best for integrating on-premises and aggregated systems such as SAP.

However, these two integration models are seeing come convergence; some iPaaS solutions have evolved to support on-premises systems, while some ESB vendors have introduced features to more elegantly support the integration of cloud services.


ESB is designed to integrate complex IT systems and architecture. It holds together an enterprise’s on-premises and legacy systems. iPaaS, on the other hand, offers a more lightweight integration solution better suited for flexible and real-time applications, which are critical requirements of cloud-based services.


Finally, a major point of difference between iPaaS and ESB is the direction of scalability. ESB is best suited for vertical scalability — the integration of an enterprise’s complex internal systems and architecture. This makes sense when you consider the evolution of the ESB, which came of age more than a decade ago when enterprise resource planning (ERP) systems were the heavyweights of enterprise software. On the other hand, iPaaS is better suited for horizontal scalability — integration with third parties, partners, and ad hoc applications such as Software as a Service (SaaS) solutions. Lightweight and flexible, iPaaS enables enterprises to quickly connect and integrate their cloud applications and systems.

Going Deeper: Other Differences and Use Cases of iPaaS

Aside from these main differences, there are other factors that differentiate iPaas and ESB, such as multi-tenancy. Understanding the use cases for iPaaS can also help to further contrast the two technologies.

Multi-Tenant Architecture

A multi-tenant architecture refers to a single instance of software running on a single server while serving multiple groups of users. For example, a single software that caters to different individuals or departments such as finance, marketing, and operations operates on a multi-tenant architecture. Because of their inherent complexity, most ESB solutions are not multi-tenant.

On the other hand, iPaaS supports multi-tenancy. This gives iPaaS solutions an advantage over ESB as multiple tenants or users can share a single instance to effectively reduce redundancies in integration processes. Multi-tenancy can also reduce infrastructure and administrative costs during integration.

Ad Hoc Integration

Traditionally, software and application initiatives are carried out by an enterprise’s IT department. However, more and more departments today are being empowered to purchase, install, and utilize their own software on an ad hoc basis, especially now that SaaS solutions are making it possible for applications to fall under a department’s operating expenses instead of its capital expenditures. Ad hoc solutions require flexible, lightweight, and real-time integration.

ESB is too slow and complex for ad hoc integration projects. It requires the expertise of IT departments which defeats the purpose of ad hoc application initiatives and slows down project delivery. The simplicity, the flexibility, and the real-time capabilities of iPaaS solutions help meet the fast-paced demands of ad hoc integrations and aid other auxiliary departments to efficiently achieve their business goals without being held back by the complexity of ESB.

SaaS Integration

Today, both iPaaS and ESB can integrate SaaS solutions with on-premises and legacy systems. iPaaS inherently uses lightweight connectors such as JSON and API which are best suited for SaaS integration, while there are a growing number of ESB solutions that can utilize the same lightweight web service protocols. Experts call these integration technologies lightweight ESBs or cloud ESBs. However, traditional ESB uses more complex middleware technologies such as Message-Oriented Middleware (MOM) architecture which is not utilized by SaaS solutions.

IoT Integration

In addition to SaaS, another emerging trend is the rise of internet-enabled devices or the Internet of Things (IoT). IoT integration requires significantly high horizontal scalability due to the sheer volume of connected devices, lightweight connectivity, and the low latency required for optimal performance. Aside from these requirements, IoT integration also demands real-time connection. These factors make ESB poorly suited for this kind of integration. Furthermore, IoT integration also requires external integration. Putting all these factors together, it is easy to conclude that the better integration solution for IoT is iPaaS.

Complementing, Not Competing Technologies

Despite its seemingly overwhelming advantages over ESB, iPaaS still has its limitations. It is still not practical and cost efficient to utilize iPaaS for enterprises with complex organizational systems and internal architectures. ESB is still the preferred glue for holding internal systems together. For this reason, iPaaS and ESB are often utilized by enterprises at the same time to hold their internal architecture and legacy systems together, while still accommodating new integration end points such as SaaS, cloud services, and IoT devices.

A More Powerful Integration Solution

The Liaison ALLOY™ Platform represents the best of both the ESB and iPaaS worlds. Like iPaaS, Liaison ALLOY is a multi-tenant cloud integration platform that helps enterprises integrate ever-growing numbers of cloud applications and data sources. Like ESB, ALLOY also handles complex integrations among on-premises applications. In addition, ALLOY supports integration between on-premises and cloud applications (often referred to as hybrid integration). ALLOY delivers all this through a managed services approach to integration, which frees enterprises to focus their IT resources on more strategic projects.

Don’t settle for iPaaS and ESB when you can do so much more with Liaison’s value-added approach to integration. Want to learn more? Contact our data experts to inquire about Liaison ALLOY.

esb, integration, ipaas

Published at DZone with permission of Jonathan Razza , DZone MVB. See the original article here.

Opinions expressed by DZone contributors are their own.

{{ parent.title || parent.header.title}}

{{ parent.tldr }}

{{ parent.urlSource.name }}