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API Gateway: the new spider in the web?

Let’s face it: with the upcoming of cloud and cloud-to-cloud, we entered a new era. An era where besides the traditional Enterprise Service Bus (ESB), a new spider entered the web of the IT world. A spider with legs in the inside (the traditional on premise world) and legs in the outside (external world of the clouds). This new spider is called the API Manager, or sometimes called by its main purpose: API Gateway. Its natural habitat is the demilitarized zone (DMZ) between the (fire) walls of the Enterprise and the Cloud. So, what does that mean and what are the consequences and implications of this new key player? For now I would say they can easily coexist.

ESB Integration and legacy systems

ESB integration may still be necessary when you have to deal with legacy systems. In the business of Enterprise Application Integration (EAI), the ESB provides the features to implement Service Oriented Architecture (SOA). Some of the basic services of both the ESB and the API manager/gateway are:

  • Transformation, Orchestration, and Mediation
  • Quality & Lifecycle Management
  • Manageability (Governance & Administration)
  • Security (ESB to a lesser extend)
  • Monitoring, Control, and Complex Event Processing (CEP)


Two different concepts

So, is this what we call putting new wine into old wineskins? – Yes and No. The ESB and API Gateway both contribute to SOA but they are two different concepts. An API Gateway provides a central access point for managing, monitoring, and securing access to your publicly exposed web services, where an API Gateway also acts as a proxy for your web services. The API Gateway is strategically located between the external consumer and your internal services. Added values of the API Manager may be:

  • Virtualization
  • Scalability and elasticity
  • High availability
  • Development simplicity
  • Throttling

An ESB is an internal “Bus” that allows applications and services to communicate with each other in a decoupled fashion. All applications are not connected with each other directly, but indirectly by publishing messages to – and receiving messages from a central bus.


The API Gateway is not necessarily a replacement for an ESB, but rather an enhancement

The API Gateway is not necessarily a replacement for an ESB, but rather an enhancement for a Service Oriented Architecture (SOA). However ESB’s are also central access points and can also perform monitoring and security of services from different (message) providers and/or consumers.

ESB and API platforms

Where ESB is intended for internal consumption the API Gateway is intended for external consumption. Because of the overlap of key features of ESBs and API platforms, you can use an ESB for external access or an API platform for internal access. So YES YOU CAN use the API gateway for communications between your internal services, but NO that does not necessarily make it the best solution. In the end the options to choose from are relatively simple:

  1. Point to point (in very simplistic situations)
  2. ESB
  3. API Gateway (in some greenfield situations)
  4. Combination of both ESB and API Gateway

Are you convinced of the need for investing in ESB and/or API Gateway, or perhaps planning a rollout of an ESB and/or API Management Platform? We have partnerships with multiple vendors and can assist you throughout the whole process, from a request for proposal (RFP) to platform enablement and platform adoption.

Our consultants have led rollout processes in multiple domains and will guide you in the creation of a plan and guide you through the process of delivering a solid solution.