API terminology explained: Gateways, Portals, API Catalogs, Marketplaces

The API Management space has evolved a lot over the last two decades. With APIs becoming increasingly important as the foundational building blocks of digital transformation, this also means that the set of components commonly used in API Management has evolved accordingly.

We’ll have a brief look at the history of API Management and how this has shaped the evolution of API Management components. We’ll talk about API gateways, portals, catalogs, and marketplaces, and how these relate and fit into today’s picture of API Management.

A brief history of API Management

API Management took off when it became clear that carefully designed and aligned APIs can make a huge difference in how quickly and effectively an organization can change what it does, and how it does it.

APIs in this case are the building blocks of everything (digital) that an organization does, and this allows teams within an organization to be more loosely coupled. This, in turn, means that coordination overhead is reduced and that teams can move faster.

With APIs being the digital representation of teams internally and even externally, it becomes clear that these APIs must be managed. One very basic aspect is that they have to be secured. API gateways emerged when this became a repeating task that had to be addressed by all teams exposing APIs. API gateways allow to secure and manage APIs in an organization.

With gateways becoming shared components for API management, the question then arose about how to best expose and publish information about the APIs managed by a gateway. This is how API portals emerged; they complemented the ability to manage APIs in a gateway with the ability to find information about the APIs managed by a gateway.

The growing popularity of APIs means that APIs are published by an increasing number of teams and not necessarily always through the same gateway. In order to still allow all APIs to be visible in one place, API catalogs are establishing a layer that is independent of gateways. Because of this, catalogs are a better way to manage APIs in heterogeneous and continuously evolving API landscapes.

Since often APIs are used for collaborating with partners, it makes sense to also include APIs in the API Management that are external to an organization. This is where the concept of API marketplaces originates, which extends API Management beyond the scope of those APIs that are published by an organization to all APIs that are relevant for it.

Let’s have a closer look at these components.

API gateways

API gateways are the component closest to the actual API of all those listed here. An API gateway is typically managing all traffic from and to an API. By doing so, gateways can be used for a variety of functions.

Historically, securing the API by only allowing authorized access was the most important function of a gateway. They often also add convenience functions such as transforming between various data formats, so that an API limited to a certain format can still be made available supporting other formats, with the gateway transforming all traffic between the formats.

Gateways typically are put in place with an inside-out mindset: An API should be exposed to consumers but also should be secured. Thinking from the API perspective this means that a gateway is put in front of the API to provide the required functionality.

API Portals

The growing popularity and awareness around APIs means that more and more APIs are made available. More importantly, it becomes clear that one of the main values of APIs is to serve as interfaces between teams. But in order to do that, teams have to be able to find existing APIs for consumption, and gateways thus were extended to provide User Interfaces (UIs) that allow API consumers to browse and navigate APIs.

Portals were an interesting shift in perspective because they were motivated by an outside-in perspective: As somebody interested in building digital products and services, how can I find out which APIs there are which I can then use as digital building blocks?

Portals help to make APIs easier to find and consume. However, in most cases, portals are created and architected on top of gateways. This is not a problem as long as all APIs are managed with a single gateway. But the growing size and complexity of API landscapes mean that constraining API Management to scenarios where only one gateway is used is no longer a future-proof path forward.

API Catalogs

With API landscapes becoming more complex, it becomes clear that decoupling the technical API Management from the more business-oriented aspects of APIs is necessary. This is what API catalogs allow. They are independent of where an API is technically managed and therefore can readily manage APIs that are provided for example through different gateways.

This open approach means that the business value of APIs now no longer is tightly coupled with the technical aspects of API Management. With the right architecture, APIs can still be published and found in a timely manner, as long as the API catalog is not relying on any manual updates, but instead is populated in an automated fashion.

Catalogs, therefore, meet the needs of better separating technical and business-focused API management. However, as long as a catalog is populated with just an organization’s own APIs, it is still missing a critical component in the overall API Management space. That critical component is the ability to also manage APIs that are not provided by an organization, but are consumed by it and therefore need to be visible and managed as well.

API Marketplaces

API marketplaces in some form have been around for very long, but the initial variations used to be public marketplaces with the goal of making public APIs easier to find and use. However, the model of the marketplace now is being discovered from a more enterprise-oriented perspective, where the goal of the marketplace is to provide a unified view of all APIs that are relevant for an organization.

The marketplace extends the catalog idea by also allowing APIs to be added that are not managed by an organization. This means that the scope is further extended than before: Catalogs extended the scope from single gateways to being decoupled from gateways; Marketplaces further extend that scope to contain all APIs that matter for an organization.

API Management is evolving

API Management is evolving and so is the set of components that are used for API Management. In this article, we have looked at the evolution of API Management and briefly discussed the four concepts of gateways, portals, catalogs, and marketplaces.

If you want to learn more about these components, how they work, and how to use them for modern API Management, listen to this conversation with Axway expert, Jaime Ryan (VP, Product Management for the Amplify platform).