In this article, we will take a high-level look at the differences between an API proxy and an API gateway. When a developer publishes a public API, it's necessary for that API to have security policies and a way to hide backend logic from API consumers.

Decoupling your API from your backend services allows you to shield your apps from backend code changes, and allows users to call your API without worrying about availability. If changes are being made to an endpoint or if a new version is released, users can continue on without interruption. Additionally, an API proxy or an API gateway can help you easily and uniformly secure your API endpoints. This can add another layer of defense and prevent attackers from infiltrating your system.

Although an API proxy and gateway have some similarities, their differences are really what set them apart. Let's jump into the differences between the two solutions and identify which one is going to work best for your use case.

API Proxy

An API proxy is an interface that sits between your frontend and backend services. This abstraction helps to further decouple the frontend from the implementation details of your backend. The proxy will expose a URL that your front end will then use to access the API. When the request comes through to the proxy, the proxy then routes this request to the configured API endpoint, the response is returned to the proxy, and the proxy then returns the response back to the caller.

An API proxy works similarly to an API gateway in which it can handle data transformations, security, and routing. When you define a proxy, you can add transport security, monitoring (SLA, performance), quotas, and access levels to different APIs under your proxy.

Many businesses have existing services that are exposed by multiple applications, and these applications can be globally distributed which can make API management and reliability difficult. An API proxy may be a good solution for someone constructing a basic API who wants to apply some rudimentary security policies to it. However, at scale, and to meet real enterprise API needs, you are going to need an API gateway.

API Gateway

An API gateway can provide developers with much more customization over an API proxy, such as adding end-to-end security to your payload. An API gateway handles authentication, authorization, Denial of Service attacks, SQL injection checks, load balancing, caching, request shaping, orchestration, mediation, and transport security. Some API gateways even allow users to create brand new endpoints from existing services or create virtual endpoints that run solely on the gateway itself without any backend. As you can see, an API gateway provides all the features of an API proxy and much more.

As a developer, an API gateway can save you development time since you can focus solely on building application logic. This gives an advantage to developers so they don’t have to worry about building the features, such as security and caching, provided through the API gateway directly into their API code. Being able to leverage an API gateway's core infrastructure allows you to innovate quickly and rapidly prototype.

An API gateway provides a much richer set of capabilities than an API proxy. You can use an API gateway to construct an API by combining multiple existing services together, which is something that can't be done with an API proxy. A well-designed gateway will automatically optimize its configuration depending upon how it's used; it should be lightweight and offer exceptional performance. To learn more about reliable API gateways, and about the benefits of API gateways, check out our article on exactly that.

API Monitoring

Whether you decide on using an API gateway or API proxy, API monitoring is an essential tool that developers need to incorporate to ensure the reliability of their APIs. API monitoring allows developers to view real-time data including errors, exceptions, and other critical events. Additionally, developers can configure logging of API transactional data, and analyze API usage for insights and trends. Additionally, API monitoring can automate report generation, and help your business create holistic KPI and metrics data for both product managers and sales.

With Moesif, you can monitor the end-to-end user experience including all your API and frontend events. You can automatically get real-time alerts on your API performance issues or send out automated emails based on a user's behavior. Moesif is already integrated as a plugin with most API gateways available to developers, which is why you should consider using Moesif for custom API monitoring solutions. If you are using Kong, Moesif is already a top-rated community plugin that you can learn more about and integrate with by visiting this link. You can also plug Moesif directly into your API code by using one of our SDKs.

Should you choose an API Proxy or an API Gateway?

A well-designed API gateway will act as a proxy and allow you to turn on or off certain capabilities that aren't relevant to the needs of your application. Every business is different, so a customizable API gateway is necessary to tailor your APIs experience to your desired use case. Once you've chosen your API platform, you will want to make sure that your APIs are performing as intended. Implementing a lightweight, analytics solution such as Moesif complements your API gateway by giving you visibility and reporting. We recommend that developers use an API gateway so they can benefit from decoupling, reduce round trips, security, and cross-cutting concerns. Additionally, starting off your development journey with an API gateway will reduce technical debt since your developers won't need to implement an API gateway later on when their application or customer base scales.

Level up with analytics and monitoring

Regardless of your choice to use an API proxy or an API gateway, coupling your solution with an analytics solution is a must. Moesif offers end-to-end visibility of your APIs to help you build amazing API products. Deep insights into usage, trends, errors, and adoption can easily be uncovered within Moesif. Use an API gateway or proxy to deliver reliable and secure APIs to your users while using Moesif to ensure you are delivering unrivaled value. Since we support many of the most popular frameworks and API management platforms, integration with Moesif is simple and easy. Sign up for Moesif today to level up your APIs and use analytics and monitoring to augment your gateway or proxy solution.

This article was originally written for the Moesif blog, by Matt Tanner, head of developer relations.