Difference Between Apache APISIX and Kong Gateway in API Routing

The Critical Role of an API Gateway in Modern Architecture

When building distributed systems, we create dozens or hundreds of smaller services that talk to each other. In practice, this means we need a single entry point to organize traffic coming from outside, such as mobile apps and websites. This entry point is the API gateway, a software that acts like the front desk of a corporate building. It validates whether callers have permission to access the API, forwards requests to the correct server, and protects internal systems against abuse.

With the growth of microservices, the requirements for this digital front desk changed drastically. Forwarding data packets is no longer enough; the system must be extremely fast, handle thousands of concurrent connections per second, and allow rule changes without taking down the system. Exactly in this scenario, two open-source tools stand out: Apache APISIX and Kong Gateway. Both solve the problem of directing traffic, but do so with distinct engineering philosophies.

Architecture and the Technological Core of Each Tool

To understand the behavior of Apache APISIX and Kong Gateway, we must look at the engine running under the hood. Both use NGINX, a web server famous for extremely high performance and low memory consumption when managing concurrent connections. However, how they manage configuration and data storage completely changes the operational experience in production environments.

Kong Gateway traditionally relies on a relational database, usually PostgreSQL, to store all its routes, security certificates, and plugin configurations. When you change a rule, Kong reads that change from the database and updates memory. Apache APISIX, on the other hand, adopts a fully decentralized approach. It uses etcd, a distributed, highly consistent key-value store similar to what Kubernetes uses to store cluster states. In practice, this means APISIX eliminates dependency on a traditional relational database and delivers nearly instantaneous configuration updates across globally distributed servers.

Performance and Latency in Traffic Routing

Traffic routing is the primary function of any gateway. It takes the URL typed by the client, reads HTTP headers, and decides which internal address should receive that request. In high-scale systems, every millisecond counts, as hundreds of cascading calls can happen to render a single web page on the user's browser.

Apache APISIX was built from the ground up with an obsessive focus on performance and dynamic routing based on complex expressions. It uses the Lua language and LuaJIT technology, which compiles code at runtime to ensure speed close to compiled languages like C. In comparative load tests, APISIX frequently demonstrates lower latency and reduced CPU consumption when handling highly dynamic routes that change based on arbitrary request parameters.

Plugin Ecosystem and Extensibility

An API gateway rarely performs only basic routing. Most of the time, it needs to enforce security policies, limit requests per second (rate limiting), log usage metrics, and authenticate users via JSON Web Tokens (JWT). The flexibility to build and manage these behaviors defines the success of a gateway platform.

Kong Gateway features one of the most mature ecosystems on the market. It offers hundreds of official and community plugins, covering virtually any corporate need imaginable. Furthermore, Kong's enterprise support delivers advanced API lifecycle management features. Apache APISIX is not far behind, offering dozens of native plugins written in Lua, plus the ability to develop extensions in other languages like Python, Go, and WebAssembly, attracting teams with diverse technical backgrounds.

Operational Experience and Learning Curve

The choice between infrastructure tools also involves the human factor: how much time will your engineering team spend learning, operating, and troubleshooting the chosen tool? Extremely fast software loses its value if daily operations are complex enough to cause frequent outages due to human error.

Operating Kong Gateway is relatively straightforward for teams already familiar with traditional relational database management and the NGINX ecosystem. Its documentation is vast and many ready-made community solutions exist. Conversely, operating Apache APISIX requires the team to understand how etcd works, adding an extra layer of architectural complexity. However, this same etcd-based architecture removes concurrency bottlenecks associated with relational databases, facilitating automation in cloud-native infrastructures.

Final Considerations on Gateway Selection

The decision between Apache APISIX and Kong Gateway directly depends on your architectural scenario and your company's operational goals. If your ecosystem already runs heavily on relational databases and you seek a mature ecosystem with a wide range of ready plugins, Kong Gateway delivers immediate stability and adoption ease.

On the other hand, if your top priority is absolute performance in high-concurrency scenarios, instant configuration updates without relational database dependencies, and total flexibility in plugin development using WebAssembly, Apache APISIX presents itself as a modern and extremely robust choice for advanced microservices architectures.