Design and Implementation of a High‑Performance API Gateway Using Spring WebFlux and Nacos

Background – Inspired by the Soul gateway project, the author built a high‑performance gateway (named ship‑gate ) from scratch, aiming to overcome the lack of a management console due to limited front‑end skills.

Design – Technology Selection – Two main approaches were considered for asynchronous request handling: Tomcat/Jetty + NIO + Servlet 3 (widely used by JD, Zuul) and Netty + NIO (used by VIP.com with higher throughput). The author chose Spring WebFlux (built on Netty) to avoid manual HTTP handling.

Requirements – The gateway must support custom routing rules (by version, header, query), cross‑language HTTP, high performance, high availability, gray (canary) releases, interface authentication, and multiple load‑balancing algorithms.

Architecture – The system is divided into modules such as ship-client-spring-boot-starter , ship-server , and ship-admin . Modules communicate via Nacos for service registration/discovery and share routing/metadata through WebSocket synchronization.

Implementation – Client Starter

public class AutoRegisterListener implements ApplicationListener
{ /* registration logic, shutdown hook, Nacos interaction */ }

Implementation – Server Core

public class PluginFilter implements WebFilter { /* parses app name, builds plugin chain */ }

public class PluginChain extends AbstractShipPlugin { /* manages ordered plugin execution */ }

public class DynamicRoutePlugin extends AbstractShipPlugin { /* selects service instance, forwards request */ }

Data Synchronization – NacosSyncListener periodically updates instance weight and enabled plugins to Nacos; DataSyncTaskListener pulls instance data into local caches; WebSocket servers/clients ( WebsocketSyncCacheServer , WebsocketSyncCacheClient ) push route rule changes in real time.

Testing – The author deployed Nacos, ship‑admin, and two ship‑example services (gray_1.0 and prod_1.0). A header‑based routing rule was added, and Postman requests verified that traffic with name=ship was routed to the gray instance. Performance testing with wrk on a MacBook Pro achieved ~9,400 QPS with 20 threads and 500 connections.

Conclusion – Building a gateway is approachable once you start coding; the project demonstrates dynamic routing, load balancing, and seamless configuration sync, with all source code available on GitHub.