Kong vs OpenResty: What are the differences?

1. Performance: Kong is built on top of OpenResty, but it adds additional features and functionalities to enhance performance. Kong provides a high-performance API gateway with built-in load balancing and caching capabilities. It uses a hybrid event-driven and threaded architecture to efficiently handle a large number of requests simultaneously. On the other hand, OpenResty is a web platform that embeds the Lua programming language into NGINX, allowing developers to extend NGINX with custom Lua scripts. While OpenResty can also achieve high performance, it requires writing custom Lua code to implement advanced functionalities.
2. Plugin Ecosystem: Kong boasts a comprehensive plugin ecosystem, offering a wide range of pre-built plugins that can be easily integrated into API gateway workflows. These plugins enable functionalities such as authentication, rate limiting, request and response transformations, and logging. OpenResty, on the other hand, does not have a built-in plugin ecosystem. Developers need to write custom Lua scripts or leverage existing Lua libraries to implement similar functionalities.
3. Administration and Configuration: Kong provides a user-friendly administration API and web interface, making it easy for developers and administrators to manage the API gateway and configure its various components. It offers fine-grained control over routing, request/response transformations, and security policies through a declarative configuration approach. OpenResty, being an extension of NGINX, relies on NGINX's configuration language and requires manual configuration file editing to manage the server and its components.
4. Enterprise Support: Kong offers enterprise-grade support through its commercial offering, Kong Enterprise. This includes features like professional support, on-premises installations, and enterprise plugins specifically designed for large-scale deployments. OpenResty, on the other hand, does not have a commercial offering and mainly relies on community support.
5. Logging and Analytics: Kong provides built-in logging and analytics capabilities, enabling developers and administrators to monitor and analyze API traffic. It supports various log storage and analysis providers, making it easier to integrate with existing monitoring and analytics systems. OpenResty, being an extension of NGINX, relies on NGINX's logging capabilities that require manual configuration and may require additional tools or scripts for log analysis.
6. Ease of Deployment: Kong offers various deployment options, including on-premises, cloud, and Kubernetes-based deployments. It provides pre-built Docker images and Helm charts for easy setup and configuration in containerized environments. OpenResty, being a web platform, can be deployed in similar environments but requires manual setup and configuration, potentially involving more effort.

In summary, Kong provides a feature-rich API gateway built on top of OpenResty, offering enhanced performance, a comprehensive plugin ecosystem, user-friendly administration and configuration, enterprise-grade support, built-in logging and analytics capabilities, and easy deployment options. OpenResty, while highly performant and extensible with Lua, requires more manual effort for configuration, lacks a built-in plugin ecosystem, and does not offer commercial support.