Lua is an open-source scripting language known for being lightweight, performant, user-friendly, and flexible enough to support numerous use cases. Teams can embed Lua within supported applications without worrying about major compatibility or complexity concerns. The language is relatively simple and can support object-oriented, data-driven, procedural, functional, and descriptive programming styles with ease. 

Lua is developed and maintained by a team at the Pontifical Catholic University of Rio de Janeiro. Today, that responsibility has shifted to the LabLua group housed within the Department of Computer Science. An associated team at Tecgraf first created the Lua language in 1993, later releasing the first public version — Lua v1.1 — in mid-1994. The latest publicly available version of Lua is Lua v5.4.8, with Lua v5.5 set to be the next major release.

How does Lua work?

Lua shines due to its resource efficiency, running well on systems with either limited or robust computing resources. For example, memory management and garbage collection happen automatically with Lua. It also claims to be the fastest interpreted scripting language available — maintaining a small footprint (366KB compressed) that makes it readily embeddable across applications. A standard Lua API makes this possible. 

Lua primarily helps extend applications written in various programming languages by embedding the Lua interpreter into them. Lua is designed to work seamlessly with services written in C, C++, C#, Java, Perl, Ruby, Fortran, Erlang, and other programming languages. It's simple to use and employs meta mechanisms to enable feature development, rather than packaging standard features into one binary. Developers can readily bake Lua modules into their existing libraries without breaking their apps. 

As a result, Lua is incredibly versatile. Developers have used the language within embedded systems, smart IoT deployments, gaming, web development, industrial automation, education, robotics, and a host of additional uses. Lua is easy enough for newcomers to pick up (bringing simple projects into reach) while remaining powerful enough to support ambitious enterprise developments.

What are the benefits of Lua?

The power and simplicity of Lua give it plenty of advantages:

  • It consumes only 366KB of space compressed and 1.3M uncompressed, making it lightweight and easily embeddable. 

  • It supports numerous popular programming languages while unlocking deeper feature support, with a little creativity.

  • It supports multiple programming styles to best fit the project at hand, making it more usable in more situations.

  • It's relatively easy to learn and use, with a simple syntax. 

  • It's open source and thus free for anyone to use. 

Additionally, the Lua programming community remains active after years of development. Available resources are plentiful to help you get started, and answers to programming questions shouldn't be too far away.

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Does HAProxy support Lua?

Yes! HAProxy and HAProxy Enterprise come with a Lua interpreter that allows you to write custom Lua scripts that extend the load balancer’s functionality. HAProxy users can harness Lua to create custom alert mailers, fetches, actions, converters, services, and tasks with the Lua Event Framework. 

To learn more about Lua support in HAProxy, check out our Lua Event Framework Starter Guide or our Lua mailers tutorial.