What Ruby Runtime Environment Should You Use?

Individuals who use Ruby as a primary programming language may not be familiar with the concept of a “Ruby interpreter and runtime.”

The explanation for this lies in the fact that you may have never considered the possibility of having more superior options available for the current Ruby interpreter.

Nevertheless, Ruby’s implementation is not a fixed choice as there could be alternative options available that might be better suited to your requirements.

Regrettably, there is a shortage of guidance accessible regarding which Ruby interpreter and runtime to select or even a comprehensive list of the Ruby interpreters that are available.

The primary objective of this article is to provide a summary of several contemporary interpreters and runtimes, outlining their capabilities and the significant considerations that must be taken into account when choosing an appropriate option for a specific project.

The interpreter’s role is clearly defined.

In order to achieve successful input and output, efficient communication is crucial. Languages play a vital role in establishing this connection, with their fundamental elements, such as grammar, lexicon, and syntax, ensuring precise comprehension and consensus between various parties.

In cases where the parties involved do not use the same language, translation or interpretation may be required to facilitate input or output.

To enable machines to perform tasks, they must receive clear and accurate instructions, which makes the idea of interpretation or translation at the core of programming languages.

The machine code is the most basic type of computer instruction, and it is the sole language that the CPU can instantly understand.

Since it is impossible for humans to enter machine code manually, programmers use source code written in high-level languages to generate binary files that can be executed by computers.

An interpreter or compiler is a software that converts human-readable source code into machine code.

Interpret or Compile?

Unsure whether you require a Ruby compiler or an interpreter? Look no further for the answer to your query.

Each programming language necessitates a specific compiler or interpreter to be included in its corresponding development kit. For example, the Java Virtual Machine (JVM) compiler and the CPython Interpreter are used to convert high-level source code into machine language for the Python programming language.

So, what sets apart a compiler from an interpreter?

  • An interpreter executes the code written in a programming or scripting language directly without first translating it into machine code.
  • Opposed to an interpreter, a compiler produces an object (also known as a binary representation) of the program, which can be executed by the machine after being linked.
  • An interpreter is necessary for Ruby to function because the language’s code was designed for this purpose.

Interpreted Language vs Compiled Language

During runtime, interpreted languages convert their source code to machine code, whereas compiled languages do this before running the program.

On the other hand, a program written in a compiled language needs to be converted from its source code to machine code before it can be executed.

Each approach has its advantages and disadvantages.

  • Interpreted languages can provide more flexibility, better platform portability and easier debugging, but they may suffer from slower performance and speed because of the need to interpret code during program execution.
  • Compiled languages, however, are faster as they optimize their code for various platforms before the program begins.

Translating Ruby Code

Ruby’s interpreter is versatile and can quickly adapt to changes in the language. Unlike Python, Ruby does not provide an extensive guide to its syntax and grammar.

Ruby‘s website can serve as a resource for documentation and community support.

To verify that a Ruby implementation is accurately interpreting the code, programmers often depend on the community-led Ruby Spec Suite – a series of tests.

Running the Ruby Interpreter

Once you have installed Ruby, you can execute Ruby programs by entering the following command:

To display “Hello, world!” using Ruby programming language, use %ruby -e.

The “Hello, World!” Program

Using the -e option in the interpreter’s command line directs the interpreter to execute the code on the specified line.

Usually, you’ll save your Ruby code in the native.rb file format and instruct the interpreter to execute it.

“% ruby hello.rb” command

The “Hello, World!” Program

The Need for Substitutes

As long as there are substitutes available, the language must be propelled forward despite its limitations.

Ruby has several implementations, each customized to fit specific conditions or platforms. Selecting the right implementation can result in significant enhancements in the performance and memory usage of Rails applications.

Before the advent of Ruby Version Interpreter (RVI), MRI was the dominant Ruby interpreter. However, it was observed that, in comparison to the concurrency capabilities of JRuby and Rubinius, MRI lacked performance and had problems with memory and garbage collection.

Understanding Comp-Interpreters

Here, we’ll discuss some of the widely used alternative interpreters and their typical applications.

1. YARV (Yet Another Ruby VM)

YARV interpreter is the preferred interpreter for stack-based systems. It replaced the MRI interpreter, which was introduced in the Ruby 1.9 release (also known as CRuby). It currently remains the recommended interpreter as of Ruby 3.1.

YARV converts the source code into a set of instructions that can be executed by the Ruby Virtual Machine when running a Ruby application. The emulation provided by this VM enhances program stability and predictability, allowing it to execute on any system.

2. CRuby/MRI (Matz’s Ruby Interpreter)

Previously, we employed an interpreter called MRI, which stands for Matz Ruby Interpreter, named after the creator of Ruby, Yukihiro Matsumoto.

The first Ruby interpreter was famously written in C, giving rise to the name CRuby. MRI/CRuby uses an abstract syntax tree to parse Ruby code, while YARV employs the parse Ruby language.

3. JRuby

JRuby is a Ruby language interpreter, similar to CRuby, which operates on the Java Virtual Machine (JVM). This enables Ruby to join other languages based on the JVM, such as Clojure and Scala.

Because of its compatibility with the Java platform, the JRuby interpreter can operate on a variety of systems. This enables it to be employed in multiple environments, including mobile applications, desktop machines, and servers. Additionally, it can utilize the Java platform’s built-in and third-party libraries.

In long-running web servers, performance is crucial, and JRuby is well-equipped to handle multithreaded and concurrent processing. JRuby features excellent garbage collection, albeit with a large memory footprint and a slow start-up time. Troubleshooting CLASSPATH errors can be difficult if external libraries are employed. Ruby on Rails offers a comprehensive API that allows web developers to incorporate the latest features and functionality into their projects.

It’s worth mentioning that JRuby does not offer support for various essential characteristics of Ruby, such as the C Application Programming Interface (API) and the ObjectSpace module, which provides thorough introspection abilities.

Despite its limitations, the JRuby Interpreter is a preferred option because it allows developers to utilize the most efficient optimizations for their Rails applications. This includes employing the JIT compiler and native Java objects and Application Programming Interfaces.

4. Rubinius

Rubinius, a Ruby interpreter, employs a minimal amount of C code for program interpretation in order to outperform competing Ruby interpreters like YARV, CRuby/MRI, and JRuby.

Rubinius is developed using C++ as the underlying language, with the vast majority of the remaining code written in Ruby. It is also a low-level virtual machine that can be used as a general-purpose runtime for dynamic programming languages, which is an additional advantage.

This arrangement enables Rubinius code to function with improved performance, memory management, and reduced overhead.

If you require fast Rails servers without JRuby’s drawbacks, this Ruby interpreter may be the solution you’re looking for.

5. Opal

With the help of a transpiler called Opal, the Ruby programming language can be transpiled into JavaScript. Opal is quick, with performance comparable to runtime, and its small size comes preloaded with the Ruby core library.

The Ruby interpreter is evaluated against only a limited portion of RubySpec, the sole one that can be trusted to behave consistently. However, challenges remain, such as the inherited traits of JavaScript runtimes and implementations.

Opal can be utilized either independently or integrated into an existing pipeline, such as the Rails Asset Pipeline. This allows automation of tasks like converting somefile.js.rb into the corresponding JavaScript code.

If you intend to create a comprehensive online application using Rails, Opal might be the perfect choice. This is because it permits Ruby code to be executed on the server-side and JavaScript to be executed on the client-side through Opal.

Ruby’s syntax offers an advantage over typical JavaScript libraries like jQuery, as it can automatically recognize interactions with JavaScript APIs. This makes it simple to transition to JavaScript seamlessly.

Opal’s features and constraints arise from its foundation in JavaScript. This implies that it is susceptible to the same runtime and architectural decisions as JavaScript, sadly.

6. RubyMotion

RubyMotion is a commercially available tool that facilitates the creation of cross-platform applications for iOS and Android. It includes a Ruby interpreter and language bindings that enable Ruby to interact with Cocoa APIs.

Its workflow based on terminals is what sets it apart from others. This provides you with command line access and control over your applications.

To enhance iOS and Android applications and projects, Ruby Gems are an option. Besides, it supports Cocoapods natively and has built-in functionality.

Ruby motion has a completely functional debugger and behavior-driven testing built right into it.

7. mRuby

Are you tired of online Ruby Interpreters that either require excessive bandwidth or bombard you with intrusive advertisements?

If you are looking for a Ruby interpreter that is fast and small in size, mRuby may be the ideal choice for you.

It is designed as an integrated version of Ruby that can be utilized for programming microcontrollers like Raspberry Pi and scripting in native applications.

Moreover, the mRuby interpreter could be the most suitable choice for your project if it has strict limitations.

What Is the Recommended Ruby Runtime and Interpreter? Our Opinion

The best choice for converting your online app to a mobile app depends on the specifics of your project – mRuby and Ruby Motion could be the most suitable options. However, if you want to create a more advanced app, the Ruby interpreter offers various gems and libraries that can be configured.

The most recent version of Ruby now includes the YARV Ruby interpreter, which is considered the best for Rails development.

If speed is your top priority, you might prefer to consider JRuby and Rubinius over the CRuby/MRI interpreter.


Having multiple development strategies available to deal with various projects, each with their own unique specifications and requirements, is beneficial.

No single Ruby implementation can fulfill all these requirements; hence, it is necessary to assess the best options to identify which one performs optimally in each domain.

Currently, there are several high-quality Ruby interpreters and runtimes available, including YARV, CRuby/MRI, JRuby, Rubinius, Opal, Ruby Motion, and mRuby. This article can assist you in determining which of these alternatives might be the most suitable option for your next project if you are unsatisfied with your current interpreter.

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