Marcell Ciszek Druzynski

Compiled vs Interpreted Languages

Compiled vs Interpreted Languages

November 08, 2023

Let's discuss interpreter and compiled programming languages and the main differences and pros and cons between them.

In the world of programming, interpreters and compilers are distinct programs that handle source code written in high-level languages and convert it into machine code for computer execution. They achieve this through different methods, each with its own set of advantages and disadvantages.

Compiled Programming Languages: A compiler is a tool that takes an entire program's source code and translates it into machine code all at once. It thoroughly analyzes the source code, generating an executable file that can be directly run by the computer's operating system. The output of a compiler tends to be faster and more efficient because the machine code is optimized for the specific hardware and operating system it targets. However, the compilation process can be time-consuming, and different platforms and operating systems may require separate compilation steps.

Some well-known compiled programming languages include Go (Golang), Rust, C++, and C. Compiled languages typically offer faster and more efficient runtime performance but may have longer development times.

Interpreted Programming Languages: In contrast, an interpreter reads and executes code line by line or statement by statement. It doesn't generate an executable file; instead, it directly runs the source code. This flexibility allows interpreters to run code on different platforms without the need for a separate compilation step. However, interpreted code often runs more slowly compared to compiled code due to the interpretation process, which introduces overhead and doesn't optimize the machine code as much as a compiler.

Some notable interpreted languages include JavaScript, Python, Ruby, PHP, and Perl.

It's important to note that modern languages, like JavaScript, have evolved with the use of Just-In-Time (JIT) compilers, which compile code to machine code and then execute it. This blurs the line between interpreted and compiled languages, as they combine the advantages of both approaches.

To summarize, compiled languages offer faster and more efficient runtime performance but are slower to develop with, while interpreted languages are quicker to develop in but typically run more slowly and less efficiently. The choice between them depends on the specific needs and constraints of a programming project.

Short about JIT compilation

A JIT compiler, or Just-In-Time compiler, is a component in many programming languages, like Java and JavaScript. It translates high-level code into machine code on-the-fly when a program is executed, rather than ahead of time. This improves runtime performance since the machine code is optimized for the specific platform. JIT compilers are essential for running code efficiently in various environments, making it faster and more adaptable than precompiled code.

Mental Models

Compiled Process Analogy: Imagine the process of baking a cake. You have an old, well-documented recipe that's been used for decades. You can simply follow the recipe's instructions step by step to achieve the desired result. In this analogy, the recipe represents the already compiled code.

Interpreted Process Analogy: Now, let's consider the same scenario of baking a cake, but this time you don't have a written recipe. Instead, you have a knowledgeable friend right beside you who knows the recipe by heart. To bake the cake, you have to ask your friend for instructions step by step. This process might be a bit slower, but in the end, you'll still achieve the desired result. This friend represents the interpreter that provides instructions on the go.


In summary, compilers excel in handling larger, complex programs that require high performance and optimization. On the other hand, interpreters are more suitable for smaller programs, prototyping, and testing due to their faster development cycle and convenient debugging.

Many modern programming languages and environments combine these techniques to harness the advantages of both, such as Just-In-Time (JIT) compilers. JIT compilers compile code on the fly as it's being executed by the interpreter.

An example of this is the V8 engine, used to run JavaScript code in Google Chrome and Node.js. The V8 engine employs a multi-tiered architecture for Just-In-Time (JIT) compilation, enhancing the performance of JavaScript code execution.