Erlang Programming Language: Definition, Examples


Erlang is a general-purpose, concurrent, functional programming language. It was initially created in the 1980s by Ericsson to improve the development of telephony applications. Today, it’s primarily used in distributed systems due to its real-time capabilities, fault tolerance, and scalability.


The phonetics of “Erlang Programming Language” would be: “UR-lang Proh-gram-ming Lan-gwidge”.

Key Takeaways

  1. Concurrency and Fault Tolerance: Erlang is synonymous with concurrency and fault tolerance. It enables developers to create multiple processes without worrying about conflict, and if a process fails, it will have zero effect on other processes. The fault tolerance feature allows the system to recover automatically after failures with minimal interruption.
  2. Real-time Systems: Erlang is a functional programming language specifically designed for creating real-time systems. It’s widely-used in telecommunication systems, banking, and eCommerce applications. The language is ideal for building applications that demand high-availability, concurrency, and distribution.
  3. Hot Swapping: Erlang supports hot swapping, meaning it allows code to be changed or upgraded without stopping the system. This makes Erlang a preferred language for systems that need to operate non-stop and with great reliability like telecom routing systems or web servers.


The Erlang Programming Language is important due to its unique properties and design focused on building robust, fault-tolerant systems. Developed by Ericsson for telecommunications applications, Erlang has built-in support for concurrency, distribution, and fault tolerance, making it ideal for building large-scale, real-time, and distributed systems. Its functional programming style offers pattern matching and dynamic typing, enhancing its capabilities in system design. It’s widely used in telecommunications, banking, ecommerce, computer telephony, and instant messaging applications, marking its significance in such high-demand sectors. Furthermore, companies like WhatsApp have proven Erlang’s capability to handle massive concurrency in real-world applications.


The Erlang Programming Language is designed with an acute focus on concurrency, fault tolerance, and real-time systems. This programming language shines in fields where you need simultaneous operations running in conjunction with each other. It was originally developed by Ericsson in the late 1980s to enhance telecommunication systems and has since found utility in online gaming, e-commerce, computer telephony and instant messaging platforms. Its ability to support hot swapping, a feature enabling code updates without needing to stop or restart the system, makes Erlang uniquely suitable for systems requiring constant uptime.Erlang is popular within systems that demand seamless, non-stop performance in production. For example, use of Erlang is widespread in banking, finance, and ecommerce sectors where system downtime can have significant implications. It is also the backbone of many messaging systems and databases like WhatsApp and Riak, underpinning the real-time exchange of data among billions of users. Thus, the purpose of Erlang lies in ensuring high availability, fault tolerance and scalability in systems requiring robust, real-time processing and communication.


1. WhatsApp: WhatsApp, a widely used messaging app across the globe, was built using the Erlang Programming Language. It was chosen for its superior performance in handling numerous concurrent connections, making it perfect for a platform where billions of messages are transmitted daily.2. T-Mobile: This popular telecommunications company also uses Erlang for its SMS and authentication systems. The language’s scalability and fault-tolerance features make it ideal for managing the vast amount of user authentication requests and SMS communications.3. Ericsson: As the company where Erlang originated, Ericsson uses this programming language primarily in their telecoms systems to ensure the reliable and efficient transfer of calls and data.

Frequently Asked Questions(FAQ)

Q: What is the Erlang Programming Language?A: Erlang is a functional, general-purpose programming language and runtime environment that was developed by Ericsson. It was primarily designed for real-time systems and telecommunication systems with requirements on high availability and low latency.Q: Who developed Erlang?A: Erlang was developed by Ericsson, a Swedish multinational networking and telecommunications company, in the late 1980s.Q: What kind of language is Erlang?A: Erlang is a functional programming language. This means that it emphasizes the evaluation of mathematical functions and avoids changing-state and mutable data.Q: What are the key features of Erlang?A: Erlang is known for its features like hot swapping, where code can be changed without stopping a system. It has strong support for concurrency, distribution, and fault tolerance. It promotes a declarative and functional coding style.Q: What is the syntax of Erlang like?A: Erlang’s syntax is unlike most common programming languages. It was built for readability over write-ability, which means it’s designed to be easier to understand than to write.Q: What is hot swapping in Erlang?A: Hot swapping is a feature in Erlang that allows code to be changed or upgraded without needing to stop or restart the system. This is especially valuable in systems requiring high availability.Q: In which industries is Erlang used?A: Erlang is mostly used in telecommunications, banking, eCommerce, computer telephony and instant messaging, as its characteristics enable to build reliable, highly-concurrent and low-latency systems.Q: What is OTP in Erlang?A: OTP (Open Telecom Platform) is a collection of modules and standards designed to help in building applications in Erlang. It provides numerous ready-to-use components for use.Q: Can I use Erlang for web development?A: Yes, with frameworks such as Cowboy and Yaws, Erlang can be very effective for back-end web development.Q: How does Erlang handle errors?A: Erlang is designed around the idea of “let it crash” philosophy. Instead of trying to catch errors and exceptions, Erlang processes are designed to fail fast, then get restarted by a supervisor process. Q: What is the performance of Erlang like?A: Erlang allows for horizontal scalability and can handle large numbers of lightweight concurrent processes. It’s designed to dynamically handle load and provide soft real-time performance, but may not be as fast as languages such as C++ or Java for compute-intensive tasks.

Related Finance Terms

  • Concurrent Programming
  • OTP (Open Telecom Platform)
  • Functional Programming
  • Beam VM (Erlang’s Virtual Machine)
  • Hot Code Swapping

Sources for More Information


About The Authors

The DevX Technology Glossary is reviewed by technology experts and writers from our community. Terms and definitions continue to go under updates to stay relevant and up-to-date. These experts help us maintain the almost 10,000+ technology terms on DevX. Our reviewers have a strong technical background in software development, engineering, and startup businesses. They are experts with real-world experience working in the tech industry and academia.

See our full expert review panel.

These experts include:


About Our Editorial Process

At DevX, we’re dedicated to tech entrepreneurship. Our team closely follows industry shifts, new products, AI breakthroughs, technology trends, and funding announcements. Articles undergo thorough editing to ensure accuracy and clarity, reflecting DevX’s style and supporting entrepreneurs in the tech sphere.

See our full editorial policy.

More Technology Terms

Technology Glossary

Table of Contents