ErlangOTP

Erlang/OTP, often written as ErlangOTP, is a programming language, runtime system, and standard library designed for building robust, concurrent, distributed systems. The term combines the Erlang language with the Open Telecom Platform (OTP), a collection of middleware, libraries, and design patterns. Erlang originated at Ericsson in the 1980s and was later released as open source; OTP provides a cohesive framework of abstractions that support fault-tolerant, scalable applications.

Core to Erlang/OTP is the BEAM virtual machine, which runs lightweight processes that communicate exclusively by message passing. This model enables massive concurrency and strong fault isolation. The OTP component offers generic behaviours and patterns such as gen_server, supervisor, and gen_statem, which help implement servers, supervision trees, state machines, and other architectural components. These patterns encourage design principles such as supervision hierarchies, hot code upgrades, and runtime reconfiguration to minimize downtime.

Applications are organized as OTP applications with structured code, configurations, and releases. The framework supports distribution across multiple nodes, enabling transparent messaging and code loading in a cluster. Deployment typically uses release tooling to package the runtime, applications, and configuration for production environments. Erlang/OTP is used in telecommunications, messaging systems, and high-availability services, with notable projects in chat servers, databases, and message brokers that require isolation between components and fault tolerance.