concurrent runtime / concurrency framework

Pony is an open-source, actor-model, capabilities-secure, high performance programming language

Actix is a Rust actor framework and concurrent programming toolkit designed for building applications that manage state through an asynchronous messaging system. It provides a model where independent actors serve as autonomous units of state and logic, communicating via strongly typed messages sent to unique addresses. The framework distinguishes itself by isolating state within these actors, allowing internal data to be mutated safely during message handling without the use of locks or mutexes. It employs an asynchronous mailbox system to buffer incoming requests and uses supervision strateg

Lunatic is a WebAssembly runtime and concurrent process manager that implements an Erlang-inspired model of lightweight concurrency and fault tolerance. It functions as a distributed actor system where isolated processes communicate via message passing across a network of linked nodes. The system utilizes a WebAssembly sandbox environment to isolate memory and restrict system call permissions for each individual process. This capability-based security model ensures that processes are sandboxed to safely execute untrusted code. The platform provides a fault-tolerant supervision tree for hiera

libco is a C++ coroutine library and user-space task orchestrator designed for cooperative multitasking and high-concurrency execution. It functions as a high-concurrency network framework and a synchronous-to-asynchronous wrapper that allows blocking system calls and socket functions to run asynchronously without modifying existing business logic. The project utilizes a specialized stack-copying context switching model to support millions of simultaneous TCP connections on a single machine. It includes a high-performance time wheel scheduler for managing asynchronous background jobs and dela

Go is a statically typed, compiled programming language designed for building scalable, concurrent software. It provides a memory-safe execution environment that combines a high-performance runtime with a self-hosting compiler toolchain, enabling the creation of statically linked machine code binaries without external dependencies. The language is built around a structural type system that uses interfaces for polymorphism and a concurrency model based on lightweight, stack-based coroutines that communicate through channels. The language distinguishes itself through a runtime that features a c

Crossbeam is a concurrency toolkit for Rust providing low-level primitives for writing multi-threaded programs. It focuses on lock-free data structures and memory management primitives designed for shared-memory concurrent environments. The project includes a work-stealing scheduler that uses double-ended queues to balance workloads across multiple processor cores. This system enables the implementation of work-stealing deques to distribute tasks and prevent bottlenecks. The toolkit covers broader capabilities for parallel algorithm development, multi-threaded task scheduling, and general co

oneTBB is a C++ parallelism library and framework designed to add multi-core parallelism to applications. It provides a task-based parallelism model that maps logical computational tasks to available hardware cores to eliminate the need for manual thread management. The library functions as a multi-core scaling tool, utilizing generic templates to scale data-parallel operations across processors for portable performance. It employs a task-based framework to ensure computational workloads are distributed across hardware resources. The project covers shared memory parallelism, multi-core task

Akka is an actor model framework and distributed systems platform used to build concurrent and distributed applications. It provides a toolkit for managing multi-threaded state and behavior through asynchronous message passing, allowing developers to create concurrent applications without manual locks or synchronization. The system functions as a cluster management and event sourcing framework, automating the scaling and coordination of high-availability clusters. It enables the deployment of elastic services that coordinate workloads across multiple network nodes and ensures fault tolerance

Swoole is a coroutine-based concurrency library and IO framework for PHP. It provides a system for building high-performance network servers and applications by bringing asynchronous, event-driven, and coroutine-based concurrency to the PHP runtime. The project distinguishes itself by implementing user-space coroutine scheduling and non-blocking IO interception, which transforms standard blocking network and file operations into asynchronous actions. It further enables high-speed data exchange across multiple PHP processes through shared memory management and specialized data structures. The

cppcoro is a C++ coroutine library and concurrency toolkit providing primitives for asynchronous tasks, lazy generators, and non-blocking execution. It functions as an asynchronous I/O framework for managing network sockets and file operations through an event loop. The library features a work-stealing thread pool for distributing tasks across multiple cores and a set of async generators for producing lazy sequences of values both synchronously and asynchronously. It includes a concurrency toolkit with async mutexes, latches, and shared tasks to coordinate multi-threaded execution. Its capab

Tokio is an asynchronous runtime for the Rust programming language, designed to manage and execute concurrent tasks efficiently. It provides a multi-threaded execution environment that schedules lightweight tasks across available processor cores, utilizing a work-stealing scheduler to balance computational load. By employing a poll-based execution model and waker-based notifications, the runtime drives asynchronous operations forward without requiring active polling loops, ensuring efficient resource utilization. The project distinguishes itself through a comprehensive suite of tools for high

Swift is a high-performance, general-purpose programming language designed for safety and speed. It features a modular compiler front-end that transforms source code into optimized machine binaries, utilizing a value-oriented type system that prioritizes predictable state management through value and reference types. The language is built on a task-based concurrency model that schedules asynchronous operations across multicore hardware to ensure data race safety. The project distinguishes itself through a native, bi-directional interoperability mechanism that allows for direct integration wit

Smol is a lightweight Rust asynchronous runtime and task executor. It provides a suite of foundational tools for scheduling and executing asynchronous futures, managing background workloads, and handling non-blocking network and file operations. The project includes a compatibility layer for adapting asynchronous types and execution contexts, enabling futures to run across different runtime ecosystems. It also features a mechanism to offload synchronous I/O and CPU-intensive operations to dedicated worker thread pools to prevent runtime stalls. Its capabilities cover non-blocking network I/O

async-std is a Rust asynchronous runtime and non-blocking I/O library. It serves as an asynchronous standard library, providing a set of alternatives to the core Rust library for managing concurrent tasks, networking, and file system access. The project implements a standard-library-mirrored API, offering asynchronous versions of existing synchronous types to maintain a familiar interface. This approach allows for asynchronous Rust development using an interface that reflects the ergonomics of the language's standard library. The runtime includes a task executor for scheduling and executing

Kotlinx.coroutines is a library for managing non-blocking background tasks and structured concurrency within the Kotlin programming language. It provides a framework for executing concurrent operations and synchronizing shared state, replacing traditional thread management and complex callback chains with lightweight primitives. The library utilizes a structured concurrency hierarchy to organize hierarchical background tasks, ensuring that lifecycle management, cancellation, and timeout handling propagate automatically to prevent resource leaks. It employs continuation-passing style transform

Workerman is an event-driven asynchronous socket framework for PHP. It provides the core components necessary to build high-concurrency network servers, including an asynchronous TCP framework, a coroutine library for task management, and dedicated implementations for HTTP and WebSocket servers. The project enables the development of specialized network services using custom frame-based communication protocols. It supports both inbound concurrent server implementation and asynchronous outbound connectivity to remote services. The framework covers a broad range of network programming capabili

oneAPI Threading Building Blocks (oneTBB)

Rayon is a data parallelism library for Rust that provides a framework for converting sequential computations into parallel operations. It enables the transformation of standard data structures and loops into parallel iterators, allowing workloads to be distributed across multiple processor cores. By utilizing a work-stealing scheduler, the library dynamically balances tasks to maximize throughput and minimize execution time. The library distinguishes itself through its focus on safe, scoped task synchronization, which ensures that all spawned operations complete before a scope exits to preve

Taskflow is a C++ task-parallel framework designed to build high-performance parallel workflows and complex dependency graphs. It provides a programming model that organizes computational work into directed acyclic graphs, enabling developers to manage concurrency, resource scheduling, and task dependencies across multi-core CPUs and GPU accelerators. The framework distinguishes itself through its ability to orchestrate heterogeneous systems, allowing for the integration of hardware-accelerated kernels and memory operations into unified execution pipelines. It supports dynamic runtime subflow

Concurrent Ruby is a comprehensive concurrency toolkit for the Ruby language that provides thread-safe data structures, synchronization primitives, and asynchronous execution patterns. It implements core concurrency abstractions including an actor model framework where isolated actors communicate through asynchronous message passing, a future and promise system for composing non-blocking operations, and thread pool executors that manage reusable worker threads for concurrent task execution. The library distinguishes itself through a broad set of coordination mechanisms that go beyond basic th