Open-source alternatives to Seastar

Coost is a concurrent network framework and coroutine scheduler designed for building high-performance TCP, HTTP, and RPC services. It provides a set of tools for handling non-blocking IPv4 and IPv6 communication, integrating SSL encryption and a lightweight execution engine that manages concurrent tasks using shared stacks. The project features a specialized JSON RPC implementation for exchanging structured data over encrypted connections and a high-performance logging system. This logging infrastructure supports topic-based routing, frequency filtering, and automated stack trace capture for

The Rust Programming Language Book is the official technical guide and educational resource for the Rust language. It provides a comprehensive walkthrough of the language's design, focusing on its core identity as a systems programming language that enforces memory safety and high-performance execution without the need for a garbage collector. The project is distinguished by its focus on ownership, borrowing, and lifetime tracking, which allow the compiler to verify memory safety and thread safety at compile time. It covers the language's unique approach to zero-cost abstractions, including t

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

Vert.x is a reactive polyglot framework and asynchronous programming library for the Java Virtual Machine. It functions as an event-driven networking framework and toolkit for building non-blocking applications. The system enables the development of high-concurrency network services and event-driven microservices. It supports the creation of reactive services using multiple languages running on the JVM. The framework covers a wide range of capabilities including the management of HTTP and TCP network protocols, non-blocking file system access, and the integration of reactive clients.

Dpdk-ans is a high-performance userspace networking library and TCP/IP stack built on the Data Plane Development Kit. It implements a userspace network protocol stack that bypasses operating system kernel overhead and interacts directly with network interface hardware using poll mode drivers without interrupts. The project provides BSD-compatible socket APIs to enable legacy network applications to operate without requiring source code modifications. It supports multi-core receive scaling and traffic distribution to assign incoming network flows across dedicated CPU cores using hashing, alon

Lua is an embeddable scripting language written in ISO C, designed to be integrated into host applications for runtime customization. It provides a C-based scripting engine and a prototype-based object model that utilizes associative arrays and metatables to implement inheritance and complex data structures. The language features a cooperative multitasking system that manages concurrent execution threads via coroutines and an incremental garbage collector for automatic memory management. It includes a safe code sandbox to isolate global state and run untrusted scripts within a protected envir

ScyllaDB is a distributed NoSQL database engine designed for high-throughput data storage and low-latency performance at scale. It functions as a shard-aware platform that manages large-scale datasets across distributed clusters, providing a foundation for real-time applications that require consistent availability and operational stability. The system distinguishes itself through a shared-nothing architecture that distributes data across independent CPU cores to eliminate lock contention. It incorporates a user-space networking stack and an asynchronous event-driven engine to maximize hardwa

Trio is an asynchronous I/O runtime and concurrency library for Python. It provides a system for executing non-blocking network and disk operations through a centralized event loop and task scheduler. The library is built on a structured concurrency model, which ensures that asynchronous tasks are bound to a specific lifetime and cannot outlive the scope that started them. It utilizes a nursery-based task manager to track task lifecycles in a parent-child tree, preventing orphaned concurrent operations by requiring child tasks to be joined before their parent scope exits. The framework cover

Folly is a collection of high-performance C++ components designed as an extension to the C++ Standard Library for large-scale production environments. It provides specialized toolkits for memory management, concurrency, asynchronous workflows, and low-latency input and output operations. The project distinguishes itself through the provision of lock-free containers and bounded queues to minimize contention in multi-threaded applications, alongside a framework for managing deferred computations using futures and promises. It further offers specialized memory arenas and optimized implementation

Hazelcast is a distributed data platform that combines an in-memory data grid with a stream processing engine to support real-time analytics and event-driven applications. It functions as a partitioned, distributed key-value store that replicates data across cluster nodes to provide low-latency access and high availability. The platform also serves as a distributed SQL query engine, allowing users to execute standard SQL statements against both in-memory datasets and external data sources. What distinguishes Hazelcast is its use of a distributed consensus subsystem to maintain strongly consis

This project is an asynchronous library for the Python programming language designed to facilitate the development of automated agents and interactive applications on the Discord platform. It provides a comprehensive framework for building event-driven software that manages real-time communication, server resources, and user interactions through a structured interface. The library utilizes a non-blocking event loop to handle concurrent network operations, allowing developers to maintain persistent bidirectional connections via WebSockets. It features a declarative system for routing text-base

Quarkus is a Kubernetes-native Java framework designed for building high-performance, memory-efficient applications. It utilizes ahead-of-time native compilation to transform Java code into standalone, optimized binaries that eliminate the need for a virtual machine, enabling rapid startup and reduced memory consumption. By performing code augmentation during the build phase, it shifts heavy processing tasks away from runtime, ensuring that applications are optimized for cloud-native environments. The framework distinguishes itself through a unified approach to reactive and imperative program

This project provides a functional package manager and a reproducible build system designed to ensure identical build inputs always produce the same outputs. It serves as the foundation for a declarative Linux distribution where the entire system state is defined in a configuration file, enabling predictable deployments and full-system rollbacks. The system uses a deterministic functional language and a lazy-evaluation expression engine to manage software dependencies and isolate build environments. It distinguishes itself through a content-addressable store that allows multiple versions of s

F Prime is a component-based framework designed for the development and deployment of embedded and spaceflight software. It provides a modular architecture that decouples software logic from communication interfaces, allowing developers to define system structures through a domain-specific modeling language. This model-based approach enables automated code generation, ensuring consistency across complex system topologies while maintaining strict interface contracts between software modules. The framework distinguishes itself through its integrated build system and ground data operations suite

h2o-3 is a distributed machine learning platform and automated machine learning framework designed for training and deploying predictive models using distributed in-memory computing. It functions as a deep learning framework and a distributed model scoring engine, capable of operating as a Kubernetes ML cluster to process large datasets in parallel. The platform distinguishes itself through automated machine learning capabilities that automatically select the best algorithms and hyperparameters to optimize model performance. It provides specialized deep learning toolkits for tasks including i

Bun is a high-performance runtime environment designed to execute JavaScript and TypeScript applications with minimal latency and high throughput. Built on a native core implemented in Zig, it provides a unified execution engine that leverages JavaScriptCore for efficient memory management and low-latency startup. The project functions as an all-in-one toolchain, integrating a native bundler, transpiler, package manager, and test runner into a single command-line interface. What distinguishes Bun is its focus on native system integration and developer productivity. It features a high-performa

Sanic is an asynchronous Python web framework designed for building high-performance APIs and services. It operates as a production-ready ASGI web server, utilizing a non-blocking event loop to handle concurrent requests and maximize throughput. The framework is built to support scalable architectures, offering built-in worker process management to distribute traffic across available CPU cores. What distinguishes Sanic is its focus on modularity and developer-centric tooling. It features a blueprint-based system for organizing complex applications into pluggable components, alongside a robust

Embassy is an asynchronous framework for microcontrollers that provides a runtime for cooperative multitasking. It enables the execution of multiple concurrent tasks to maximize energy efficiency and CPU usage, utilizing an async executor that puts the processor to sleep when idle. The framework includes a comprehensive set of embedded components, featuring a hardware abstraction layer for peripherals like GPIO, SPI, I2C, and UART, alongside a TCP/IP network stack and a USB device stack. It also provides a Bluetooth Low Energy host stack for wireless communication and a bootloader framework t

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

Nano is a distributed application framework designed for building systems using an actor-based messaging model. It functions as a distributed actor framework that decouples components through asynchronous messaging to maintain state isolation across a server cluster. The system acts as a cluster message dispatcher and session-aware request router, tracking client state to route incoming messages to the specific agent holding the session data. It utilizes a distributed agent registry to coordinate the dispatching of messages between multiple application instances acting as agents. The framewo

FoundationDB is an ACID-compliant distributed transactional key-value store. It functions as a scalable database engine that ensures strict serializability and data consistency across a cluster of servers using a shared-nothing architecture. The system is distinguished by its multi-region replication capabilities, allowing data to be synchronized across different datacenters for high availability and disaster recovery. It utilizes optimistic concurrency control to manage distributed transactions and employs a majority-based coordination system to maintain cluster state. The platform provides

PPHC is a technical reference and educational resource for distributed systems engineering. It serves as a textbook and manual for designing high-concurrency architectures and scalable infrastructure. The project provides detailed guidance on distributed database engineering, covering data storage strategies such as B+ Trees and Log-Structured Merge-Trees. It includes material on distributed transaction management and the implementation of fault-tolerant systems using consensus algorithms and state synchronization. The resource covers a broad range of system design capabilities, including co

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

Iggy is a distributed message streaming platform and multi-protocol message broker that functions as a persistent distributed log store. It provides infrastructure for publishing and consuming binary messages using an append-only log, ensuring high availability and data consistency across nodes through Viewstamped Replication. The platform is distinguished by its specialized LLM streaming infrastructure, which uses a server protocol to connect large language models to streaming data and system controls. This includes standardized protocols for context management and data bridging via HTTP or

monoio is a high-performance asynchronous runtime and executor for Rust. It implements a thread-per-core concurrency model that pins tasks to specific CPU cores to eliminate synchronization overhead and data migration. The runtime leverages the io_uring interface to perform non-blocking system calls and reduce kernel-user mode memory copying. It utilizes a high-performance I/O driver and zero-copy TCP stream wrapping to manage data transfer via shared-memory buffers. The project provides capabilities for CPU core affinity management, low-latency system programming, and high-performance netwo

Doris is a distributed SQL data warehouse designed for high-performance analytical workloads and real-time data processing. It functions as a unified platform that integrates traditional relational warehousing with lakehouse query capabilities, allowing users to execute analytical operations directly against external data lakes without requiring data migration. The system distinguishes itself through a shared-nothing, massively parallel processing architecture that utilizes vectorized query execution and columnar storage to maintain sub-second latency. It supports dynamic schema evolution, en

Ceph is a unified, software-defined storage platform designed to provide object, block, and file storage services from a single distributed cluster. By decoupling data management from physical hardware, it enables elastic scaling across commodity hardware, allowing organizations to build large-scale storage infrastructure without reliance on proprietary vendor equipment. The system distinguishes itself through a shared-nothing, distributed architecture that utilizes deterministic hashing for data placement. This approach eliminates centralized metadata bottlenecks, allowing the cluster to sca