Open-source alternatives to Starlette

NanoHTTPD is a lightweight, embeddable HTTP server for Java applications. It allows developers to integrate web server capabilities directly into a Java project to handle incoming requests without requiring a standalone installation. The project provides specialized implementations for an HTTPS web server, a WebSocket server for bidirectional real-time communication, and a static file web server. These capabilities enable secure network traffic through SSL certificates and the delivery of local files with automatic MIME type detection. The server includes systems for request routing and hand

This project is a comprehensive sample library and implementation guide for ASP.NET Core. It provides a collection of practical examples and projects that demonstrate how to build web applications, RESTful APIs, and high-performance services. The repository focuses on a variety of architectural patterns, including the development of Minimal APIs, contract-first gRPC services, and real-time communication using WebSockets and Server-Sent Events. It includes detailed implementations for user identity and security, such as token-based authentication and CSRF protection. The codebase covers a bro

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

Crow is a C++ web framework for building HTTP servers, providing routing, a middleware pipeline, JSON serialization, and WebSocket support. It enables developers to define typed route handlers that extract URL parameters at compile time, return structured JSON responses, and manage real-time bidirectional communication. The framework distinguishes itself with compile-time route pattern parsing and typed argument binding, which eliminate runtime parsing overhead for URL parameters. Its event loop runs on Boost.Asio, and handler execution can be offloaded to a configurable thread pool to keep I

Oak is a cross-runtime HTTP middleware framework and web server designed to operate across Deno, Node.js, Bun, and Cloudflare Workers. It provides a unified system for building APIs and web servers using a sequential chain of middleware functions and a hierarchical routing engine that maps URL paths to handlers via a nested tree structure. The framework includes a runtime-agnostic serverless adapter that translates diverse cloud provider events into a standard request and response interface. It also features a dedicated WebSocket server implementation for bidirectional real-time communication

This is a header-only C++ library that provides implementations for HTTP clients, HTTP servers, and a WebSocket framework. It allows for the creation of network services and the consumption of remote APIs without requiring a separate compilation step or external binary linking. The project features backend-agnostic TLS integration for secure HTTPS and WSS communication and employs a thread-pool model to process concurrent requests. It distinguishes itself with a full-duplex WebSocket state-machine and a middleware-based request pipeline that supports regular-expression path routing. The libr

Hono is a lightweight web framework built on Web Standard APIs that executes across JavaScript runtimes including Cloudflare Workers, Deno, Bun, and Node.js.

Perfect is a server-side Swift framework designed for building high-performance web applications, REST APIs, and backend services. It provides an asynchronous HTTP server that handles web traffic through an event loop, alongside a web template engine for generating dynamic HTML pages. The project includes a WebSocket communication library for implementing bidirectional, real-time data exchange between clients and servers. It also provides a database connector to establish connections and exchange data between Swift applications and external database stores. The framework's capabilities cover

This is a full-stack web development framework for Node.js based on the model-view-controller architecture. It provides a comprehensive platform for building applications with an integrated dynamic view engine for HTML markup, a WebSocket communication server for bidirectional real-time messaging, and an embedded NoSQL database for persisting flexible data structures without external dependencies. The framework includes a background task processor that offloads computationally intensive operations to separate worker threads to maintain application responsiveness. It also features an internati

RoadRunner is a high-performance application server and process manager designed to serve PHP applications using a persistent worker model. It eliminates bootload overhead and initialization time by keeping application processes alive between requests, acting as a protocol-agnostic proxy that routes traffic to a pool of supervised workers. The server is built with a plugin-based modular architecture, allowing it to be extended with custom Go plugins and compiled into tailored binaries. It distinguishes itself by providing a unified execution model for a wide array of communication protocols,

Litestar is a high-performance Python ASGI web framework designed for building asynchronous APIs and web services. It functions as a type-safe toolkit that leverages Python type hints to provide automatic request validation and response serialization, while natively generating interactive API documentation based on the OpenAPI specification. The framework is distinguished by its integrated dependency injection system, which manages shared resources and resolves complex nested service chains directly within request handlers. It further organizes API development through class-based controllers

Robyn is a high-performance asynchronous web framework and server for Python that utilizes a Rust-powered runtime to execute code. It functions as an asynchronous Python web server designed to handle many concurrent requests efficiently through a multithreaded execution model. The project includes specialized capabilities for AI agent request routing, managing communication between agents and external tools. It also serves as a WebSocket communication server, maintaining persistent bidirectional channels for real-time data exchange. The framework covers a broad range of web infrastructure, i

This project is a high-performance PHP application server designed to keep applications resident in memory, eliminating the bootstrap overhead typically associated with each request. It functions as a multi-protocol network server capable of handling HTTP, WebSocket, TCP, and UDP traffic simultaneously within a single instance. The system is distinguished by an event-driven worker pool and a high-precision task scheduler that executes recurring background jobs at millisecond intervals. It utilizes a shared memory state store for high-speed data access across worker processes and incorporates

Werkzeug is a comprehensive library and toolkit for building WSGI-compliant web applications in Python. It provides the fundamental building blocks for web development, including an HTTP request and response toolkit, a rule-based URL routing engine, and a library for managing the overall web application lifecycle. The project is distinguished by its integrated development suite, which includes a WSGI development server featuring automatic code reloading and a PIN-protected interactive browser debugger for inspecting call stacks. It also includes a specialized WSGI test client that enables the

This project is a request router and web framework for the Go programming language. It provides a toolkit for matching incoming HTTP network requests to specific handler functions by evaluating criteria such as URL paths, request methods, headers, and hostnames. The framework distinguishes itself through its flexible matching capabilities, which include support for regular expressions and dynamic variable extraction from URL segments. It allows developers to organize routes into logical hierarchies, share common path prefixes, and maintain a central registry of named routes to facilitate prog

FastHTML is a full-stack Python web framework designed for building interactive web applications using pure Python. It functions as an HTMX integration framework and a Python HTML domain-specific language, allowing developers to generate HTML structures using native objects and functions instead of external templating files. The framework is distinguished by its native support for real-time bidirectional communication via WebSockets and Server-Sent Events, enabling server-side updates to be pushed to the browser without full page reloads. It further integrates identity management through OAut

This project is a full-stack web application framework and starter template designed for building complete web services in Python. It provides a structured foundation for developing applications that integrate server-side processing logic, persistent database storage, and frontend user interface delivery. The framework utilizes the model-view-controller architectural pattern to organize application logic into distinct layers for data management, request handling, and interface rendering. It incorporates an object-relational mapping library to simplify database interactions by translating tabl

Fasthttp is a high-performance networking framework for Go, designed to maximize throughput and minimize memory overhead in demanding web applications. It functions as a specialized HTTP server and client library that prioritizes efficient resource management, allowing developers to build scalable services capable of handling massive concurrent traffic with minimal garbage collection pressure. The library distinguishes itself through a focus on zero-allocation processing and low-level optimization. It achieves this by recycling temporary request and response objects through managed pools and

Revel is a full-stack web framework and toolkit for building applications with the Go language. It implements a model-view-controller architecture to separate business logic from user interface rendering, providing a comprehensive system for routing, parameter binding, and session management. The project distinguishes itself with a high-productivity development environment featuring automatic code compilation and hot-reloading, which refreshes the application state and templates upon file changes without requiring manual restarts. It also employs reflection-based parameter binding to automati

libhv is a high-performance C/C++ network library and event-driven I/O framework used to build TCP, UDP, SSL, HTTP, WebSocket, and MQTT clients and servers. It provides a non-blocking event loop for managing network sockets, timers, and system signals across multiple threads. The project is distinguished by its integrated support for specialized network roles, including a full HTTP web server with RESTful routing and middleware, an MQTT messaging client for IoT communication, and the ability to implement SOCKS5 and HTTP proxies. It also features a reliable UDP implementation to ensure ordered

This is a self-hosted WebSocket server for Laravel applications designed to provide real-time communication and replace third-party managed messaging services. It provides a server-side PHP implementation of the WebSocket standard, enabling full-duplex communication between clients and servers. The project implements a Pusher-compatible protocol to integrate with existing frontend client libraries. It includes a dedicated debug dashboard for monitoring active connections, tracking network traffic, and analyzing real-time server performance. The system supports Laravel event broadcasting and

This is a header-only C++ library and asynchronous network framework used to implement WebSocket clients and servers. It provides a full implementation of the WebSocket protocol, including handshakes, subprotocol negotiation, and frame parsing. The framework is distinguished by a policy-based transport layer and template-driven protocol negotiation, allowing the underlying network implementation to be swapped between raw buffers, streams, or custom policies. It supports per-message deflate compression to reduce data transmission volume and integrates Transport Layer Security for encrypted bid

This is a high-performance C++ HTTP web server designed for delivering static content. It operates as an asynchronous event loop server that combines IO multiplexing with worker thread pools to handle concurrent requests without blocking. The server specializes in TCP connection management, featuring keep-alive sessions, request pipelining, and timer-based timeout tracking for idle sockets. To ensure high throughput, it utilizes double-buffered asynchronous logging and background threads to prevent disk I/O latency from impacting network traffic. The system covers broad capability areas incl

Falcon is a minimalist Python web API framework and high-performance microservices framework. It serves as a resource-oriented API toolkit designed for building RESTful APIs and data plane services that prioritize low overhead, reliability, and scale. The framework implements an ASGI web server interface to handle both synchronous and asynchronous HTTP requests and WebSockets. It features a dedicated HTTP middleware system for intercepting network traffic and executing shared processing logic across multiple API endpoints. Its capability surface covers resource-based routing, HTTP specificat

Uvicorn is an ASGI web application host designed for asynchronous Python web development. It serves applications through a standardized asynchronous server gateway interface to handle non-blocking network traffic and high-concurrency requests. The server manages both HTTP and WebSocket traffic, including the handshaking process required to establish persistent, full-duplex communication channels for real-time data exchange. For development workflows, the project includes a hot-reload mechanism that monitors the filesystem for source code changes and automatically restarts the server process.

Sanic is a Python ASGI web framework and asynchronous HTTP server. It is designed to build high-performance web applications and servers that handle concurrent requests using non-blocking logic. The framework implements the Asynchronous Server Gateway Interface standard, allowing applications to be deployed across various ASGI-compatible servers. It utilizes an asyncio-based event loop and integrates a Cython-based runtime wrapper around libuv to manage I/O operations. The system manages traffic through route-based request dispatching and a middleware-based request pipeline. These components

Hyperf is a high-performance PHP coroutine framework designed for building microservices and middleware. It utilizes non-blocking coroutines to handle high concurrency and low-latency request processing, providing a foundation for scalable distributed systems. The framework is distinguished by an aspect-oriented programming based dependency injector that enables pluggable components and meta-programming. It includes a coroutine-optimized object-relational mapper with integrated model caching and an orchestration toolkit for microservice governance, featuring service discovery, circuit breaker