Open-source alternatives to Micro

Javalin is a lightweight web framework for Java and Kotlin designed for building REST APIs and web applications. It functions as an embedded Jetty web server, allowing applications to run as standalone processes without the need for an external servlet container. The project provides specialized frameworks for diverse communication patterns, including a REST API framework with automatic OpenAPI schema generation, a GraphQL API framework with query and mutation resolvers, and a WebSocket server for bidirectional real-time communication. It also includes a dedicated framework for pushing real-t

Micro is a minimalist Node.js web framework designed for creating lightweight, asynchronous HTTP services and JSON APIs. It serves as a low-footprint library for deploying asynchronous handlers focused on high request volumes and minimal overhead. The framework utilizes a functional request and response model, routing traffic to a single exported asynchronous function as the primary entry point. It specializes in processing incoming JSON requests and returning formatted responses with automated error handling. Core capabilities include request body parsing for JSON, plain text, and binary bu

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

Quart is an asynchronous Python web framework that implements the ASGI specification. It is used to build high-performance HTTP and WebSocket services, JSON REST APIs, and web applications using async and await syntax for non-blocking request handling. The framework supports persistent bidirectional communication via WebSocket API servers and enables the proactive delivery of assets through HTTP server push. It also includes a template engine for rendering dynamic HTML web pages and supports incremental request and response streaming to manage large payloads. General capabilities cover reque

Oatpp is a high-performance C++ web framework and API development kit used for building REST APIs and web services. It functions as an asynchronous HTTP server that utilizes coroutines to handle thousands of simultaneous connections without blocking threads. The toolkit includes a native C++ object-relational mapping layer for executing SQL queries and transforming database results into data objects. It also provides a WebSocket communication library for establishing full-duplex channels to support real-time data streaming and live media. The framework covers a broad range of capabilities, i

Martini is a web framework for the Go programming language that provides a toolkit for building web applications. It functions as a routing engine and an HTTP middleware pipeline to map network requests to specific handler functions. The framework is distinguished by its dependency injection system, which automatically resolves and provides requested service types as arguments to handler functions. This allows for the decoupling of business logic from infrastructure by matching requested types against a registry of available services. The project covers a broad range of web capabilities, inc

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

Feathers is a database-agnostic Node.js application framework designed for building scalable backend systems. It functions as a real-time API framework that provides a server implementation for both REST endpoints and WebSocket connections. The framework decouples application logic from the underlying database technology and communication protocols. This allows a single service to handle both HTTP and Socket requests while separating business logic from the specific data persistence layer. The system organizes data operations through a standardized service-based interface and utilizes hook-b

Express is a minimalist web server framework that provides a foundational runtime environment for building backend web APIs and applications. It operates through a central application object that orchestrates the entire request-response lifecycle, allowing developers to define routes, manage server settings, and process incoming HTTP traffic. The framework is defined by its middleware-based routing engine, which sequences request handlers and logic blocks to process traffic based on path patterns and HTTP methods. This architecture supports a highly modular approach, enabling the creation of

Erupt is a framework for building administrative interfaces, business intelligence layers, and visual workflow engines. It provides a multi-tenant admin panel and an LLM admin framework that automatically generates web-based management consoles and REST endpoints from backend class definitions. The project distinguishes itself by integrating AI agent orchestration, allowing administrators to manage server operations and execute backend logic through a conversational chat interface. It also features a BI semantic layer that maps raw warehouse data into business-oriented cubes for self-service

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

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

Vapor is a comprehensive server-side web framework designed for building scalable, high-performance applications and APIs in Swift. It provides a non-blocking, event-loop-based runtime that manages concurrent task processing, background job queues, and asynchronous request handling. The framework is built around a dependency injection container that manages the lifecycle and resolution of services, configurations, and database connections throughout the request pipeline. The framework distinguishes itself through a protocol-oriented design that emphasizes type safety across all layers of the

LoopBack Next is a Node.js API framework used for building REST and multi-protocol APIs. It functions as an OpenAPI server implementation that can either generate machine-readable specifications from code or produce implementation controllers and models from existing specifications. The framework distinguishes itself through a central dependency injection container and a repository-pattern data access layer. This architecture decouples application logic from component construction and persistent storage, allowing for a pluggable system where data sources and business logic are isolated throug

Strawberry is a type-safe GraphQL library for Python that enables the design of schemas using Python type annotations and dataclasses. It functions as an asynchronous GraphQL server and execution engine, providing a bridge to expose schemas across ASGI-compliant web frameworks such as FastAPI, Django, Flask, and Litestar. The project implements GraphQL Federation, allowing for the creation of distributed schemas and entities that merge into a unified supergraph across multiple services. It also includes a dedicated toolkit for the Relay specification, supporting global object identification a

Elysia is a high-performance TypeScript web framework designed for building type-safe backend services. It provides a modular, plugin-based architecture that allows developers to compose server logic, middleware, and validation schemas into scalable application instances. By leveraging native web standards, the framework ensures portability across diverse JavaScript runtimes, including Node.js, Deno, and various edge computing environments. The framework distinguishes itself through its focus on end-to-end type safety, automatically synchronizing request and response definitions between the s

Vendure is a Node.js e-commerce engine and headless commerce framework built with NestJS and TypeScript. It serves as a multi-channel commerce platform that manages product catalogs, orders, and customers via a strongly typed GraphQL API. The platform is distinguished by its highly extensible architecture, featuring a customizable administrative dashboard where developers can inject custom React components and entity views. It supports multi-channel commerce, allowing the isolation of products, currencies, and regional catalogs from a single unified backend. The engine covers a broad range o

TinyWebServer is a lightweight HTTP web server written in C++ for Linux. It is designed to handle HTTP requests and serve static content using low-level Linux system calls for network connection management. The server utilizes a state machine to parse GET and POST data from network sockets. It incorporates a MySQL database connection pool to manage reusable links and reduce the overhead of opening and closing sessions. The project covers static media streaming for images and video files, user authentication workflows for registration and login, and system activity logging via both synchronou

This is a streamlined Ruby on Rails framework designed for building lightweight backend services and JSON endpoints. It utilizes a model-view-controller architecture to separate data models and business logic from API responses, specifically omitting browser-centric views to reduce system overhead. The framework provides a system for rapidly generating models, controllers, and routes through JSON API scaffolding. It maps HTTP verbs to controllers to ensure consistent resource routing and data modeling for RESTful API backends. The project includes capabilities for HTTP request management, su

Swifter is a lightweight HTTP server engine and routing system written in the Swift programming language. It functions as a web server capable of handling network requests and delivering responses such as HTML and plain text. The project provides a Swift WebSocket server for establishing bidirectional real-time communication channels to exchange text and binary data. It also includes a static file server that maps URL paths to local directories for direct file system access. The engine manages HTTP request routing by mapping specific URL paths to handler functions for delivering dynamic cont

Pingora is a Rust-based framework for building high-performance network services, including HTTP reverse proxies, layer seven load balancers, and TLS termination proxies. It serves as an asynchronous network library designed to intercept and route HTTP, gRPC, and WebSocket traffic between clients and upstream backend servers. The project enables zero-downtime service updates by handing over listening sockets between processes during binary or configuration upgrades. It utilizes a programmable multi-phase pipeline to modify request and response bodies and headers, and it provides a pluggable T

This project is a comprehensive library of reference implementations and patterns for building web applications using the Go Fiber framework. It provides curated templates and implementation guides for creating REST APIs, web servers, and structured backend services. The repository serves as a practical resource for applying architectural patterns, including Clean and Hexagonal architectures, as well as port-and-adapter decoupling. It offers detailed examples for integrating common web features such as OAuth2 authentication, JWT verification, WebSockets for real-time communication, and server

Hapi is a configuration-driven web framework for building secure and scalable HTTP servers and APIs on the Node.js runtime. It functions as a REST API development framework and an enterprise server implementation focused on stability, security, and comprehensive input validation. The framework is built around a plugin-based architecture, allowing core functionality and custom logic to be organized into modular, registerable plugins. It serves as an HTTP request lifecycle manager, enabling the interception and modification of requests through pre-handlers and extensions before they reach the f

Warp is a Rust HTTP web framework designed for building high-performance web servers. It provides a system for managing request pipelines, implementing WebSocket servers for bidirectional communication, and serving static assets from the local filesystem. The framework is characterized by its use of type-safe request pipelines and routing. It utilizes a filter-based approach to extract and validate metadata from headers, query strings, and request bodies before they reach the application handler. Broad capability areas include HTTP API development, asynchronous task execution, and state-base

This project is a software engineering educational resource providing a collection of canonical system implementations. It serves as a library of computer science case studies and polyglot code examples designed to demonstrate architectural tradeoffs and design patterns through concise versions of fundamental software components. The repository focuses on studying the implementation of core concepts such as consensus algorithms, interpreters, and database engines. It provides minimal versions of complex systems to facilitate the analysis of language design, data structure implementation, and

body-parser is a Node.js HTTP request parser that converts incoming request bodies into structured JavaScript objects. It provides utilities to extract and process JSON, raw binary, plain text, and URL-encoded payloads for use in web servers. The project employs a middleware pattern to augment request objects, attaching parsed data directly to the request for use in subsequent route handlers. It uses content-type based dispatching to select the appropriate parsing logic based on the request headers. The tool manages data streams by consuming payloads in chunks and accumulating binary buffers

go-zero is a toolkit for building cloud-native distributed services in Go. It functions as a microservices framework that provides built-in support for RPC, web APIs, and service discovery. The project includes a microservices code generator that produces production-ready server and client boilerplate from API descriptions. This automation is supported by a domain-specific language and pattern libraries designed to ensure compatibility with AI assistants. The framework incorporates a resilience suite for distributed system reliability, utilizing adaptive circuit breakers, rate limiting, and