# uWebSockets — Simple Secure High-Performance WebSocket and HTTP Server

> A C++ library for building extremely fast WebSocket and HTTP servers, powering some of the largest real-time applications on the internet.

## Install

Save in your project root:

# uWebSockets — Simple Secure High-Performance WebSocket and HTTP Server

## Quick Use
```bash
# C++ (vcpkg)
vcpkg install uwebsockets
# Node.js binding (uWebSockets.js)
npm install uWebSockets.js
```

## Introduction
uWebSockets is a C++ library that implements HTTP and WebSocket protocols with a focus on raw throughput and low memory usage. Its Node.js binding, uWebSockets.js, serves as a drop-in high-performance alternative for applications that need to handle millions of concurrent connections.

## What uWebSockets Does
- Provides HTTP/1.1 and WebSocket server implementations in optimized C++
- Delivers throughput that can exceed 1 million messages per second on a single core
- Offers a Node.js binding (uWebSockets.js) with a familiar API for JS developers
- Supports TLS via OpenSSL or BoringSSL for encrypted connections
- Handles pub/sub messaging patterns natively for broadcast workloads

## Architecture Overview
uWebSockets is built on top of uSockets, a minimal event-loop library written in C. The architecture avoids heap allocations on the hot path and uses epoll/kqueue for non-blocking I/O. WebSocket frames are parsed with zero-copy techniques. The Node.js binding wraps the C++ core via N-API, giving JavaScript applications near-native performance without requiring a full C++ build chain.

## Self-Hosting & Configuration
- For C++ projects, install via vcpkg or include as a header-only library
- For Node.js, install the prebuilt binary: `npm install uWebSockets.js`
- Configure listen options (port, host, SSL certs) when calling the `.listen()` method
- Set backpressure limits per WebSocket to control memory usage under load
- Deploy behind a reverse proxy (Nginx, Caddy) or use its built-in TLS support directly

## Key Features
- One of the fastest HTTP and WebSocket implementations available in any language
- Memory footprint measured in bytes per connection, not kilobytes
- Built-in pub/sub for topic-based broadcasting without external message brokers
- Graceful shutdown and per-socket backpressure management
- Standards-compliant with Autobahn test suite passing

## Comparison with Similar Tools
- **ws (Node.js)** — pure JS WebSocket library; uWebSockets.js is 10-50x faster
- **Socket.IO** — higher-level with fallbacks and rooms; uWebSockets focuses on raw protocol speed
- **Boost.Beast** — C++ HTTP/WebSocket on Boost.Asio; uWebSockets has a simpler API and lower overhead
- **Bun** — uses a fork of uWebSockets internally for its built-in server

## FAQ
**Q: Is uWebSockets.js a drop-in replacement for ws?**
A: The API differs slightly, but migration is straightforward. Most patterns map directly.

**Q: Does it support HTTP/2?**
A: Currently it supports HTTP/1.1 and WebSocket. HTTP/2 is not implemented.

**Q: Can I use it in production?**
A: Yes. It powers several large-scale real-time applications in production today.

**Q: What platforms are supported?**
A: Linux, macOS, and Windows. The Node.js binding ships prebuilt binaries for all three.

## Sources
- https://github.com/uNetworking/uWebSockets
- https://github.com/uNetworking/uWebSockets.js

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Source: https://tokrepo.com/en/workflows/asset-ca6f420b
Author: AI Open Source