What is netpoll?

Netpoll is a networking toolkit built in Go by ByteDance, the company behind TikTok. It is designed to make the behind-the-scenes communication between different parts of an app, specifically in microservice architectures, much faster and more efficient. Think of it as a high-speed postal system for software, optimized for situations where servers are constantly sending rapid-fire requests back and forth. To understand why this exists, it helps to know a common pain point. Go, the programming language it is written in, normally handles network connections by assigning a lightweight background task (called a goroutine) to every single connection. When a server handles thousands of connections at once, all that juggling creates overhead. Netpoll avoids this by using a non-blocking approach, meaning it can manage many connections without getting bogged down. It also includes a way to easily check if a connection is still alive, which prevents servers from wasting time trying to use broken links. This tool is built for developers creating high-performance backend systems, particularly those using Remote Procedure Call (RPC) patterns where software components talk to each other directly. For example, a video streaming app might have one service handling user logins and another fetching video recommendations. If millions of users are active at once, the chatter between those services can become a bottleneck. Netpoll ensures that bottleneck doesn't happen. ByteDance actually uses it as the foundation for their own open-source RPC and HTTP frameworks. The project makes a few deliberate tradeoffs. It focuses on TCP and Unix Domain Sockets on Linux and macOS, and the README explicitly notes that Windows is not supported. Features like TLS encryption and UDP support are on the roadmap but not yet available. By keeping the scope narrow, the project delivers a highly specialized, fine-tuned tool for heavy-duty server communication rather than a general-purpose networking library.