Tencent/libco

Health v2 · maintenance only

Flags: no_license

Adoption not part of the score

8687 stars · 2116 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-29, confidence not recorded

libco is a C/C++ coroutine library widely used in WeChat's back-end services since 2013, running on tens of thousands of machines. It transforms synchronous back-end services into coroutine-based services with minimal code changes, offering socket hooks for transparent asynchronous execution and a copy-stack mode supporting tens of millions of TCP connections.

Use cases

• convert synchronous backend services to coroutine-based services for higher concurrency
• write asynchronous network code in a synchronous style using socket hooks
• build back-end services supporting tens of millions of TCP connections
• create coroutines with co_create/co_resume/co_yield for fine-grained control
• hook third-party libraries like mysqlclient, ssl, and gethostbyname for async execution
• build lightweight web/CGI services on top of the built-in epoll/kqueue network framework

When to choose

• you need massive concurrency in C/C++ back-end services without rewriting logic
• you want synchronous-style code that executes asynchronously via socket hooks
• you need proven, production-grade coroutine support at extreme scale
• you want pthread-like coroutine APIs with minimal learning curve

When to avoid

• you work in a language with native async/await or goroutines
• your project targets Windows or platforms without epoll/kqueue support
• you need a full-featured networking framework rather than a coroutine primitive
• you require a permissive license - the license is not a standard open-source one

Facets

library · maturity stable

concurrency http-server networking middleware backend developer-tools microservices cpp c coroutines async socket-hook epoll kqueue copy-stack wechat high-concurrency real-time linux macos

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