HAProxy

A reliable, high-performance TCP/HTTP load balancer.

HAProxy is a fast layer-4 and layer-7 load balancer often deployed in front of large web backends. It speaks TCP and HTTP, with rich support for sticky sessions, ACL-based routing, content switching, rate limiting, health checks, slow-start behaviour for new servers, and connection draining for maintenance windows. HAProxy can also act as a reverse proxy with TLS termination, HTTP/2, and HTTP/3.

The event-driven architecture lets a single instance handle hundreds of thousands of concurrent connections on commodity hardware. The configuration language is unusually expressive — ACLs that combine source IP, header values, URL paths, cookies, and more — and the stats page provides a real-time view of backend health.

Willy Tarreau started HAProxy in 2000 and continues as the lead maintainer. The open-source community version is GPL-2.0; HAProxy Technologies, the company, sells HAProxy Enterprise with additional features. HAProxy is widely deployed in front of Twitter (X), GitHub, Airbnb, Reddit, Stack Overflow, and many other large internet services.

License: GPL-2.0-or-later

Category: Networking

Website: https://www.haproxy.org/

Install

Debian/Ubuntu: sudo apt install haproxy
Fedora/RHEL:   sudo dnf install haproxy
Arch:          sudo pacman -S haproxy

Authors

Willy Tarreau (creator)
HAProxy Technologies and contributors

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