Article · Wikipedia archive · Last revised May 28, 2026

HAProxy

HAProxy is a free and open source software that provides a high availability load balancer and proxy for TCP and HTTP-based applications that spreads requests across multiple servers. It is written in C and has a reputation for being fast and efficient.

Last revised
May 28, 2026
Read time
≈ 3 min
Length
758 w
Citations
24
Source
Wikipedia ↗
HAProxy
Original authorWilly Tarreau
Initial releaseDecember 16, 2001 (2001-12-16)
Stable release
3.2.01 Edit this on Wikidata / 28 May 2025
Written inC
Operating systemLinux, FreeBSD, OpenBSD, Solaris (8/9/10), AIX (5.1–5.3), macOS, Cygwin
LicenseGNU General Public License Version 2
Websitewww.haproxy.org Edit this on Wikidata
Repository

HAProxy is a free and open source software that provides a high availability load balancer and proxy (forward proxy,2 reverse proxy) for TCP and HTTP-based applications that spreads requests across multiple servers.3 It is written in C4 and has a reputation for being fast and efficient (in terms of processor and memory usage).5

HAProxy is used by a number of high-profile websites including GoDaddy, GitHub, Bitbucket,6 Stack Overflow,7 Reddit, Slack,8 Speedtest.net, Tumblr, Twitter910 and Tuenti11 and is used in the OpsWorks product from Amazon Web Services.12

History

HAProxy was written in 200013 by Willy Tarreau,14 a core contributor to the Linux kernel,15 who still maintains the project.

In 2013, the company HAProxy Technologies, LLC was created. The company provides a commercial offering, HAProxy Enterprise and appliance-based application-delivery controllers named ALOHA.

Features

HAProxy has the following features:

HAProxy Community vs HAProxy Enterprise

HAProxy Enterprise Edition is an enterprise-class version of HAProxy that includes enterprise suite of add-ons, expert support, and professional services. It has some features backported from the HAProxy development branch.20

ALOHA

HAProxy Technologies’ ALOHA is a plug-and-play load-balancing appliance that can be deployed in any environment. ALOHA provides a graphical interface and a templating system that can be used to deploy and configure the appliance.21

Versions

HAProxy has had the following version releases:22

Version Release date End of life
Unsupported: 1.0 2001-12-16 2001-12-30
Unsupported: 1.1 2002-03-10 2006-01-29
Unsupported: 1.2 2003-11-09 2011-08-06
Unsupported: 1.3 2006-06-29 2016-03-14
Unsupported: 1.4 2010-02-26 2018-02-08
Unsupported: 1.5 2014-06-19 2020-01-10
Unsupported: 1.6 2015-10-13 2020-Q4
Unsupported: 1.7 2016-11-25 2021-Q4
Unsupported: 1.8 2017-11-26 2022-Q4
Unsupported: 1.9 2018-12-19 2020-Q2
Unsupported: 2.0 2019-06-16 2024-Q2
Unsupported: 2.1 2019-11-25 2021-Q1
Unsupported: 2.2 LTS 2020-07-07 2025-Q2
Unsupported: 2.3 2020-11-05 2022-Q1
Supported: 2.4 LTS 2021-05-14 2026-Q2 (critical fixes only)
Unsupported: 2.5 2021-11-23 2023-Q1
Supported: 2.6 LTS 2022-05-31 2027-Q2 (critical fixes only)
Unsupported: 2.7 2022-12-01 2024-Q1
Supported: 2.8 LTS 2023-05-31 2028-Q2
Unsupported: 2.9 2023-12-05 2025-Q1
Supported: 3.0 LTS 2024-05-29 2029-Q2
Unsupported: 3.1 2024-11-26 2026-Q1
Supported: 3.2 LTS 2025-05-28 2030-Q2
Latest version: 3.3 2025-11-26 2027-Q1
Future version: 3.4-dev → LTS 2026-Q2 2031-Q2
Legend:
Unsupported
Supported
Latest version
Preview version
Future version

Performance

Servers equipped with 6 to 8 cores generally achieve between 200,000 and 500,000 requests per second, and have no trouble saturating a 25 Gbit/s connection under Linux.23 64-core ARM servers were shown to reach 2 million requests per second and 100 Gbit/s.24

Similar software

See also

See also

References

References

  1. "Release 3.2.0". 28 May 2025. Retrieved 16 June 2025.
  2. "HAProxy as Forward Proxy".
  3. "Using HAProxy for MySQL failover and redundancy". Alexander Williams. 2009. Retrieved 19 February 2013.
  4. "HAProxy on Freecode". Retrieved 5 April 2013.
  5. Tsoukalos, M. "HAProxy: TCP load balancer". Linux Format. 2017;(224):76-79. Retrieved July 25, 2025.
  6. "The inner guts of Bitbucket". YouTube. 24 July 2014. Retrieved 26 February 2015.
  7. "What it takes to run Stack Overflow". Retrieved 22 November 2013.
  8. "All Hands on Deck". Slack Engineering. 29 June 2020. Retrieved 2020-07-07.
  9. "HAProxy: they use it!". Retrieved 5 April 2013.
  10. "List of sites using HAProxy". Archived from the original on 10 June 2013. Retrieved 5 April 2013.
  11. "Tuenti+WebRTC (Voip2day 2014)".
  12. "HAProxy layer - AWS Opsworks". Retrieved 5 April 2013.
  13. "HAProxy: design choices and history". Retrieved 5 April 2013.
  14. "Willy Tarreau: About me". Retrieved 5 April 2013.
  15. "LKML: Willy Tarreau: [ANNOUNCE] Linux 2.4.37.11". Retrieved 5 April 2013.
  16. Corbett, Daniel (2018-12-19). "HAProxy 1.9 Has Arrived". HAProxy Technologies. Retrieved 2019-01-22.
  17. Ramirez, Nick (2022-05-31). "Announcing HAProxy 2.6". HAProxy Technologies. Retrieved 2023-07-30.
  18. Mhedhbi, Moemen (2018-05-31). "Hitless Reloads / Hot Restarts with HAProxy!". HAProxy Technologies. Retrieved 2019-01-22.
  19. Ramirez, Nick (2019-01-16). "HAProxy 1.9.2 Adds gRPC Support". HAProxy Technologies. Retrieved 2019-01-22.
  20. "HAProxy Technologies Announces Improvements to Performance, Management, and Security for Enterprises" (Press release). 2 May 2018. Retrieved 23 Oct 2018.
  21. "ALOHA Hardware Appliance Application Delivery Controller". Retrieved 23 Oct 2018.
  22. "HAProxy". Retrieved 15 December 2022.
  23. haproxy.org#plat
  24. www.haproxy.com/blog/haproxy-forwards-over-2-million-http-requests-per-second-on-a-single-aws-arm-instance/
External links