HAProxy is a high-performance, open-source load balancer and reverse proxy for TCP and HTTP applications. Users can make use of HAProxy to improve the performance of websites and applications by distributing their workloads. Performance improvements include minimized response times and increased throughput. HAProxy is used in high traffic services such as GitHub and Twitter.  

Load balancers can be used to distribute workloads across computers, networks, disk drives or CPU’s. HAProxy, included in many distributions of Linux, is one of the leading standards in software load balancing.

Though HAProxy is open source, a commercial option is available through HAProxy Technologies, called HAProxy Enterprise. HAProxy Enterprise includes an enterprise suite of add-ons, expert support, and professional services.

HAProxy Load Balancing
This image shows what load balancing in HAProxy looks like


HAProxy features include services such as:

  • Layer 4 and 7 load balancing (TCP and HTTP respectively)
  • Protocol support for HTTP, HTTP/2, gRPC, FastCGI
  • SSL/TLS termination
  • Dynamic SSL certificate storage
  • Content switching and inspection
  • Transparent proxying
  • Detailed logging
  • CLI for server management
  • HTTP authentication
  • Multithreading
  • URL rewriting
  • Advanced health checking
  • Rate limiting

The content switching feature will allow users to select server pools on request. Additionally, setting up a transparent proxy will allow users to connect to a server directly with a client IP address. Content inspections will allow users to block any unexpected protocols. Users can use its detailed logging to view real-time request data. The CLI will allow users to make changes such as turning on or off a server. HAProxy is also scalable to connect to thousands of back-ends.


HAProxy is considered to be secure by its users, having very few vulnerabilities over the years. It contains features that limit the attack surface in case of a security issue, such as isolating itself using chroot, dropping to a non-privileged user/group upon startup, and avoiding disk access after initialization. HAProxy can also be used in areas to make other systems more secure. For example, HAProxy can inspect traffic and monitor a client's behavior over a series of requests and then block the client if they seem malicious. Users can configure access control lists that define policies for when to allow access based on metadata found within a request. It also allows rate limiting and IP blacklisting/whitelisting.

This was last updated in September 2020

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