William Lallemand
Lead Developer at HAProxy Technologies
Paris, Ile-de-France
Summary
🤩
Rockstar🎓
Top SchoolWilliam Lallemand is a Lead Developer at HAProxy Technologies with 16 years of expertise in C, systems, networking and kernel-level work, specializing in HAProxy and high-performance load balancing. He has driven HAPEE development and master/worker SSL certificate handling improvements, and contributed hot certificate reload features to the widely used acme.sh project to enable zero-reload HAProxy deployments. His background includes porting Linux kernel patches and building toolchains at Exceliance, giving him deep operational and low-level systems experience beyond typical application engineering. Based in Paris, he blends hands-on backend code changes with DevOps pragmatism, making him particularly strong at bridging protocol-level implementation and production deployment.
15 years of coding experience
6 years of employment as a software developer
Epitech
Stackoverflow
1reputation
0reached
0answers
0questions
Github Skills (24)
ssl10
tls1210
scripting10
api-client10
load-balancing10
c-programming10
acme10
tls1310
network-programming10
script10
sh10
shell10
haproxy10
deployment-automation10
bash9
Programming languages (10)
Github contributions (5)
haproxy/haproxy
Feb 2019 - Mar 2025
HAProxy Load Balancer's development branch (mirror of git.haproxy.org)
Role in this project:
Back-end Developer
Back-end DeveloperContributions:2 branches, 717 comments, 140 issues in 6 years 2 months
Contributions summary:William primarily focused on back-end development tasks, with a strong emphasis on modifying and enhancing the HAProxy codebase. Their contributions included implementing new features, addressing bugs, and improving the overall functionality of the master worker mode. They introduced and modified several code sections related to SSL certificate handling.
proxycachingddos-mitigationhttp2ipv6
acmesh-official/acme.sh
Apr 2023 - Mar 2025
A pure Unix shell script implementing ACME client protocol
Role in this project:DevOps Engineer
DevOps EngineerContributions:3 reviews, 2 PRs, 24 comments in 1 year 11 months
Contributions summary:William focused on enhancing the deployment process within the `acme.sh` project, specifically for HAProxy integration. They implemented features for hot certificate updates using the HAProxy stats socket or master CLI, eliminating the need for service reloading. The contributions include enabling new certificate additions, employing the HAProxy master CLI, and adapting the deployment script for wildcard domain names to improve certificate management.
unixzerosslfreebsdshell-scriptshell
Find and Hire Top DevelopersWe’ve analyzed the programming source code of over 60 million software developers on GitHub and scored them by 50,000 skills. Sign-up on Prog,AI to search for software developers.