Processing Billions of Web Requests Per Day: A Journey From Hardware Load Balancers to HAProxy at DoubleVerify

DoubleVerify authenticates the quality of digital media for the world's largest brands. We use HAProxy to accomplish our goals of processing billions of requests daily, increasing and decreasing load balancer pools without affecting customers, and avoiding downtime during upgrades and maintenance periods. We will share our criteria we used when we set out to move from hardware to software load balancers, how we arrived at the decision to use HAProxy, and the results we've seen before and afterwards.