Investigating the impact of HTTP3 on network latency for search

This post details an investigation into the impact of HTTP3 on network latency for Dropbox's search functionality. It describes an experiment conducted in collaboration with the Traffic team to compare HTTP2 and HTTP3 performance. The experiment involved setting up a test subdomain with a no-op API endpoint to isolate network latency. The methodology included cache warming, running parallel HTTP2 requests as a control, and then running parallel HTTP3 requests. Results showed significant latency reductions at higher percentiles (p90, p95) and for users in Asia, Europe, and North/Central America, particularly due to HTTP3's elimination of head-of-line blocking. The findings indicate that HTTP3 offers substantial benefits for users experiencing higher latencies and will inform a production rollout.