Protocols

System design interviews rarely test you on protocol trivia. What they do test is whether you know which tool fits which problem — and can say why in one or two sentences. This article covers the protocols that come up most often, with just enough depth to sound competent, not academic.

1. HTTP / HTTPS — The Default

HTTP is the baseline for almost everything: REST APIs, browser traffic, service-to-service calls over the internet. A few things worth being able to say out loud: