"With HTTP/1.1 pipelining, you can't reliably start sending the second request until the first response is complete." In the example, all 30 requests were sent

"With HTTP/1.1 pipelining, you can't reliably start sending the second request until the first response is complete." In the example, all 30 requests were sent at the same time. openssl did not wait for any responses. This example can be repeated again and again and every time, all the responses are received, in order. It is reliable. Not sure who "you" refers to in the above statement, however if it applies to me then that statement is incorrect. I have been using HTTP/1.1 pipelining outside the browser for decades. HTTP/1.1 was written for HTTP clients. Browsers are just one type of client, not the only type. More than half the traffic on the internet is initiated by non-interactive clients. Besides headless, that excludes browsers. From RFC 2616: user agent The client which initiates a request. These are often browsers, editors, spiders (web-traversing robots), or other end user tools.