HTTP/3 explained

This book effort was started in March 2018. The plan is to document HTTP/3 andits underlying protocol: QUIC. Why, how they work, protocol details, theimplementations and more.

The book is entirely free and is meant to be a collaborative effortinvolving anyone and everyone who wants to help out.


A reader of this book is presumed to have a basic understanding of TCP/IPnetworking, the fundamentals of HTTP and the web. For further insights andspecifics about HTTP/2 we recommend first reading up the details in http2explained.


This book is created and the work is started by DanielStenberg. Daniel is the founder and lead developerof curl, the world’s most widely used HTTP clientsoftware. Daniel has worked with and on HTTP and internet protocols for overtwo decades and is the author of http2explained.


The home page for this book is found

Help out

If you find mistakes, omissions, errors or blatant lies in this document,please send us a refreshed version of the affected paragraph and we will makeamended versions. We will give proper credits to everyone who helps out. Ihope to make this document better over time.

Preferably, you submit errorsor pull requests on the book’sgithub page.


This document and all its contents are licensed under the Creative CommonsAttribution 4.0 license.