The Backend Engineering Show with Hussein Nasser Episode 121 - What happens when you type google.com into your browser address box and hit enter?
In this video I want to go through what really happens under the hood when you type google.com and you hit enter in a browser. This is inspired by alex’s github page below, it is a great detailed description of what happens. I did however add more details to certain areas and I removed some stuff like keyboard events and low level operating system like that. So if you are interested stay tuned!
https://github.com/alex/what-happens-when
5:30 HSTS https://youtu.be/kYhMnw4aJTw
19:30 tcp vs udp
24:42 tls
40:56 mimesniffing
Initial typing
- lookup for most visited sites or an actual search
Google.com Enter
- parse is it a url or search term? If search do a search if url visit website
Which protocol? which port ?
HSTS?
HTTPS
or HTTP?
DNS
cached?
Hosts?
DoH?
Lookup ?
TCP
ip / port ?
arp?
NAT?
proxy?
HTTP 1.1 ? More than one connection
TLS
version? ciphers? Alpn? SNI ? H2 ? H3? Quic?
GET / - ?
Headers compress
cookies?
binary stream?
HTML?
H2 push?
HTML Parse?
Make multiple requests css? JS? Multiple streams?
If H1 then pipeline?