alt-svc

HTTP response header

The Alt-Svc header is used to list alternate ways to reach this website

Header usage statistics

alt-svc response header information and usage statistics.

Websites using header alt-svc 4,796,666
Percentage of websites that use alt-svc header 8.94%
Total discovered header values 250
Header uses directives Yes
Header values are unique or random No
Most popular in the country United States of America

alt-svc Directives (12 total)

  • clear
  • h2
  • h3-24
  • h3-25
  • h3-q043
  • h3-q046
  • h3-q048
  • h3-q049
  • ma
  • persist
  • quic
  • v

alt-svc Directives

alt-svc directives value information and usage statistics

Directive Share Websites count Unique Values
ma 36.09% 1,731,054 8
quic 14.22% 682,003 28
v 14.22% 681,997 11
h3-q046 13.96% 669,760 11
h3-q043 13.96% 669,699 11
h3-25 9.48% 454,946 10
h3-24 0.34% 16,371 1
clear 0.30% 14,212 1
h2 <0.1% 100 9
h3-q048 <0.1% 43 2
persist <0.1% 24 1
h3-q049 <0.1% 23 2

Distribution by websites popularity

alt-svc detection in the top websites by popularity

Top 10k sites 2,033 websites
Top 100k sites 26,814 websites
Top 1m sites 141,829 websites

Websites utilizing alt-svc

List of websites that use alt-svc header

Domain Country Rank Contacts
fonts.googleapis.com United States of America 1
facebook.com United States of America 2
www.facebook.com United States of America 2
youtube.com United States of America 4
www.youtube.com United States of America 4
google.com United States of America 5
See full domain list
Flat price per the report, subscription is not required.

Geographical Distribution

Header usage distribution by websites across the globe.






Common header values

List of top common alt-svc header values

Header value Value prevalence
h3-27=":443"; ma=86400, h3-28=":443"; ma=86400, h3-29=":443"; ma=86400, h3=":443"; ma=86400 58.69%
quic=":443"; ma=2592000; v="43,46", h3-Q043=":443"; ma=2592000, h3-Q046=":443"; ma=2592000, h3-Q050=":443"; ma=2592000, h3-25=":443"; ma=2592000, h3-27=":443"; ma=2592000 25.46%
h3-34=":443"; ma=2592000, h3-29=":443"; ma=2592000, h3-27=":443"; ma=2592000, h3-Q050=":443"; ma=2592000, h3-Q046=":443"; ma=2592000, h3-Q043=":443"; ma=2592000, quic=":443"; ma=2592000; v="43,46" 7.09%
h3-29=":443"; ma=2592000,h3-T051=":443"; ma=2592000,h3-Q050=":443"; ma=2592000,h3-Q046=":443"; ma=2592000,h3-Q043=":443"; ma=2592000,quic=":443"; ma=2592000; v="46,43" 3.66%
h3-27=":443"; ma=86400, h3-28=":443"; ma=86400, h3-29=":443"; ma=86400 1.37%
clear 0.83%
h3=":443"; ma=2592000, h3-29=":443"; ma=2592000, h3-Q050=":443"; ma=2592000, h3-Q046=":443"; ma=2592000, h3-Q043=":443"; ma=2592000, quic=":443"; ma=2592000; v="43,46" 0.64%
quic=":443"; ma=2592000; v="35,39,43,44" 0.45%
quic=":443"; ma=2592000; v="43,46", h3-Q043=":443"; ma=2592000, h3-Q046=":443"; ma=2592000, h3-Q050=":443"; ma=2592000, h3-24=":443"; ma=2592000, h3-25=":443"; ma=2592000 0.40%
quic=":443"; ma=2592000; v="39,43,46", h3-Q039=":443"; ma=2592000, h3-Q043=":443"; ma=2592000, h3-Q046=":443"; ma=2592000, h3-23=":443"; ma=2592000, h3-24=":443"; ma=2592000 0.36%
quic=":443"; ma=2592000; v="39,43,46,50", h3-Q039=":443"; ma=2592000, h3-Q043=":443"; ma=2592000, h3-Q046=":443"; ma=2592000, h3-Q050=":443"; ma=2592000, h3-23=":443"; ma=2592000, h3-24=":443"; ma=2592000 0.18%
quic=":443"; ma=2592000; v="39,43,46", h3-22=":443"; ma=2592000 0.17%
h3-34=":443"; ma=2592000, h3-29=":443"; ma=2592000, h3-Q050=":443"; ma=2592000, h3-Q046=":443"; ma=2592000, h3-Q043=":443"; ma=2592000, quic=":443"; ma=2592000; v="43,46" 0.13%
quic=":443"; ma=2592000; v="39,43,46", h3-Q039=":443"; ma=2592000, h3-Q043=":443"; ma=2592000, h3-Q046=":443"; ma=2592000, h3-22=":443"; ma=2592000 0.08%
quic=":443"; ma=2592000; v="39,43,46", h3-Q039=":443"; ma=2592000, h3-Q043=":443"; ma=2592000, h3-Q046=":443"; ma=2592000, h3-23=":443"; ma=2592000 0.06%
quic=":443"; ma=2592000; v="35,37,38,39" 0.05%
h3-Q050=":443"; ma=93600,quic=":443"; ma=93600; v="46,43" 0.04%
h3-29=":443"; ma=3600,h3-27=":443"; ma=3600 0.04%
h3-29=":443" 0.04%
quic=":8081"; ma=2592000; v="43,46", h3-Q043=":8081"; ma=2592000, h3-Q046=":8081"; ma=2592000, h3-Q050=":8081"; ma=2592000, h3-25=":8081"; ma=2592000, h3-27=":8081"; ma=2592000 0.04%