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 8,985,044
Percentage of websites that use alt-svc header 9.07%
Total discovered header values 399
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 99.02% 8,896,828 15
quic 33.76% 3,033,077 34
v 33.75% 3,032,603 11
h3-q046 33.24% 2,987,001 14
h3-q043 33.24% 2,986,572 14
h3-25 13.08% 1,174,822 10
clear 0.93% 83,199 2
h3-24 0.77% 69,570 2
h2 <0.1% 761 26
h3-q048 <0.1% 198 3
persist <0.1% 154 1
h3-q049 <0.1% 106 3

Distribution by websites popularity

alt-svc detection in the top websites by popularity

Top 10k sites 1,797 websites
Top 100k sites 18,142 websites
Top 1m sites 150,185 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 Ireland 2
www.facebook.com Ireland 2
google.com United States of America 3
www.google.com United States of America 3
youtube.com United States of America 6
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 41.40%
h3=":443"; ma=86400, h3-29=":443"; ma=86400, h3-28=":443"; ma=86400, h3-27=":443"; ma=86400 22.98%
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" 17.16%
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 12.76%
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" 1.37%
clear 0.92%
h3=":443"; ma=2592000,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" 0.82%
h3=":443";ma=86400,h3-29=":443";ma=86400,h3-27=":443";ma=86400 0.74%
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 0.32%
quic=":443"; ma=2592000; v="35,39,43,44" 0.32%
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 0.28%
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 0.17%
quic=":443"; ma=2592000; v="39,43,46", h3-22=":443"; ma=2592000 0.10%
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 0.06%
h3-29=":443" 0.05%
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 0.05%
h3-29=":443"; ma=3600,h3-27=":443"; ma=3600 0.05%
h3-Q050=":443"; ma=93600,quic=":443"; ma=93600; v="46,43" 0.05%
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" 0.05%
h3-Q050=":443"; ma=2592000, h3-Q046=":443"; ma=2592000, h3-Q043=":443"; ma=2592000, quic=":443"; ma=2592000; v="43,46" 0.04%