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-svc9,917,803
Percentage of websites that use alt-svc header9.82%
Total discovered header values440
Header uses directivesYes
Header values are unique or randomNo
Most popular in the country US

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

DirectiveShareWebsites countUnique Values
ma99.32%9,850,48811
quic37.65%3,733,61721
v37.64%3,733,1288
h3-q04637.25%3,694,34612
h3-q04337.25%3,693,95312
h3-254.99%495,2506
clear0.61%60,8281
h3-240.46%45,3302
h2<0.1%7539
persist<0.1%3061
h3-q048<0.1%1852
h3-q049<0.1%972

Distribution by websites popularity

alt-svc detection in the top websites by popularity

Top 10k sites2,029 websites
Top 100k sites19,778 websites
Top 1m sites165,632 websites

Websites utilizing alt-svc

List of websites that use alt-svc header

DomainCountryRankContacts
fonts.googleapis.com US1
facebook.com US2
www.facebook.com US2
google.com US3
www.google.com US3
youtube.com US6
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 valueValue prevalence
h3=":443"; ma=86400, h3-29=":443"; ma=8640057.67%
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"24.85%
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="46,43"6.47%
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=25920004.90%
h3=":443"; ma=86400, h3-29=":443"; ma=86400, h3-28=":443"; ma=86400, h3-27=":443"; ma=864002.06%
h3=":443";ma=86400,h3-29=":443";ma=86400,h3-27=":443";ma=864001.35%
clear0.61%
h3=":443"; ma=2592000,h3-29=":443"; ma=25920000.48%
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"0.33%
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=25920000.28%
quic=":443"; ma=2592000; v="35,39,43,44"0.25%
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=25920000.10%
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=25920000.08%
quic=":443"; ma=2592000; v="39,43,46", h3-22=":443"; ma=25920000.07%
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=25920000.05%
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=25920000.05%
h3-Q050=":443"; ma=93600,quic=":443"; ma=93600; v="46,43"0.04%
h3=":443"; ma=86400,h3-29=":443"; ma=864000.04%
h3-29=":443"0.04%
h3-23=":443"; ma=25920000.04%