HTTP response header

The Upgrade header field is an HTTP header field introduced in HTTP/1.1. In the exchange the client begins by making a cleartext request which is later upgraded to a newer HTTP protocol version or switched to a different protocol.

Header usage statistics

Upgrade response header information and usage statistics.

Websites using header Upgrade 838,374
Percentage of websites that use Upgrade header 7.81%
Total discovered header values 65
Header uses directives No
Header values are unique or random No
Most popular in the country United States of America

Connected technologies

Technologies that utilize the header

HTTP/2, category Miscellaneous, total 838,346 websites

Distribution by websites popularity

Upgrade detection in the top websites by popularity

Top 10k sites 265 websites
Top 100k sites 7,230 websites
Top 1m sites 91,882 websites

Websites utilizing Upgrade

List of websites that use Upgrade header

Domain Country Rank Contacts
gmpg.org Canada 11
www.ncbi.nlm.nih.gov United States of America 72
searchengineland.com United States of America 322
caniuse.com United States of America 636
vizeo.net France 901
www.vizeo.net France 901
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Geographical Distribution

Header usage distribution by websites across the globe.

Common header values

List of top common Upgrade header values

Header value Value prevalence
h2,h2c 74.69%
h2 24.46%
h2c 0.68%
h2c,h2 0.12%
h2,http:/1.1 0.03%
h2,HTTP,1.1 0.00%
h2,http1.1 0.00%
h2,hc2 0.00%
http:/1.1 0.00%
h2,http/1/1 0.00%
h2 h2c http/1.1 0.00%
h2,http 0.00%
h2,h2c,HTTP/1.1 0.00%
HTTP/1.1 0.00%
h2,h2c,http:/1.1 0.00%
h2,h2c,h2-14 0.00%
h2,HTTP/1.1 0.00%
h2,h2c,http/1.1​ 0.00%
h2,,h2c, 0.00%
h2,https/1.1 0.00%