X-Clacks-Overhead

X-Clacks-Overhead is a non-standard HTTP header used to transmit tribute messages within server responses.

Sites using it: 65

Usage over time

Trend data starts with the first full crawl. We take a snapshot of every technology's usage at the end of each monthly crawl cycle, so the first point appears once the current cycle completes and the trend line after the second.

Market share

Miscellaneous0.1%

Share of indexed sites in the category that use X-Clacks-Overhead.

Compare with

Frequently paired with

Share of sites using X-Clacks-Overhead that also use each of these, from a sample of up to 5,000 sites.

65 sites use X-Clacks-Overhead

Showing the top 50. Filter and browse all sites

mozilla.orgInternet for people, not profit — Mozilla Globalsince 28 Sept 2026
ubuntu.comEnterprise Open Source and Linux | Ubuntusince 28 Sept 2026
debian.orgDebian -- The Universal Operating Systemsince 28 Sept 2026
mozilla.comGet Firefox for desktop and mobile — Firefox.comsince 28 Sept 2026
firefox.comGet Firefox for desktop and mobile — Firefox.comsince 28 Sept 2026
stackexchange.comHot Questions - Stack Exchangesince 28 Sept 2026
imgsrc.ruUnlimited photo hosting @iMGSRC.RUsince 28 Sept 2026
canonical.comTrusted open source for enterprises | Canonicalsince 28 Sept 2026
snapcraft.ioSnapcraft - Snaps are universal Linux packagessince 28 Sept 2026
gameloft.comGameloft Official: We create gaming experiencessince 28 Sept 2026
raspberrypi.orgTeach, learn, and make with the Raspberry Pi Foundationsince 28 Sept 2026
marksandspencer.comM&S | Marks & Spencer | Fashion, Home, Beauty, Food & Giftssince 28 Sept 2026
raspberrypi.comRaspberry Pisince 28 Sept 2026
boingboing.netBoing Boing - A Directory of Mostly Wonderful Thingssince 28 Sept 2026
depop.comDepop - buy, sell, discover unique fashionsince 28 Sept 2026
pixeldrain.comCloud storage and data transfer services ~ pixeldrainsince 28 Sept 2026
inkscape.orgInkscape - Draw Freely. | Inkscapesince 28 Sept 2026
superuser.comSuper Usersince 28 Sept 2026
taz.detaz.de | taz.desince 28 Sept 2026
askubuntu.comAsk Ubuntusince 28 Sept 2026
questionablequesting.comQuestionable Questingsince 28 Sept 2026
dnevno.hrDnevno.hr - Dnevno.hr - Multimedijski novinarski portal. Mi smo oni koji se usude objaviti.since 28 Sept 2026
34sp.comUK website hosting and domain name registration servicessince 28 Sept 2026
sitezoogle.comEffective websites made easy - Sitezooglesince 28 Sept 2026
theoks.netOnekopakaspacesince 28 Sept 2026
serverfault.comServer Faultsince 28 Sept 2026
sussex.ac.ukUniversity of Sussex - a leading, research-intensive universitysince 28 Sept 2026
safer-networking.orgHome of Spybot, Your Digital Identity Protection - Spybot Anti-Malware and Antivirus : Spybot Anti-Malware and Antivirussince 28 Sept 2026
breuninger.comBREUNINGER | Luxus, Fashion & Beauty online shoppensince 28 Sept 2026
frankerfacez.comFrankerFaceZsince 28 Sept 2026
mozdev.orgInternet for people, not profit — Mozilla Globalsince 28 Sept 2026
mythic-beasts.comMythic Beasts - Mythic Beastssince 28 Sept 2026
pixeldrain.devCloud storage and data transfer services ~ pixeldrainsince 28 Sept 2026
getfirefox.comGet Firefox for desktop and mobile — Firefox.comsince 28 Sept 2026
sstatic.netPage not found - Stack Overflowsince 28 Sept 2026
pcgameshardware.dePCGH: Computer, PC Gaming, Kaufberatungsince 28 Sept 2026
optifine.netOptiFinesince 28 Sept 2026
marketingautomation.servicesConstant Contact Loginsince 28 Sept 2026
joinpeertube.orgWhat is PeerTube? | JoinPeerTubesince 28 Sept 2026
work.den@work der Internetprovider für Geschäftskunden in Hamburgsince 28 Sept 2026
pcgames.dePC Games: Gaming, Entertainment, Tests, Guides & Dealssince 28 Sept 2026
lineageos.orgLineageOS – LineageOS Android Distributionsince 28 Sept 2026
framasoft.orgFramasoftsince 28 Sept 2026
mathoverflow.netMathOverflowsince 28 Sept 2026
sanger.ac.ukWellcome Sanger Institute - Genomics Research Institute in Cambridgesince 28 Sept 2026
tghn.orgHome • The Global Health Networksince 28 Sept 2026
pluralistic.netPluralistic: Daily links from Cory Doctorow – No trackers, no ads. Black type, white background. Privacy policy: we don't collect or retain any data at all ever period.since 28 Sept 2026
moly.huMolysince 28 Sept 2026
tickcounter.comMake Your Countdown Timer For Free - TickCountersince 28 Sept 2026
craphound.comCory Doctorow's craphound.com | Cory Doctorow's Literary Workssince 28 Sept 2026