What does that referrer mean?
Analytics reports are full of referrers that don't look like websites, or that stop at the domain. These pages explain 36 of the common ones and why they look the way they do.
Search engines
android-app://com.google.android.googlequicksearchbox
Google app on Android
android-app://com.google.android.googlequicksearchbox/https/www.google.com
Google app on Android (with google.com path)
www.google.com
Google Search (no keyword)
www.bing.com
Bing
duckduckgo.com
DuckDuckGo
search.brave.com
Brave Search
www.startpage.com
Startpage
kagi.com
Kagi
AI assistants
chatgpt.com
ChatGPT
gemini.google.com
Google Gemini
copilot.microsoft.com
Microsoft Copilot
perplexity.ai
Perplexity
claude.ai
Claude
Social networks and link shorteners
android-app://com.linkedin.android
LinkedIn app on Android
android-app://com.reddit.frontpage
Reddit app on Android
android-app://com.twitter.android
X (formerly Twitter) app on Android
android-app://com.google.android.youtube
YouTube app on Android
l.facebook.com
Facebook link redirect (link shim)
lm.facebook.com
Facebook link redirect (mobile)
l.instagram.com
Instagram link redirect
t.co
X (Twitter) link shortener
lnkd.in
LinkedIn short link
www.linkedin.com
LinkedIn website
www.youtube.com
YouTube (via youtube.com/redirect)
news.ycombinator.com
Hacker News
Chat and work apps
android-app://com.Slack
Slack app on Android
android-app://org.telegram.messenger
Telegram app on Android
android-app://com.microsoft.teams
Microsoft Teams app on Android
android-app://com.whatsapp
WhatsApp app on Android
statics.teams.cdn.office.net
Microsoft Teams link check
app.slack.com
Slack in a web browser
android-app://com.google.android.gm
Gmail app on Android
mail.google.com
Gmail on the web
safelinks.protection.outlook.com
Microsoft Safe Links (Outlook)
News apps
android-app://com.google.android.apps.magazines
Google News app on Android
news.google.com
Google News (web)
Why referrers lose their detail
Browsers decide how much of the previous page's address to send. The default policy in current browsers is strict-origin-when-cross-origin: when a visitor follows a link from one site to another, only the origin (the scheme, domain and port) is sent, without the path or query. That's why most referrers stop at the domain. A link from an HTTPS page to an HTTP page sends no referrer at all, and a link marked rel="noreferrer" sends none either.
For cross-origin requests send the origin (only) when the protocol security level stays same (HTTPS→HTTPS).
Referrer-Policy header - MDN
With this policy, only the origin is sent in the Referer header of cross-origin requests.
A new default Referrer-Policy for Chrome: strict-origin-when-cross-origin
Don't send the Referer header to less secure destinations (HTTPS→HTTP).
Referrer-Policy header - MDN
instructs the browser, when navigating to the target resource, to omit the Referer header
rel="noreferrer" - MDN
Why some referrers start with android-app://
When an Android app opens a link in the browser, it can name itself as the referrer with an android-app:// address built from its package name. There's no web page behind it, so that package name is all you get.
it can also use the android-app: scheme to identify a native application that it came from.
Intent.EXTRA_REFERRER - Android Developers
otherwise, if known, an android-app: referrer URI containing the package name that started the Intent will be returned.
Activity.getReferrer() - Android Developers
You can set your app as the referrer when launching your Custom Tab. This way you can let websites know where their traffic is coming from.
Customizing the UI - Chrome Custom Tabs
Link shims and redirects
Some services send every outgoing click through their own address first, such as l.facebook.com or t.co. The browser then reports that address as the referrer, not the post the link was in.
Every page here is backed by the sources it links to, checked on 2026-10-06.