diff --git a/Userland/Libraries/LibWeb/URL/URL.cpp b/Userland/Libraries/LibWeb/URL/URL.cpp
index 09bb522f9e..57944b664e 100644
--- a/Userland/Libraries/LibWeb/URL/URL.cpp
+++ b/Userland/Libraries/LibWeb/URL/URL.cpp
@@ -5,6 +5,8 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
+#include <AK/IPv4Address.h>
+#include <AK/IPv6Address.h>
 #include <AK/URLParser.h>
 #include <LibWeb/Bindings/Intrinsics.h>
 #include <LibWeb/URL/URL.h>
@@ -340,4 +342,13 @@ HTML::Origin url_origin(AK::URL const& url)
     return HTML::Origin {};
 }
 
+// https://url.spec.whatwg.org/#concept-domain
+bool host_is_domain(StringView host)
+{
+    // A domain is a non-empty ASCII string that identifies a realm within a network.
+    return !host.is_empty()
+        && !IPv4Address::from_string(host).has_value()
+        && !IPv6Address::from_string(host).has_value();
+}
+
 }
diff --git a/Userland/Libraries/LibWeb/URL/URL.h b/Userland/Libraries/LibWeb/URL/URL.h
index 44d5add4fd..e2af21fa3e 100644
--- a/Userland/Libraries/LibWeb/URL/URL.h
+++ b/Userland/Libraries/LibWeb/URL/URL.h
@@ -72,5 +72,6 @@ private:
 };
 
 HTML::Origin url_origin(AK::URL const&);
+bool host_is_domain(StringView host);
 
 }