diff --git a/AK/URL.cpp b/AK/URL.cpp
index e523de26862..e3460cb58df 100644
--- a/AK/URL.cpp
+++ b/AK/URL.cpp
@@ -210,4 +210,42 @@ URL URL::complete_url(const String& string) const
     return url;
 }
 
+void URL::set_protocol(const String& protocol)
+{
+    m_protocol = protocol;
+    m_valid = compute_validity();
+}
+
+void URL::set_host(const String& host)
+{
+    m_host = host;
+    m_valid = compute_validity();
+}
+
+void URL::set_path(const String& path)
+{
+    m_path = path;
+    m_valid = compute_validity();
+}
+
+void URL::set_query(const String& query)
+{
+    m_query = query;
+}
+
+bool URL::compute_validity() const
+{
+    // FIXME: This is by no means complete.
+    if (m_protocol.is_empty())
+        return false;
+    if (m_protocol == "http" || m_protocol == "https") {
+        if (m_host.is_empty())
+            return false;
+    } else if (m_protocol == "file") {
+        if (m_path.is_empty())
+            return false;
+    }
+    return true;
+}
+
 }
diff --git a/AK/URL.h b/AK/URL.h
index a3818160410..f057a3c9463 100644
--- a/AK/URL.h
+++ b/AK/URL.h
@@ -53,10 +53,10 @@ public:
     String query() const { return m_query; }
     u16 port() const { return m_port; }
 
-    void set_protocol(const String& protocol) { m_protocol = protocol; }
-    void set_host(const String& host) { m_host = host; }
-    void set_path(const String& path) { m_path = path; }
-    void set_query(const String& query) { m_query = query; }
+    void set_protocol(const String& protocol);
+    void set_host(const String& host);
+    void set_path(const String& path);
+    void set_query(const String& query);
     void set_port(u16 port) { m_port = port; }
 
     String to_string() const;
@@ -65,6 +65,7 @@ public:
 
 private:
     bool parse(const StringView&);
+    bool compute_validity() const;
 
     bool m_valid { false };
     u16 m_port { 80 };