diff --git a/Libraries/LibURL/URL.cpp b/Libraries/LibURL/URL.cpp
index 308cd34448..f36693ae71 100644
--- a/Libraries/LibURL/URL.cpp
+++ b/Libraries/LibURL/URL.cpp
@@ -33,16 +33,12 @@ URL::URL(StringView string)
     }
 }
 
-URL URL::complete_url(StringView relative_url) const
+Optional<URL> URL::complete_url(StringView relative_url) const
 {
     if (!is_valid())
         return {};
 
-    auto result = Parser::basic_parse(relative_url, *this);
-    if (!result.has_value())
-        return {};
-
-    return result.release_value();
+    return Parser::basic_parse(relative_url, *this);
 }
 
 ByteString URL::path_segment_at_index(size_t index) const
diff --git a/Libraries/LibURL/URL.h b/Libraries/LibURL/URL.h
index c699162a4f..86782ebd99 100644
--- a/Libraries/LibURL/URL.h
+++ b/Libraries/LibURL/URL.h
@@ -135,7 +135,7 @@ public:
 
     bool equals(URL const& other, ExcludeFragment = ExcludeFragment::No) const;
 
-    URL complete_url(StringView) const;
+    Optional<URL> complete_url(StringView) const;
 
     [[nodiscard]] bool operator==(URL const& other) const
     {
diff --git a/Libraries/LibWeb/CSS/CSSStyleSheet.cpp b/Libraries/LibWeb/CSS/CSSStyleSheet.cpp
index a91b9b6675..25fdb128ce 100644
--- a/Libraries/LibWeb/CSS/CSSStyleSheet.cpp
+++ b/Libraries/LibWeb/CSS/CSSStyleSheet.cpp
@@ -45,8 +45,8 @@ WebIDL::ExceptionOr<GC::Ref<CSSStyleSheet>> CSSStyleSheet::construct_impl(JS::Re
             sheet_location_url = sheet->location().release_value();
 
         // AD-HOC: This isn't explicitly mentioned in the specification, but multiple modern browsers do this.
-        URL::URL url = sheet->location().has_value() ? sheet_location_url->complete_url(options->base_url.value()) : options->base_url.value();
-        if (!url.is_valid())
+        Optional<URL::URL> url = sheet->location().has_value() ? sheet_location_url->complete_url(options->base_url.value()) : options->base_url.value();
+        if (!url.has_value())
             return WebIDL::NotAllowedError::create(realm, "Constructed style sheets must have a valid base URL"_string);
 
         sheet->set_base_url(url);
diff --git a/Libraries/LibWeb/CSS/Parser/Parser.cpp b/Libraries/LibWeb/CSS/Parser/Parser.cpp
index accd1ffbd2..c606f8aefb 100644
--- a/Libraries/LibWeb/CSS/Parser/Parser.cpp
+++ b/Libraries/LibWeb/CSS/Parser/Parser.cpp
@@ -1761,7 +1761,7 @@ bool Parser::is_parsing_svg_presentation_attribute() const
 
 // https://www.w3.org/TR/css-values-4/#relative-urls
 // FIXME: URLs shouldn't be completed during parsing, but when used.
-URL::URL Parser::complete_url(StringView relative_url) const
+Optional<URL::URL> Parser::complete_url(StringView relative_url) const
 {
     return m_url.complete_url(relative_url);
 }
diff --git a/Libraries/LibWeb/CSS/Parser/Parser.h b/Libraries/LibWeb/CSS/Parser/Parser.h
index 1863ecb682..b06e67fc7e 100644
--- a/Libraries/LibWeb/CSS/Parser/Parser.h
+++ b/Libraries/LibWeb/CSS/Parser/Parser.h
@@ -460,7 +460,7 @@ private:
     JS::Realm& realm() const;
     bool in_quirks_mode() const;
     bool is_parsing_svg_presentation_attribute() const;
-    URL::URL complete_url(StringView) const;
+    Optional<URL::URL> complete_url(StringView) const;
 
     GC::Ptr<DOM::Document const> m_document;
     GC::Ptr<JS::Realm> m_realm;
diff --git a/Libraries/LibWeb/CSS/Parser/ValueParsing.cpp b/Libraries/LibWeb/CSS/Parser/ValueParsing.cpp
index 2e24636aa3..bc4819bc42 100644
--- a/Libraries/LibWeb/CSS/Parser/ValueParsing.cpp
+++ b/Libraries/LibWeb/CSS/Parser/ValueParsing.cpp
@@ -2470,7 +2470,7 @@ Optional<URL::URL> Parser::parse_url_function(TokenStream<ComponentValue>& token
 
     auto convert_string_to_url = [&](StringView url_string) -> Optional<URL::URL> {
         auto url = complete_url(url_string);
-        if (url.is_valid()) {
+        if (url.has_value()) {
             transaction.commit();
             return url;
         }
diff --git a/Libraries/LibWeb/HTML/FormAssociatedElement.cpp b/Libraries/LibWeb/HTML/FormAssociatedElement.cpp
index 37e34eb07b..effb79e848 100644
--- a/Libraries/LibWeb/HTML/FormAssociatedElement.cpp
+++ b/Libraries/LibWeb/HTML/FormAssociatedElement.cpp
@@ -194,7 +194,9 @@ String FormAssociatedElement::form_action() const
     }
 
     auto document_base_url = html_element.document().base_url();
-    return document_base_url.complete_url(form_action_attribute.value()).to_string();
+    if (auto maybe_url = document_base_url.complete_url(form_action_attribute.value()); maybe_url.has_value())
+        return maybe_url->to_string();
+    return {};
 }
 
 WebIDL::ExceptionOr<void> FormAssociatedElement::set_form_action(String const& value)
diff --git a/Libraries/LibWeb/HTML/HTMLBaseElement.cpp b/Libraries/LibWeb/HTML/HTMLBaseElement.cpp
index d484629f4c..a745680565 100644
--- a/Libraries/LibWeb/HTML/HTMLBaseElement.cpp
+++ b/Libraries/LibWeb/HTML/HTMLBaseElement.cpp
@@ -74,12 +74,12 @@ void HTMLBaseElement::set_the_frozen_base_url()
 
     // 3. Set element's frozen base URL to document's fallback base URL, if urlRecord is failure or running Is base allowed for Document? on the resulting URL record and document returns "Blocked", and to urlRecord otherwise.
     // FIXME: Apply "Is base allowed for Document?" CSP
-    if (!url_record.is_valid()) {
+    if (!url_record.has_value()) {
         m_frozen_base_url = document.fallback_base_url();
         return;
     }
 
-    m_frozen_base_url = move(url_record);
+    m_frozen_base_url = url_record.release_value();
 }
 
 // https://html.spec.whatwg.org/multipage/semantics.html#dom-base-href
@@ -96,11 +96,11 @@ String HTMLBaseElement::href() const
     auto url_record = document.fallback_base_url().complete_url(url);
 
     // 4. If urlRecord is failure, return url.
-    if (!url_record.is_valid())
+    if (!url_record.has_value())
         return url;
 
     // 5. Return the serialization of urlRecord.
-    return url_record.to_string();
+    return url_record->to_string();
 }
 
 // https://html.spec.whatwg.org/multipage/semantics.html#dom-base-href
diff --git a/Libraries/LibWeb/HTML/HTMLFormElement.cpp b/Libraries/LibWeb/HTML/HTMLFormElement.cpp
index 8b6db2f250..7d17382c89 100644
--- a/Libraries/LibWeb/HTML/HTMLFormElement.cpp
+++ b/Libraries/LibWeb/HTML/HTMLFormElement.cpp
@@ -619,7 +619,9 @@ String HTMLFormElement::action() const
         return document().url_string();
     }
 
-    return document().base_url().complete_url(form_action_attribute.value()).to_string();
+    if (auto maybe_url = document().base_url().complete_url(form_action_attribute.value()); maybe_url.has_value())
+        return maybe_url->to_string();
+    return {};
 }
 
 // https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#dom-fs-action
diff --git a/Libraries/LibWeb/SVG/SVGTextPathElement.cpp b/Libraries/LibWeb/SVG/SVGTextPathElement.cpp
index 044cab2b02..f583c56812 100644
--- a/Libraries/LibWeb/SVG/SVGTextPathElement.cpp
+++ b/Libraries/LibWeb/SVG/SVGTextPathElement.cpp
@@ -25,7 +25,9 @@ GC::Ptr<SVGGeometryElement const> SVGTextPathElement::path_or_shape() const
     if (!href.has_value())
         return {};
     auto url = document().url().complete_url(*href);
-    return try_resolve_url_to<SVGGeometryElement const>(url);
+    if (!url.has_value())
+        return {};
+    return try_resolve_url_to<SVGGeometryElement const>(*url);
 }
 
 void SVGTextPathElement::initialize(JS::Realm& realm)
diff --git a/Libraries/LibWeb/SVG/SVGUseElement.cpp b/Libraries/LibWeb/SVG/SVGUseElement.cpp
index 2cb4344529..ac8f274410 100644
--- a/Libraries/LibWeb/SVG/SVGUseElement.cpp
+++ b/Libraries/LibWeb/SVG/SVGUseElement.cpp
@@ -79,19 +79,19 @@ void SVGUseElement::process_the_url(Optional<String> const& href)
     // a same-document URL reference, and processing the URL must continue as indicated in Identifying
     // the target element with the current document as the referenced document.
     m_href = document().url().complete_url(href.value_or(String {}));
-    if (!m_href.is_valid())
+    if (!m_href.has_value())
         return;
 
     if (is_referrenced_element_same_document()) {
         clone_element_tree_as_our_shadow_tree(referenced_element());
     } else {
-        fetch_the_document(m_href);
+        fetch_the_document(*m_href);
     }
 }
 
 bool SVGUseElement::is_referrenced_element_same_document() const
 {
-    return m_href.equals(document().url(), URL::ExcludeFragment::Yes);
+    return m_href->equals(document().url(), URL::ExcludeFragment::Yes);
 }
 
 Gfx::AffineTransform SVGUseElement::element_transform() const
@@ -121,11 +121,11 @@ void SVGUseElement::svg_element_changed(SVGElement& svg_element)
 
 void SVGUseElement::svg_element_removed(SVGElement& svg_element)
 {
-    if (!m_href.fragment().has_value() || !is_referrenced_element_same_document()) {
+    if (!m_href.has_value() || !m_href->fragment().has_value() || !is_referrenced_element_same_document()) {
         return;
     }
 
-    if (AK::StringUtils::matches(svg_element.get_attribute_value("id"_fly_string), m_href.fragment().value())) {
+    if (AK::StringUtils::matches(svg_element.get_attribute_value("id"_fly_string), m_href->fragment().value())) {
         shadow_root()->remove_all_children();
     }
 }
@@ -133,14 +133,17 @@ void SVGUseElement::svg_element_removed(SVGElement& svg_element)
 // https://svgwg.org/svg2-draft/linking.html#processingURL-target
 GC::Ptr<DOM::Element> SVGUseElement::referenced_element()
 {
-    if (!m_href.is_valid())
+    if (!m_href.has_value())
         return nullptr;
 
-    if (!m_href.fragment().has_value())
+    if (!m_href->is_valid())
+        return nullptr;
+
+    if (!m_href->fragment().has_value())
         return nullptr;
 
     if (is_referrenced_element_same_document())
-        return document().get_element_by_id(*m_href.fragment());
+        return document().get_element_by_id(*m_href->fragment());
 
     if (!m_resource_request)
         return nullptr;
@@ -149,7 +152,7 @@ GC::Ptr<DOM::Element> SVGUseElement::referenced_element()
     if (!data || !is<SVG::SVGDecodedImageData>(*data))
         return nullptr;
 
-    return as<SVG::SVGDecodedImageData>(*data).svg_document().get_element_by_id(*m_href.fragment());
+    return as<SVG::SVGDecodedImageData>(*data).svg_document().get_element_by_id(*m_href->fragment());
 }
 
 // https://svgwg.org/svg2-draft/linking.html#processingURL-fetch
diff --git a/Libraries/LibWeb/SVG/SVGUseElement.h b/Libraries/LibWeb/SVG/SVGUseElement.h
index 5e839c05fa..7a1dea3385 100644
--- a/Libraries/LibWeb/SVG/SVGUseElement.h
+++ b/Libraries/LibWeb/SVG/SVGUseElement.h
@@ -65,7 +65,7 @@ private:
     Optional<float> m_x;
     Optional<float> m_y;
 
-    URL::URL m_href;
+    Optional<URL::URL> m_href;
 
     GC::Ptr<DOM::DocumentObserver> m_document_observer;
     GC::Ptr<HTML::SharedResourceRequest> m_resource_request;
diff --git a/Tests/LibURL/TestURL.cpp b/Tests/LibURL/TestURL.cpp
index 18858d53a4..ba4f13b760 100644
--- a/Tests/LibURL/TestURL.cpp
+++ b/Tests/LibURL/TestURL.cpp
@@ -195,10 +195,10 @@ TEST_CASE(file_url_serialization)
 
 TEST_CASE(file_url_relative)
 {
-    EXPECT_EQ(URL::URL("https://vkoskiv.com/index.html"sv).complete_url("/static/foo.js"sv).serialize(), "https://vkoskiv.com/static/foo.js");
-    EXPECT_EQ(URL::URL("file:///home/vkoskiv/test/index.html"sv).complete_url("/static/foo.js"sv).serialize(), "file:///static/foo.js");
-    EXPECT_EQ(URL::URL("https://vkoskiv.com/index.html"sv).complete_url("static/foo.js"sv).serialize(), "https://vkoskiv.com/static/foo.js");
-    EXPECT_EQ(URL::URL("file:///home/vkoskiv/test/index.html"sv).complete_url("static/foo.js"sv).serialize(), "file:///home/vkoskiv/test/static/foo.js");
+    EXPECT_EQ(URL::URL("https://vkoskiv.com/index.html"sv).complete_url("/static/foo.js"sv)->serialize(), "https://vkoskiv.com/static/foo.js");
+    EXPECT_EQ(URL::URL("file:///home/vkoskiv/test/index.html"sv).complete_url("/static/foo.js"sv)->serialize(), "file:///static/foo.js");
+    EXPECT_EQ(URL::URL("https://vkoskiv.com/index.html"sv).complete_url("static/foo.js"sv)->serialize(), "https://vkoskiv.com/static/foo.js");
+    EXPECT_EQ(URL::URL("file:///home/vkoskiv/test/index.html"sv).complete_url("static/foo.js"sv)->serialize(), "file:///home/vkoskiv/test/static/foo.js");
 }
 
 TEST_CASE(about_url)
@@ -243,10 +243,10 @@ TEST_CASE(mailto_url_with_subject)
 
 TEST_CASE(trailing_slash_with_complete_url)
 {
-    EXPECT_EQ(URL::URL("http://a/b/"sv).complete_url("c/"sv).serialize(), "http://a/b/c/");
-    EXPECT_EQ(URL::URL("http://a/b/"sv).complete_url("c"sv).serialize(), "http://a/b/c");
-    EXPECT_EQ(URL::URL("http://a/b"sv).complete_url("c/"sv).serialize(), "http://a/c/");
-    EXPECT_EQ(URL::URL("http://a/b"sv).complete_url("c"sv).serialize(), "http://a/c");
+    EXPECT_EQ(URL::URL("http://a/b/"sv).complete_url("c/"sv)->serialize(), "http://a/b/c/");
+    EXPECT_EQ(URL::URL("http://a/b/"sv).complete_url("c"sv)->serialize(), "http://a/b/c");
+    EXPECT_EQ(URL::URL("http://a/b"sv).complete_url("c/"sv)->serialize(), "http://a/c/");
+    EXPECT_EQ(URL::URL("http://a/b"sv).complete_url("c"sv)->serialize(), "http://a/c");
 }
 
 TEST_CASE(trailing_port)
@@ -297,15 +297,15 @@ TEST_CASE(create_with_file_scheme)
 TEST_CASE(complete_url)
 {
     URL::URL base_url("http://serenityos.org/index.html#fragment"sv);
-    URL::URL url = base_url.complete_url("test.html"sv);
-    EXPECT(url.is_valid());
-    EXPECT_EQ(url.scheme(), "http");
-    EXPECT_EQ(url.serialized_host(), "serenityos.org");
-    EXPECT_EQ(url.serialize_path(), "/test.html");
-    EXPECT(!url.query().has_value());
-    EXPECT_EQ(url.cannot_be_a_base_url(), false);
+    auto url = base_url.complete_url("test.html"sv);
+    EXPECT(url.has_value());
+    EXPECT_EQ(url->scheme(), "http");
+    EXPECT_EQ(url->serialized_host(), "serenityos.org");
+    EXPECT_EQ(url->serialize_path(), "/test.html");
+    EXPECT(!url->query().has_value());
+    EXPECT_EQ(url->cannot_be_a_base_url(), false);
 
-    EXPECT(base_url.complete_url("../index.html#fragment"sv).equals(base_url));
+    EXPECT(base_url.complete_url("../index.html#fragment"sv)->equals(base_url));
 }
 
 TEST_CASE(leading_whitespace)
@@ -385,8 +385,8 @@ TEST_CASE(complete_file_url_with_base)
     EXPECT_EQ(url.path_segment_at_index(1), "index.html");
 
     auto sub_url = url.complete_url("js/app.js"sv);
-    EXPECT(sub_url.is_valid());
-    EXPECT_EQ(sub_url.serialize_path(), "/home/js/app.js");
+    EXPECT(sub_url.has_value());
+    EXPECT_EQ(sub_url->serialize_path(), "/home/js/app.js");
 }
 
 TEST_CASE(empty_url_with_base_url)
diff --git a/Tests/LibWeb/TestFetchURL.cpp b/Tests/LibWeb/TestFetchURL.cpp
index 031ab0ed1a..265fb88936 100644
--- a/Tests/LibWeb/TestFetchURL.cpp
+++ b/Tests/LibWeb/TestFetchURL.cpp
@@ -102,12 +102,12 @@ TEST_CASE(data_url_base64_encoded_with_inline_whitespace)
 TEST_CASE(data_url_completed_with_fragment)
 {
     auto url = URL::URL("data:text/plain,test"sv).complete_url("#a"sv);
-    EXPECT(url.is_valid());
-    EXPECT_EQ(url.scheme(), "data");
-    EXPECT_EQ(url.fragment(), "a");
-    EXPECT(!url.host().has_value());
+    EXPECT(url.has_value());
+    EXPECT_EQ(url->scheme(), "data");
+    EXPECT_EQ(url->fragment(), "a");
+    EXPECT(!url->host().has_value());
 
-    auto data_url = TRY_OR_FAIL(Web::Fetch::Infrastructure::process_data_url(url));
+    auto data_url = TRY_OR_FAIL(Web::Fetch::Infrastructure::process_data_url(*url));
     EXPECT_EQ(data_url.mime_type.serialized(), "text/plain");
     EXPECT_EQ(StringView(data_url.body.bytes()), "test"sv);
 }