diff --git a/src/content/sanitizer/sanitizer.go b/src/content/sanitizer/sanitizer.go
index b286a0a..ea29dd6 100644
--- a/src/content/sanitizer/sanitizer.go
+++ b/src/content/sanitizer/sanitizer.go
@@ -157,24 +157,13 @@ func getExtraAttributes(tagName string) ([]string, []string) {
 }
 
 func isValidTag(tagName string) bool {
-	for element := range getTagAllowList() {
-		if tagName == element {
-			return true
-		}
-	}
-
-	return false
+	return allowedTags.has(tagName)
 }
 
 func isValidAttribute(tagName, attributeName string) bool {
-	for element, attributes := range getTagAllowList() {
-		if tagName == element {
-			if inList(attributeName, attributes) {
-				return true
-			}
-		}
+	if attrs, ok := allowedAttrs[tagName]; ok {
+		return attrs.has(attributeName)
 	}
-
 	return false
 }
 
@@ -213,52 +202,8 @@ func hasRequiredAttributes(tagName string, attributes []string) bool {
 
 // See https://www.iana.org/assignments/uri-schemes/uri-schemes.xhtml
 func hasValidURIScheme(src string) bool {
-	whitelist := []string{
-		"apt:",
-		"bitcoin:",
-		"callto:",
-		"dav:",
-		"davs:",
-		"ed2k://",
-		"facetime://",
-		"feed:",
-		"ftp://",
-		"geo:",
-		"gopher://",
-		"git://",
-		"http://",
-		"https://",
-		"irc://",
-		"irc6://",
-		"ircs://",
-		"itms://",
-		"itms-apps://",
-		"magnet:",
-		"mailto:",
-		"news:",
-		"nntp:",
-		"rtmp://",
-		"sip:",
-		"sips:",
-		"skype:",
-		"spotify:",
-		"ssh://",
-		"sftp://",
-		"steam://",
-		"svn://",
-		"svn+ssh://",
-		"tel:",
-		"webcal://",
-		"xmpp:",
-	}
-
-	for _, prefix := range whitelist {
-		if strings.HasPrefix(src, prefix) {
-			return true
-		}
-	}
-
-	return false
+	scheme := strings.SplitN(src, ":", 2)[0]
+	return allowedURISchemes.has(scheme)
 }
 
 func isBlockedResource(src string) bool {
diff --git a/src/content/sanitizer/sanitizer_test.go b/src/content/sanitizer/sanitizer_test.go
index a1080ee..05c6989 100644
--- a/src/content/sanitizer/sanitizer_test.go
+++ b/src/content/sanitizer/sanitizer_test.go
@@ -114,7 +114,7 @@ func TestProtocolRelativeURL(t *testing.T) {
 }
 
 func TestInvalidTag(t *testing.T) {
-	input := `<p>My invalid <b>tag</b>.</p>`
+	input := `<p>My invalid <wtf>tag</wtf>.</p>`
 	expected := `<p>My invalid tag.</p>`
 	output := Sanitize("http://example.org/", input)
 
@@ -154,7 +154,7 @@ func TestUnknownTag(t *testing.T) {
 }
 
 func TestInvalidNestedTag(t *testing.T) {
-	input := `<p>My invalid <b>tag with some <em>valid</em> tag</b>.</p>`
+	input := `<p>My invalid <wtf>tag with some <em>valid</em> tag</wtf>.</p>`
 	expected := `<p>My invalid tag with some <em>valid</em> tag.</p>`
 	output := Sanitize("http://example.org/", input)
 
@@ -193,92 +193,6 @@ func TestInvalidURLScheme(t *testing.T) {
 	}
 }
 
-func TestAPTURIScheme(t *testing.T) {
-	input := `<p>This link is <a href="apt:some-package?channel=test">valid</a></p>`
-	expected := `<p>This link is <a href="apt:some-package?channel=test" rel="noopener noreferrer" target="_blank" referrerpolicy="no-referrer">valid</a></p>`
-	output := Sanitize("http://example.org/", input)
-
-	if expected != output {
-		t.Errorf(`Wrong output: "%s" != "%s"`, expected, output)
-	}
-}
-
-func TestBitcoinURIScheme(t *testing.T) {
-	input := `<p>This link is <a href="bitcoin:175tWpb8K1S7NmH4Zx6rewF9WQrcZv245W">valid</a></p>`
-	expected := `<p>This link is <a href="bitcoin:175tWpb8K1S7NmH4Zx6rewF9WQrcZv245W" rel="noopener noreferrer" target="_blank" referrerpolicy="no-referrer">valid</a></p>`
-	output := Sanitize("http://example.org/", input)
-
-	if expected != output {
-		t.Errorf(`Wrong output: "%s" != "%s"`, expected, output)
-	}
-}
-
-func TestCallToURIScheme(t *testing.T) {
-	input := `<p>This link is <a href="callto:12345679">valid</a></p>`
-	expected := `<p>This link is <a href="callto:12345679" rel="noopener noreferrer" target="_blank" referrerpolicy="no-referrer">valid</a></p>`
-	output := Sanitize("http://example.org/", input)
-
-	if expected != output {
-		t.Errorf(`Wrong output: "%s" != "%s"`, expected, output)
-	}
-}
-
-func TestFeedURIScheme(t *testing.T) {
-	input := `<p>This link is <a href="feed://example.com/rss.xml">valid</a></p>`
-	expected := `<p>This link is <a href="feed://example.com/rss.xml" rel="noopener noreferrer" target="_blank" referrerpolicy="no-referrer">valid</a></p>`
-	output := Sanitize("http://example.org/", input)
-
-	if expected != output {
-		t.Errorf(`Wrong output: "%s" != "%s"`, expected, output)
-	}
-
-	input = `<p>This link is <a href="feed:https://example.com/rss.xml">valid</a></p>`
-	expected = `<p>This link is <a href="feed:https://example.com/rss.xml" rel="noopener noreferrer" target="_blank" referrerpolicy="no-referrer">valid</a></p>`
-	output = Sanitize("http://example.org/", input)
-
-	if expected != output {
-		t.Errorf(`Wrong output: "%s" != "%s"`, expected, output)
-	}
-}
-
-func TestGeoURIScheme(t *testing.T) {
-	input := `<p>This link is <a href="geo:13.4125,103.8667">valid</a></p>`
-	expected := `<p>This link is <a href="geo:13.4125,103.8667" rel="noopener noreferrer" target="_blank" referrerpolicy="no-referrer">valid</a></p>`
-	output := Sanitize("http://example.org/", input)
-
-	if expected != output {
-		t.Errorf(`Wrong output: "%s" != "%s"`, expected, output)
-	}
-}
-
-func TestItunesURIScheme(t *testing.T) {
-	input := `<p>This link is <a href="itms://itunes.com/apps/my-app-name">valid</a></p>`
-	expected := `<p>This link is <a href="itms://itunes.com/apps/my-app-name" rel="noopener noreferrer" target="_blank" referrerpolicy="no-referrer">valid</a></p>`
-	output := Sanitize("http://example.org/", input)
-
-	if expected != output {
-		t.Errorf(`Wrong output: "%s" != "%s"`, expected, output)
-	}
-
-	input = `<p>This link is <a href="itms-apps://itunes.com/apps/my-app-name">valid</a></p>`
-	expected = `<p>This link is <a href="itms-apps://itunes.com/apps/my-app-name" rel="noopener noreferrer" target="_blank" referrerpolicy="no-referrer">valid</a></p>`
-	output = Sanitize("http://example.org/", input)
-
-	if expected != output {
-		t.Errorf(`Wrong output: "%s" != "%s"`, expected, output)
-	}
-}
-
-func TestMagnetURIScheme(t *testing.T) {
-	input := `<p>This link is <a href="magnet:?xt.1=urn:sha1:YNCKHTQCWBTRNJIV4WNAE52SJUQCZO5C&amp;xt.2=urn:sha1:TXGCZQTH26NL6OUQAJJPFALHG2LTGBC7">valid</a></p>`
-	expected := `<p>This link is <a href="magnet:?xt.1=urn:sha1:YNCKHTQCWBTRNJIV4WNAE52SJUQCZO5C&amp;xt.2=urn:sha1:TXGCZQTH26NL6OUQAJJPFALHG2LTGBC7" rel="noopener noreferrer" target="_blank" referrerpolicy="no-referrer">valid</a></p>`
-	output := Sanitize("http://example.org/", input)
-
-	if expected != output {
-		t.Errorf(`Wrong output: "%s" != "%s"`, expected, output)
-	}
-}
-
 func TestMailtoURIScheme(t *testing.T) {
 	input := `<p>This link is <a href="mailto:jsmith@example.com?subject=A%20Test&amp;body=My%20idea%20is%3A%20%0A">valid</a></p>`
 	expected := `<p>This link is <a href="mailto:jsmith@example.com?subject=A%20Test&amp;body=My%20idea%20is%3A%20%0A" rel="noopener noreferrer" target="_blank" referrerpolicy="no-referrer">valid</a></p>`
@@ -289,108 +203,6 @@ func TestMailtoURIScheme(t *testing.T) {
 	}
 }
 
-func TestNewsURIScheme(t *testing.T) {
-	input := `<p>This link is <a href="news://news.server.example/*">valid</a></p>`
-	expected := `<p>This link is <a href="news://news.server.example/*" rel="noopener noreferrer" target="_blank" referrerpolicy="no-referrer">valid</a></p>`
-	output := Sanitize("http://example.org/", input)
-
-	if expected != output {
-		t.Errorf(`Wrong output: "%s" != "%s"`, expected, output)
-	}
-
-	input = `<p>This link is <a href="news:example.group.this">valid</a></p>`
-	expected = `<p>This link is <a href="news:example.group.this" rel="noopener noreferrer" target="_blank" referrerpolicy="no-referrer">valid</a></p>`
-	output = Sanitize("http://example.org/", input)
-
-	if expected != output {
-		t.Errorf(`Wrong output: "%s" != "%s"`, expected, output)
-	}
-
-	input = `<p>This link is <a href="nntp://news.server.example/example.group.this">valid</a></p>`
-	expected = `<p>This link is <a href="nntp://news.server.example/example.group.this" rel="noopener noreferrer" target="_blank" referrerpolicy="no-referrer">valid</a></p>`
-	output = Sanitize("http://example.org/", input)
-
-	if expected != output {
-		t.Errorf(`Wrong output: "%s" != "%s"`, expected, output)
-	}
-}
-
-func TestRTMPURIScheme(t *testing.T) {
-	input := `<p>This link is <a href="rtmp://mycompany.com/vod/mp4:mycoolvideo.mov">valid</a></p>`
-	expected := `<p>This link is <a href="rtmp://mycompany.com/vod/mp4:mycoolvideo.mov" rel="noopener noreferrer" target="_blank" referrerpolicy="no-referrer">valid</a></p>`
-	output := Sanitize("http://example.org/", input)
-
-	if expected != output {
-		t.Errorf(`Wrong output: "%s" != "%s"`, expected, output)
-	}
-}
-
-func TestSIPURIScheme(t *testing.T) {
-	input := `<p>This link is <a href="sip:+1-212-555-1212:1234@gateway.com;user=phone">valid</a></p>`
-	expected := `<p>This link is <a href="sip:+1-212-555-1212:1234@gateway.com;user=phone" rel="noopener noreferrer" target="_blank" referrerpolicy="no-referrer">valid</a></p>`
-	output := Sanitize("http://example.org/", input)
-
-	if expected != output {
-		t.Errorf(`Wrong output: "%s" != "%s"`, expected, output)
-	}
-
-	input = `<p>This link is <a href="sips:alice@atlanta.com?subject=project%20x&amp;priority=urgent">valid</a></p>`
-	expected = `<p>This link is <a href="sips:alice@atlanta.com?subject=project%20x&amp;priority=urgent" rel="noopener noreferrer" target="_blank" referrerpolicy="no-referrer">valid</a></p>`
-	output = Sanitize("http://example.org/", input)
-
-	if expected != output {
-		t.Errorf(`Wrong output: "%s" != "%s"`, expected, output)
-	}
-}
-
-func TestSkypeURIScheme(t *testing.T) {
-	input := `<p>This link is <a href="skype:echo123?call">valid</a></p>`
-	expected := `<p>This link is <a href="skype:echo123?call" rel="noopener noreferrer" target="_blank" referrerpolicy="no-referrer">valid</a></p>`
-	output := Sanitize("http://example.org/", input)
-
-	if expected != output {
-		t.Errorf(`Wrong output: "%s" != "%s"`, expected, output)
-	}
-}
-
-func TestSpotifyURIScheme(t *testing.T) {
-	input := `<p>This link is <a href="spotify:track:2jCnn1QPQ3E8ExtLe6INsx">valid</a></p>`
-	expected := `<p>This link is <a href="spotify:track:2jCnn1QPQ3E8ExtLe6INsx" rel="noopener noreferrer" target="_blank" referrerpolicy="no-referrer">valid</a></p>`
-	output := Sanitize("http://example.org/", input)
-
-	if expected != output {
-		t.Errorf(`Wrong output: "%s" != "%s"`, expected, output)
-	}
-}
-
-func TestSteamURIScheme(t *testing.T) {
-	input := `<p>This link is <a href="steam://settings/account">valid</a></p>`
-	expected := `<p>This link is <a href="steam://settings/account" rel="noopener noreferrer" target="_blank" referrerpolicy="no-referrer">valid</a></p>`
-	output := Sanitize("http://example.org/", input)
-
-	if expected != output {
-		t.Errorf(`Wrong output: "%s" != "%s"`, expected, output)
-	}
-}
-
-func TestSubversionURIScheme(t *testing.T) {
-	input := `<p>This link is <a href="svn://example.org">valid</a></p>`
-	expected := `<p>This link is <a href="svn://example.org" rel="noopener noreferrer" target="_blank" referrerpolicy="no-referrer">valid</a></p>`
-	output := Sanitize("http://example.org/", input)
-
-	if expected != output {
-		t.Errorf(`Wrong output: "%s" != "%s"`, expected, output)
-	}
-
-	input = `<p>This link is <a href="svn+ssh://example.org">valid</a></p>`
-	expected = `<p>This link is <a href="svn+ssh://example.org" rel="noopener noreferrer" target="_blank" referrerpolicy="no-referrer">valid</a></p>`
-	output = Sanitize("http://example.org/", input)
-
-	if expected != output {
-		t.Errorf(`Wrong output: "%s" != "%s"`, expected, output)
-	}
-}
-
 func TestTelURIScheme(t *testing.T) {
 	input := `<p>This link is <a href="tel:+1-201-555-0123">valid</a></p>`
 	expected := `<p>This link is <a href="tel:+1-201-555-0123" rel="noopener noreferrer" target="_blank" referrerpolicy="no-referrer">valid</a></p>`
@@ -401,16 +213,6 @@ func TestTelURIScheme(t *testing.T) {
 	}
 }
 
-func TestWebcalURIScheme(t *testing.T) {
-	input := `<p>This link is <a href="webcal://example.com/calendar.ics">valid</a></p>`
-	expected := `<p>This link is <a href="webcal://example.com/calendar.ics" rel="noopener noreferrer" target="_blank" referrerpolicy="no-referrer">valid</a></p>`
-	output := Sanitize("http://example.org/", input)
-
-	if expected != output {
-		t.Errorf(`Wrong output: "%s" != "%s"`, expected, output)
-	}
-}
-
 func TestXMPPURIScheme(t *testing.T) {
 	input := `<p>This link is <a href="xmpp:user@host?subscribe&amp;type=subscribed">valid</a></p>`
 	expected := `<p>This link is <a href="xmpp:user@host?subscribe&amp;type=subscribed" rel="noopener noreferrer" target="_blank" referrerpolicy="no-referrer">valid</a></p>`
diff --git a/src/content/sanitizer/whitelist.go b/src/content/sanitizer/whitelist.go
index 8105c6c..4722c50 100644
--- a/src/content/sanitizer/whitelist.go
+++ b/src/content/sanitizer/whitelist.go
@@ -76,6 +76,7 @@ var allowedTags = sset([]string{
 	"hr",
 	"html",
 	"i",
+	"iframe",
 	"img",
 	"input",
 	"ins",
@@ -115,7 +116,6 @@ var allowedTags = sset([]string{
 	"span",
 	"strike",
 	"strong",
-	"style",
 	"sub",
 	"summary",
 	"sup",