Add HTML lang attribute SEO check (#84) (#124)

aouwalitshikkha · web-flow · commit 0d38b6cbfd4e · 2026-06-19T11:53:07.000-05:00
Detects missing or empty lang attribute on <html> tag and reports it as a warning. Follows the same pattern as existing checks (h1, img alt, og tags). Closes #84
diff --git a/pyseoanalyzer/page.py b/pyseoanalyzer/page.py
@@ -273,6 +273,7 @@ def get_meta_value(key):
         self.analyze_a_tags(soup_unmodified)
         self.analyze_img_tags(soup_lower)
         self.analyze_h1_tags(soup_lower)
+        self.analyze_html_lang(soup_lower)
 
         if self.analyze_headings:
             self.analyze_heading_tags(soup_unmodified)
@@ -449,6 +450,14 @@ def analyze_h1_tags(self, bs):
         if len(htags) == 0:
             self.warn("Each page should have at least one h1 tag")
 
+    def analyze_html_lang(self, bs):
+        """
+        Make sure the HTML tag has a lang attribute
+        """
+        html_tag = bs.find("html")
+        if html_tag is not None and not html_tag.get("lang"):
+            self.warn("Missing lang attribute on <html> tag")
+
     def analyze_a_tags(self, bs):
         """
         Add any new links (that we didn't find in the sitemap)
diff --git a/tests/test_page.py b/tests/test_page.py
@@ -30,6 +30,31 @@ def test_analyze():
     assert "seth" in p.title.lower()
 
 
+def test_analyze_html_lang_missing():
+    from bs4 import BeautifulSoup
+
+    p = page.Page(url="https://example.com/", base_domain="https://example.com/")
+    soup = BeautifulSoup(
+        "<html><head><title>Test</title></head><body><p>Hello</p></body></html>",
+        "html.parser",
+    )
+    p.analyze_html_lang(soup)
+    assert len(p.warnings) == 1
+    assert "lang" in p.warnings[0].lower()
+
+
+def test_analyze_html_lang_present():
+    from bs4 import BeautifulSoup
+
+    p = page.Page(url="https://example.com/", base_domain="https://example.com/")
+    soup = BeautifulSoup(
+        '<html lang="en"><head><title>Test</title></head><body><p>Hello</p></body></html>',
+        "html.parser",
+    )
+    p.analyze_html_lang(soup)
+    assert len(p.warnings) == 0
+
+
 def test_analyze_with_llm():
     p = page.Page(
         url="https://www.sethserver.com/",
