Years after posting the video titled “Will removing ‘.html’ from my URLs help my site?”, Google’s John Mueller still stands by his answer: URL extensions do not matter for SEO. Whether your URL ends in .htm, .html, or has no extension at all, it makes no difference to Google’s search rankings.
This topic recently came up again in a Reddit thread, where a user asked:
“”Does It Help or Hurt? If Specific Content Pages End in .htm / .html””
John Mueller replied:
“”Doesn’t matter. Also, no extension is fine. (The whole thing is historical, very few people host with static files nowadays.)””
I do like the respond to his comment, questioning his years doing SEO:

John replied politely to this, saying, “It’s always good to double-check what you run into online!”
Forum discussion at Reddit.