News of TikTok's achievement was reported by tech-security company Cloudflare.
The social media app made quite the climb this year, considering that in 2020 it was ranked No. 7 while Google sat at the top.
Some experts attribute TikTok's success to the pandemic as people look for more ways to occupy their time.
The app claimed 1 billion monthly active users in September.
After TikTok, the top domains this year were as follows:
2. Google.com
3. Facebook.com
4. Microsoft.com
5. Apple.com.
6. Amazon.com
7. Netflix.com
8. YouTube.com
9. Twitter.com
10. WhatsApp.com.