Ethereum Names Service petitioned the United States Patent and Trademark Office (USPTO) over a trademark obtained by Unstoppable Domains. 

As ENS explained on the social media platform X, "In 2023 Unstoppable Domains (UD) obtained a patent for technology ENS Labs developed as open-source. Today, we petitioned USPTO to challenge the validity of that patent, and to ensure the web remains a collaborative space."

UD administers domain name and wallet services much like ENS. ENS claims UD patented "ENS's pioneering technology, directly leveraging our open-source innovations" and that ENS' contributions were even cited in the patent. 

"We gave UD every opportunity to avoid this battle: UD refused to open source the patent and refused to make any irrevocable pledges not to use the …