Is it legal to use MP3 encoding on my website?

Question

I'm currently developing a website that allows users to record voice notes and upload audio files and then share them to Twitter. I'm currently using the MP3 format, but it is patented. I wanted to use OGG but it has a really low compatibility, so I want to know more about MP3 licensing. I'm currently hosted in the United States.

Is it legal to share the audio content that users record/upload in the MP3 format?

I see that Tumblr allows users to upload MP3 files and also distributes them in MP3.

Twitter also uses MP3 in TweetDeck.

But I can't see them in the Licensed Companies in mp3licensing.com

Assuming there's no problem with the copyright of the content inside the MP3 (artists songs, etc) that users upload, is it legal to distribute the content in MP3 format?

Also, according to Wikipedia, all the MP3 patents expired in the European Union. Does that mean that it's not illegal there, and if it's illegal in the US I can host the files there just to avoid legal consequences?

Answer 1

Since April 23, 2017, MP3 is patent-free.

Answer 2

From the website that you linked to: "On April 23, 2017, Technicolor's mp3 licensing program for certain mp3 related patents and software of Technicolor and Fraunhofer IIS has been terminated." The licensing program has been terminated because the newest licensed patents have required, and the licensors feel they have no right (either moral or legally enforceable) to charge you for the use of mp3.

And it was always the case that the licensors allowed a reasonably high amount of use, so unless you are highly successful, you would have been allowed to use mp3 because the patent holders allowed it. And there is always the possibility of paying for a license.