Mastodon has sent former President Donald Trump’s company a formal notification that it’s breaking the rules by using Mastodon’s open-source code to build its social network, named Truth. This news comes from a blog post by Mastodon’s founder Eugen Rochko, but others have previously pointed out that the organization behind Truth, the Trump Media and Technology Group (or TMTG), was violating Mastodon’s software license by not providing the source code for the site built on top of it. Trump’s group has 30 days from when the letter was sent to comply with the license or stop using the software, or it could lose the right to do so.
While Truth hasn’t officially launched yet, internet users discovered that a test version basically had the same interface as Mastodon, and that some of the code for the site was unchanged from the other social network’s code. By itself, that’s actually the intended use of open-source software — but as the Software Freedom Conservancy pointed out last week, apps or websites based on software that uses the AGPLv3 license have to in turn provide their own source code. According to the foundation that wrote AGPL, it’s meant to make the community’s software better: if you improve on something that someone else made, they should be able to benefit from your work like you did theirs.
As Mastodon and Rochko reiterated on Friday, though, TMTG hasn’t done that — it even went as far as to call its software “proprietary,” and seemingly tried to hide the fact that it was based on Mastodon. Now that the Truth has been revealed, however, TMTG will either have to rebuild it without using Mastodon’s code — a tall order, as bootstrapping a social network site isn’t particularly easy — or release its source code and change the terms of service.
It’s not the first time Mastodon has had to deal with, as Rochko puts it, “people so antithetical to [its] values” trying to build on top of its open-source platform. In 2019 Gab, a social network known for getting banned from almost everything due to how many toxic users it had, decided it would use Mastodon as a backend. Unlike that situation though, where Gab wasn’t really breaking any rules (at least regarding its use of the software), Truth is violating the AGPL by using Mastodon’s code in an unauthorized way. How TMTG will deal with the gauntlet now that it’s been thrown down (twice) is anyone’s guess, but it’ll have to respond unless it wants to open itself up to possible legal action.