Lemmy itself is an open source software. It’s developed by a community, and was originally created by two developers. It does not make money, except from things like donations or patreon.
Lemmy instances are run by different members of the community. Various folks have answered ways that instances could make money but may not make money in any ways.
The Lemmy project also receives grants from NLnet (funded by the European Commission), whenever they finish milestone features. According to the developers, this was their main source of funding until very recently and are now asking for more donations.
Worth mentioning:
The Lemmy project also receives grants from NLnet (funded by the European Commission), whenever they finish milestone features. According to the developers, this was their main source of funding until very recently and are now asking for more donations.