Pleroma: Less moving parts

What Is #Pleroma? ~ #ActivityPub

Pleroma is built on a lot less technology than Mastodon. To run a Mastodon instance, you need Rails, PostgreSQL, Redis, Sidekiq, NodeJS and – if you want search – ElasticSearch. For Pleroma, you only need Elixir and PostgreSQL, while still getting all the features. This simplifies installation and makes maintenance somewhat easier.”