Mastodon advertises itself as being a self-hosted project.
> Your *self-hosted*, globally interconnected microblogging community
https://github.com/mastodon/mastodon
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> I really do not think that "uses a reverse proxy in the front" and "has a database and a cache store" is a factor.
These things matter at scale, but the typical Mastodon instance comes nowhere near that scale.
A reverse proxy is relevant beyond O(10k) RPS; less than that, and a single process directly serving requests is more suitable. A separate database is relevant beyond O(10M) records; less than that, and any embedded DB, or, frankly, direct filesystem access with any encoding format, is more suitable. A caching layer is relevant at the next order of magnitude for both of those dimensions; less than that, and there's no need.
Mastodon should, by default, ship as a single binary, statically compiled, with no runtime language requirements, and should manage its data storage requirements directly to disk.
