This software codebase began as a fork of prosody trunk (to be 0.9) merged with LW.Org's custom patches, initiating from August 7th 2012 (see first commit).

Being mainly based on Prosody a lot of Metronome's code is backport compatible, but as development keeps progressing the majority of the codebase has almost completely diverged from mainstream.

Differences from Prosody are, but not limited to:

The Pubsub API and wrapped modules, mod_pubsub and mod_pep
The MUC API and wrapper plugins
Pluggable MUC configuration
Pluggable Routing API
Core stack: Modulemanager, Usermanager, Hostmanager, Module API, etc...
More aggressive memory usage optimisations
Bidirectional S2S Streams
Direct TLS S2S Streams and XEP-0368 resolution
Dialback errors handling and "DB without DB" (XEP-344)
The anonymous auth backend (mod_auth_anonymous & sasl.lua ineherent part)
Included plugins, utils
SPIM prevention system
Hits/blacklist/whitelist based host filtering (mod_gate_guard)
In-Band Registration verification and account locking mechanism
The HTTP API
XEP-0252 support for BOSH's JSON Padding
Extensive Microblogging over XMPP support
Daemon Control Utility
It does have only one server backend being libevent and has a hard dep. on lua-event