To get an idea of what functionality you can expect to be missing have a look through the issues. However, many things have been implemented and should work as expected. Please open an issue for anything where that's not the case and/or the server is reporting errors.

config.json

SpaceNinjaServer requires a config.json. To set it up, you can copy the config-vanilla.json, which has most cheats disabled.

skipTutorial affects only newly created accounts, so you may wish to change it before logging in for the first time.
logger.level can be fatal, error, warn, info, http, debug, or trace.
ircExecutable can be provided with a relative path to an EXE which will be ran as a child process of SpaceNinjaServer.
ircAddress, hubAddress, and nrsAddress can be provided if these secondary servers are on a different machine.
worldState.eidolonOverride can be set to day or night to lock the time to day/fass and night/vome on Plains of Eidolon/Cambion Drift.
worldState.vallisOverride can be set to warm or cold to lock the temperature on Orb Vallis.
worldState.duviriOverride can be set to joy, anger, envy, sorrow, or fear to lock the Duviri spiral.
worldState.nightwaveOverride will lock the nightwave season, assuming the client is new enough for it. Valid values:
- RadioLegionIntermission14Syndicate for Nora's Mix: Dreams of the Dead
- RadioLegionIntermission13Syndicate for Nora's Mix Vol. 9
- RadioLegionIntermission12Syndicate for Nora's Mix Vol. 8
- RadioLegionIntermission11Syndicate for Nora's Mix Vol. 7
- RadioLegionIntermission10Syndicate for Nora's Mix Vol. 6
- RadioLegionIntermission9Syndicate for Nora's Mix Vol. 5
- RadioLegionIntermission8Syndicate for Nora's Mix Vol. 4
- RadioLegionIntermission7Syndicate for Nora's Mix Vol. 3
- RadioLegionIntermission6Syndicate for Nora's Mix Vol. 2
- RadioLegionIntermission5Syndicate for Nora's Mix Vol. 1
- RadioLegionIntermission4Syndicate for Nora's Choice
- RadioLegionIntermission3Syndicate for Intermission III
- RadioLegion3Syndicate for Glassmaker
- RadioLegionIntermission2Syndicate for Intermission II
- RadioLegion2Syndicate for The Emissary
- RadioLegionIntermissionSyndicate for Intermission I
- RadioLegionSyndicate for The Wolf of Saturn Six
worldState.allTheFissures can be set to normal or hard to enable all fissures either in normal or steel path, respectively.
worldState.circuitGameModes can be set to an array of game modes which will override the otherwise-random pattern in The Circuit. Valid element values are Survival, VoidFlood, Excavation, Defense, Exterminate, Assassination, and Alchemy.