Everything S4OM does
Up to 12 players in one Sims 4 game, each controlling their own Sim. Here's exactly what stays in sync, what makes it hold together, and how it compares.
What stays in sync
Your Sims
- Movement, smoothed so nobody teleports
- Moods, needs and skills
- Relationships
- Inventories
- Traits, lifestyles, likes, dislikes and fears
- Careers, promotions, going to work
- Rewards store points
- Social Bunny followers, fame, reputation
- Occult ranks and perk points
The world
- Game clock and speed - the host decides
- Household money
- Calendar, holidays and festivals
- Parties, dates, weddings and other events
- Travelling together
- Small businesses
- Neighbourhood action plans and votes
- Trendi fashion trends
Building
- Buy mode: buying, moving, rotating and selling
- Build mode: the host's changes reach everyone with one click (Quick Save Re-sync)
- Newborns and adoptions arrive the same way, automatically
Playing together
- In-game chat
- Pop-ups go to the player whose Sim they're about
- Menus don't pause the game for everyone
- Joiners don't autosave mid-session
Made for groups
One cloud save for your group. Every save uploads automatically, and anyone in the group can host next time.
Every 10 seconds S4OM checks that everyone sees the same game - lot, speed, money, Sims, furniture - and quietly fixes what drifted.
Before you join, see exactly which mods and packs differ from the host's. Download the missing ones from the host in one click, or match their packs.
Skill Race, Mood Bingo, Social Butterfly and the team game Good Vibes - winners go on the Discord leaderboard.
A voice room for every online game, session recaps, game nights, your own private rooms, and Rich Presence with a Join button.
US and EU servers, join with a six-letter room code - no port forwarding, no IP addresses.
How S4OM compares
Based on each project's public pages, October 2026. "Not listed" means we couldn't find it on their pages - corrections welcome in our Discord.
| S4OM | S4MP | SimSync | |
|---|---|---|---|
| Players per game | 12 | 12 | 2 |
| Online with a room code | US + EU servers | Yes | LAN / IP only |
| Monthly price (1 / 2 / 4 players) | $10 / $15 / $20 | $11.90 / $18.90 / $25.90 | Free |
| LAN play free | Yes | Yes | Yes |
| Careers, calendar, events, businesses | Yes | Yes | No |
| Buy mode | Yes | Yes | Moving only |
| Build mode | Re-sync with one click | Live walls | No |
| Save loads automatically after a re-sync | One-click load button | Yes | No |
| Biggest save you can send | 600 MB | 300 MB | - |
| Shared cloud worlds | Yes | Not listed | No |
| Desync auto-repair | Every 10 seconds | Not listed | No |
| Download missing mods from the host | Yes | Not listed | No |
| Party games and leaderboard | Yes | Not listed | No |
| Discord voice room per game | Yes | Not listed | No |
| Pack toggling, unpaused menus, Rich Presence | Yes | Yes | No |
| Launcher languages | 8 | Several | - |
| Mac | In-game commands (launcher coming) | Yes | No |
| Changes the game's program files | No - script mod only | Yes, for build mode | No |
| Virus scan of every release, published | Yes | Not listed | No |
| Source code | Public (GPL) | Not listed | Public |
Why "changes the game's program files" matters: EA's mod policy covers script mods. Modifying the game itself falls outside it, under EA's User Agreement.
Not yet
- Live wall building while you build - walls arrive through Quick Save Re-sync instead
- Create a Sim and Manage Worlds together
- Living in separate households or travelling separately