When a player joins a place, how does Roblox decide which server the player goes to?

Say there is a game with a start place (Place A) and another place to teleport to (Place B), each with a Max Player Count of 50. There are no private servers for the game.

  1. When the first player joins, a server will be created for Place A. Is it guaranteed that the next 49 players will join that same server? If not, what would happen and why?

  2. Assuming the first question is true, then if 55 players join the game there will be one server with 50 players (Server1) and another with 5 players (Server2). If a player from Server1 leaves the game, and then a player joins, which of the following is true:
    I) Player joins the server with the fewest players (Server2)
    II) Player joins the oldest server that isn’t full (Server1)
    III) It’s random
    IV) Something else (please explain)

  3. The two questions above are for a player joining the game (Place A). Are the answers to these questions the same they were about a player joining Place B from Place A?

  4. Is there a way to keep track of your game’s place’s servers such that you could implement your own player server balancing logic?


This should answer most of your questions.


It depends on what option you picked in your place’s settings.
Configure Place > Access > Server Fill


Roblox optimizes server fill for me:

  • Best social gameplay experience (no idea how this works, sorry).

Fill each server as full as possible:

  • All servers will fill up in order (all players that would be placed in server A, but when it is full then all players that would join past this point will be placed in server B).

Customize how many server slots to reserve:

  • Specific number of server slots, not decided by Roblox (self-explanatory).

Official post by Roblox staff that is about this topic: Updates to Preferred Player Count

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Unfortunately it does not.

“Roblox optimizes server fill for me”: this doesn’t answer how they are optimized, it just says they are. The tooltip doesn’t provide any additional info.

“Fill each server as full as possible”: this doesn’t answer my question about the order in which servers are filled if for example 2 servers exist and they both are not full.

“Customize how many server slots to reserve”: Say I chose 2 for the server slot amount, the questions about how Roblox decides to fill them are not answered by this.

I don’t believe Roblox has released this information.

Fill the first server, then move onto the next, etc

Same as the first option, but reserve a certain amount of slots for certain people and don’t allow Roblox to automatically load random people into those reserved slots.

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Thanks, that article was helpful. They are still a little vague on the details of how exactly this works, but maybe the specifics aren’t known to the public.

Then aren’t the reserved slots essentially private servers? How would a player get to those reserved slots if there are no private servers?

It works like this:

Example Scenario:
Total Per Server: 5
Reserved: 2

This is the one server.

Player A, Player B, & Player C join. They are not related to the developer.
Developer A joins.
Player D tries to join, but he can’t since the only spot left is a reserved spot.

So what you’re saying is a “slot” is space for a player, and the developer of a game can somehow grant themselves (and people of their choosing) a special roleset such that they take a reserved slot?

Yes, that’s exactly what I’m saying. I don’t exactly remember how the slots are chosen, but I believe it’s the developer & their friends. Let me check real quick.

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OH reading that option back I think they reserve slots for the friends of players in the game so that if a friend joins them they wont run into a full server because there will be a slot reserved for them. It wouldn’t make sense if it was only for the developer as that wouldn’t help the majority of the user base.

But in the official announcement it says this:

The tooltip and announcement are conflicting and this is quite confusing.

I’m also a bit confused about the Customize how many server slots to reserve option. But with a little bit more digging, I think I got it!

On the article, it states that you can specify how much friends can join you in the server that you’re in. But let me give you an example to help make it less confusing: Imagine that there is a server with a player list of 10. If you enable the Customize how many server slots to reserve option, there’s actually a new option that pops up!


From my understanding, Only 5 random people could join your server. And the 4 slots are reserved for your friends. But I’m not sure if this reserve thing is only for the creator, or for everyone as well. I may be wrong, but that is what I understand right now.

(Edit: Oops, looks like y’all already figured it out.)

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I think that makes sense actually. “Roblox optimizes server fill for me” chooses a number of server slots to reserve based on some internal logic (“optimizes”), while “Customize how many server slots to reserve” is the same thing as the first option but you get to pick a set number of slots.

The more I know about these options, the more I feel they are describing how one server is filled, and not how player server balancing works (which was the focus of my original questions).


Yea it clicked for me, thanks for the help though. As I said in the other response, I think these server fill options describe how one server is filled vs how player server balancing with multiple servers work (which was the focus of my original questions).

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