What a Realm is
This page compares Java Edition Realms with running your own server. Bedrock Realms are a separate service with their own subscription plans and their own limits, and nothing below describes them.
The Minecraft Wiki describes Realms as "an official subscription-based server hosting service". You subscribe from inside the game, Mojang hosts the server, and everything behind it is Mojang's to run. In Java Edition a Realm runs the official vanilla server software, the server.jar Mojang publishes, so the game on a Realm is the game as shipped. The wiki is equally plain about who it is for: Realms "are not intended for large public servers, but for groups of friends or as a family server".
A hosted server is that same official path turned inside out. Mojang publishes the Java server software free of charge, and the wiki's Server page says players "can host servers using the free server software or Minecraft Realms". When you rent a server, that software (the vanilla jar, or Paper, or another fork) runs on a machine whose files and settings are yours to touch. Every decision Mojang makes on behalf of a Realm subscriber becomes an operator decision you make yourself.
Player limits
A Java Realm holds up to 10 other players at the same time, plus the owner. The wiki states it directly: "In Java Edition, a Realm can have up to 10 other players", and the Realm keeps "a player slot reserved for the owner only". That ceiling is part of the service, not a setting you can raise.
On your own server the ceiling is a line in a file. The max-players setting in server.properties ships at 20 and can be raised or lowered; the server.properties reference lists it alongside the other lines a small server actually touches. For a group of four, ten slots is roomy. Past ten friends at once, a Realm is already too small and a server you control is the only one of the two that grows.
Mods and plugins
The wiki's Java Edition limitations list is one line long and leaves no room: "Mods and plugins cannot be installed." There is no plugins folder on a Realm, no mods folder, and no way to add one. If what your group wants is an economy plugin, a permissions plugin, or anything else from the plugin ecosystem, a Realm cannot host it.
Plugins need server software you control. The Paper versus Vanilla versus Spigot versus Purpur comparison covers how those differ and why Paper is the usual answer when plugins are the point, and the plugin installation guide walks the drop-in-the-folder-and-restart routine. Mods are the same story with a different loader: a Forge modpack needs a server you run, which the Forge modpack guide covers.
World control
Bringing an existing world is supported on both sides. On a Realm, "a world slot on the Realm can be replaced by any local world of the Realms owner", and a Realm stores up to three worlds with one active at a time. Your singleplayer world can become the Realm's world from inside the game.
On your own server the world is a folder on the machine. The upload guide covers moving a singleplayer save onto a server by naming the folder in level-name, and because the files are yours, the same copy-them-anywhere routine moves the world between servers and hosts later. What a Realm offers instead of files is a short owner menu: the wiki lists what an owner can change, and it comes down to the Realm's name and description, the server region, which world slot is active, and per-player permissions. A server you control exposes all of it: server.properties, plus the whitelist, op and ban commands the access-control guide documents.
Backups and settings
On a Java Realm, Mojang creates a backup every few hours while players are online. The owner can put a world slot back to the state stored in any of those backups, and each backup can be downloaded to your device as a singleplayer world, which is also the way out if you ever decide to leave. You do not schedule these backups or store them anywhere yourself; the service handles them.
On your own server, backups exist if you make them. The backup checklist is the routine: stop the server, copy the world folder, and occasionally prove the copy opens. Nobody takes one for you.
Settings follow the same shape. The wiki says "worlds on Realms cannot use experimental settings", and that includes uploaded worlds. A Realm must also always use the latest stable or development version of the game, so you cannot sit on an older release waiting for something to catch up. A server you control runs the version you put on it, and changes versions when you decide to.
The comparison at a glance
| A Java Realm | A server you control | |
|---|---|---|
| Runs on | Mojang's hosting, subscribed to in-game | Server software you choose, on infrastructure you rent |
| Players at once | Up to 10 others, plus the owner | A setting: max-players, 20 as shipped |
| Plugins and mods | Cannot be installed | Supported by the software you pick (Paper for plugins, Forge for mods) |
| Your world | Uploaded as a local world into one of three slots | A folder on the machine, copyable anywhere |
| Backups | Created by Mojang every few hours while players are online | Whatever you set up |
| Settings and version | A short owner menu, no experimental settings, always the latest version | server.properties and config files, your version choice |
How to choose
If two to four friends play together, nobody has asked for a plugin, and the world's settings have never needed touching, a Realm may be all the group needs. It is the lowest-effort way to keep a shared world online, and the every-few-hours backups mean the world outlives nobody remembering to copy it.
The moment any of these is true, the answer tips to a server you control: someone wants a plugin or a mod; you want a say over the version or the settings; the group is larger than ten players besides you; or you want the world files in your own hands on a schedule you set. Those are precisely the things a Realm, by design, does not hand over. If the software choice is the part you are weighing, the friends-server guide walks the Paper-versus-Vanilla decision for a small group.
Where to read next
The software comparison covers Paper, Vanilla, Spigot and Purpur, the plugin guide covers installing plugins on Paper, the upload guide covers moving a world onto a server, the access-control guide covers the whitelist and the op and ban commands, and the backup checklist covers the routine every operator should have. Hosting notes for the game are on the Minecraft availability page.