How to share your world with friends; play it together, or pass it around when the host is offline

Every co-op world lives on one PC: the host's. Your friends only have it while that person is playing, so sharing your world with friends comes down to one of three things:

1. Play it together while the host is online. Free, built into the game, and gone the moment they log off.
2. Put it on a server that never logs off. Always there, and paid for whether anyone plays or not.
3. Pass the world between you, so whoever wants to play next hosts it from their own PC.

Most groups want the first on game night and the third for the rest of the week. Below is how each one works, where the first and the third go wrong, and how Checkpoint64 does both for a team: Checkpoint Connect gets everyone onto the host's server without a port forward, and a shared save lets the next person host when the last one is offline.

First, find the world

A world is a folder, sometimes only a file or two, on the host's PC. This is where the big co-op games keep theirs on Windows:

Every other game's save folder is on its own page. Checkpoint64 already knows all of them, but it helps to know what you're passing around.

Option 1: play together while the host is online

This is the default, and for plenty of groups it's enough. The host loads the world and everyone else joins through the game's own invite, usually from the Steam friends list or with an invite code. There's nothing to install and nothing to pay for.

Two things break it:

• The host logs off, and the world goes with them. Nobody else can play until they're back. If someone starts their own copy in the meantime, you now have two worlds, and only one of them survives.
• The game needs a port. Anything that runs as a separate server instead of a host button, like a Minecraft Java server or a game's dedicated server, needs a port forwarded on the host's router. On a flatmate's router, a student network or a mobile connection, or behind CGNAT, where the ISP shares one public address between many customers, there's usually no port you can forward. Minecraft Java's Open to LAN doesn't get around it either: it only reaches players on the same network.

Checkpoint Connect takes care of the port. It's new in Checkpoint64 2.0, in beta: the host shares the server running on their PC with their team, teammates join it through the app, and nobody touches a router. How to share a server with it is further down, and each game's page lists the ports its server uses: UDP 2456-2457 for Valheim, TCP 25565 for Minecraft.

Option 2: a dedicated server

A server keeps the world online around the clock, so anyone can drop in whenever they like. If your group plays across time zones, or twenty people expect to log in at 3am, that's what you want, and nothing further down this page replaces it.

For four friends who play on the same couple of evenings, it mostly means paying for a machine that sits idle most of the day, with someone on the hook for updates, mods and restarts. The long-form cost maths runs the numbers, and the dedicated server alternative guide has the side-by-side.

Option 3: pass the world around

The world is only files, so the do-it-yourself version is obvious. Whoever played last zips the folder and drops it in Discord or a shared drive, and whoever plays next copies it into their own save folder and hosts. That works until one of three things happens:

• Two people play separately. Each ends up with a world the other doesn't have, and whichever copy gets shared last quietly erases the other's evening.
• Nobody knows which copy is newest. A folder full of world-final-v2-jess.zip files is not a version history.
• The next host loads in as someone else. Some games write the host's character into the world itself. That one gets its own section, because nobody sees it coming.

The catch: whose character is in the world

Whether a world changes hands cleanly depends on where the game keeps characters.

• Valheim and Terraria keep characters apart from the world. You pick a character, then a world, so a friend loads your world as themselves. Pass the world folder and nothing else.
• Minecraft (Java) writes the host into the world. A world's level.dat records who hosted it, and whoever opens that world next is loaded as that player. Your friend spawns with your inventory, where you were standing, and when they quit, that character is saved over their own.
• Palworld keeps one fixed slot for the host. Whoever hosts takes that slot, so the next host plays the last host's character, while their own sits unused in the world's Players folder.

So when you pass worlds by hand, Valheim and Terraria swap cleanly. In Minecraft and Palworld, expect the next host to play as the last one.

Doing it with Checkpoint64

Checkpoint64 covers option 1 and option 3 for a team: Checkpoint Connect for playing live, and a shared save for taking turns. Both start the same way.

Once, to set up:

1. Everyone installs Checkpoint64 and signs in. It's free.
2. One of you creates a team and invites the rest, by their handle or, on the Steam version, straight from your Steam friends list. The invite turns up in their Invitations.
3. Add the game to the team's library for taking turns. Checkpoint64 has presets for 180+ games, so it already knows where the world lives. Leave auto-backup on.

Play together: Checkpoint Connect

This is for game night, when everyone wants to be in the world at once and the game runs a server you join by address: a dedicated server, a Minecraft Java server, anything that would need a port forwarded. If the game's own invites already get everyone in, you don't need it.

1. Start the game's server on your PC, the way you would anyway. Checkpoint64 shares a server that's already running; it never starts one for you.
2. Open your team's library and press Share a server. Pick the game from the list and its ports are filled in. For a game that isn't on it, pick Other game and type the ports its server listens on. Then press Share server.
3. Your teammates press Join next to your server in the same library. A Live tag shows beside the team's name in the sidebar while anyone is hosting.
4. They connect their game to the address Checkpoint64 shows them, one that starts with 127.0.0.1, as if the server were on their own PC.

Worth knowing:

• Directly when it can, through a relay when it can't. The two copies of the app connect straight to each other where the networks allow it, and through a relay where they don't, so CGNAT or a student network stops mattering.
• Only your team gets in. Our backend vouches for everyone who connects, and the host's app lets in only members of the team. Anyone who can change the team's saves can host; read-only members can join, but not host.
• A direct connection shows each of you the other's IP address. A team with read-only members or a Patreon link always goes through the relay, so the host's address is never shown.
• UDP and TCP, so it covers Minecraft Java and Terraria as well as Valheim and Palworld. Start Valheim's server without -crossplay: Iron Gate's server guide says a crossplay server can't be joined at a local or loopback address, and 127.0.0.1 is a loopback address.
• It's on every plan, Free included, and it uses none of your storage.
• It's in beta, and we can pause it for everyone if something goes wrong. While it's paused, the app doesn't offer it, and a server that's already shared stops with a note saying hosting is paused.

It pairs with the lock below: back the world up when you log off, and the next person can take the lock and host it from their own PC. The co-op page has the short version.

Take turns: the lock

For the rest of the week: option 3, without the ways it goes wrong by hand. The world sits in your team's shared library with its recent versions, and a server-enforced lock decides who can write to it.

Every time someone wants to play:

1. Claim the lock on the shared save. While you hold it, everyone else is read-only: they can still look and download, but nobody can upload over you. If someone else has it, you can take it over; they're warned, and it goes in the team's logbook.
2. Restore the latest version and host the world from your PC the way you always do. Anyone who's online can join you live, through Checkpoint Connect if the game needs a port.
3. Play. Auto-backup uploads a new version as the world changes, and every backup extends your lock.
4. Release the lock when you're done. Forget, and it lapses on its own.

Nobody waits for the host to come online, two sessions can't overwrite each other, and a bad session is one restore away. Checkpoint64 keeps the last few versions of every save (you pick how many, up to your plan's limit), and a version you pin is never cleaned up.

In Minecraft (Java), the next host plays their own character. When someone restores a Minecraft Java world from a team save that more than one of you can write to, Checkpoint64 frees the host slot in its level.dat, which is what a Realms download does too. The game then loads each player's own character, anyone who has never played in that world spawns fresh, and your character waits in the world's player files for the next time you join or host.

Check the storage first. A team's storage comes from its owner's plan: 20 MiB on Free, 1 GiB on Lifetime, 5 GiB on Pro. 20 MiB holds a Stardew farm, not a Minecraft world you've been building for a month, so for most survival worlds, whoever creates the team wants Lifetime. After the first upload, only the files that changed go up, so a big world doesn't cost its full size every session. Friends join for free, and there's no charge per person.

What it doesn't do

• It doesn't run a server for you. Checkpoint Connect shares a server that's already running on the host's PC and never starts one, so the world is online only while someone is hosting it. If your group needs it up around the clock, rent one.
• Nothing is restored behind your back. A newer version never lands on your PC until you restore it yourself.
• Everyone needs the app. Your friends install Checkpoint64 too, to join a shared server as well as to take turns. It takes a minute and costs nothing.

Games this fits

Any co-op game where the group shares one world: Minecraft, Valheim, Terraria, Palworld, Satisfactory, Factorio, Enshrouded, 7 Days to Die, Don't Starve Together, Sons of the Forest, Project Zomboid and V Rising, among others. The dedicated server alternative guide lists every co-op game in the catalog. Each game's page has its save folder and a link back here, and points to its server ports where we know them.

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Download Checkpoint64 or get it on Steam. It's free, and so is joining a friend's team.