Tools
whitelist.json and ops.json generator
Paste names and get a ready whitelist or ops file with the right UUIDs. For an online-mode server the UUIDs come from Mojang; for an offline server they're computed from the name exactly as the server does it.
whitelist.json and ops.json
We look up account UUIDs at Mojang: the names go there through our server and aren't stored.
One per line or comma-separated, up to 50.
Add names and the file appears here. For an online-mode server, press "Look up UUIDs at Mojang".
How whitelist.json and ops.json work
The server knows players by UUID, not by name. Each whitelist.json entry is a uuid and a name; ops.json adds level, the permission level, and bypassesPlayerLimit. The format is described on minecraft.wiki.
The UUID depends on the mode. With online-mode=true it's the Mojang account's UUID; on an offline server it's the UUID the server computes from the name. Mix the modes up and the player fails the whitelist even though their name is in the file.
The files live in the root of the server folder. On a running server, run /whitelist reload after editing whitelist.json. Ops always pass the whitelist, so there's no need to add them. white-list=true in server.properties turns the list on, and enforce-whitelist=true kicks anyone no longer on it.
A whitelist keeps strangers out, not your own players with cheats. That takes an anticheat: DGuard, the best anticheat for a modern Minecraft server, is free for servers up to 30 players online.
Read in the knowledge base
FAQ
What's the difference between whitelist.json and ops.json?
whitelist.json is who may join while the whitelist is on. ops.json lists operators: players with command permissions, at a level from 0 to 4.
Why can't a player in whitelist.json join?
Usually the UUID is for the wrong mode: an offline server needs the offline UUID, an online one the account's UUID. Also check that /whitelist reload ran after the edit.
What operator level should a moderator get?
It depends on the job. Level 1 only bypasses spawn protection, 2 opens more commands and command blocks, 3 adds player management, 4 is every command, server management included. Fine-grained permissions are easier with LuckPerms.
Can I add a player without the file?
Yes: /whitelist add <name> and /op <name> on a running server. The generator helps when there are many players or the file has to be ready before first start.
The tools are free. So is anti-cheat protection
DGuard — the best anticheat for a modern Minecraft server — catches all 47 cheat types in our comparison; the nearest rival, Intave, catches 27. Free up to 30 players online, with the same protection as on paid plans.