Why does the offline UUID differ from the official UUID?

With online-mode=false the server derives the UUID from the name alone. Worlds and inventories are tied to that UUID: switching online-mode changes the player's identity, hence their data.

What does the operator level mean?

From 1 to 4, it sets the allowed commands (4 = full rights, including /stop). The server uses op-permission-level (4 by default) for /op; here you set the level player by player. bypassesPlayerLimit lets the player join even when the server is full.

Minecraft 100% localFreeOpen access

whitelist.json and ops.json generator

Generate whitelist.json and ops.json from a list of usernames, with the offline UUID computed locally, no network or Mojang call.

Last updated: 10/9/2026

100% local processing — saved in your browser.

Documentation

Settings

No network request: official UUIDs must be pasted after the name.

File to generate

Offline server (online-mode=false): compute UUID

Players (one per line)

Format: Name or Name UUID. Name: 3 to 16 characters (letters, digits, _).

whitelist.json

3 / 3

[
  {
    "uuid": "5627dd98-e6be-3c21-b8a8-e92344183641",
    "name": "Steve"
  },
  {
    "uuid": "36532b5e-c442-3dbb-a24c-c7e55d0f979a",
    "name": "Alex"
  },
  {
    "uuid": "069a79f4-44e9-4726-a5be-fca90e38aaf5",
    "name": "Notch"
  }
]

Server installation guideNo server yet? Install it locally or on a VPS / dedicated server, ports and firewall included.

How to use whitelist.json and ops.json generator?

whitelist.json and ops.json hold name/UUID pairs. On an online-mode=false server the UUID is deterministic (MD5 of “OfflinePlayer:name”) and is computed here offline. On an online server the UUID comes from Mojang: this tool makes no network call, so you must provide it.

Choose the file to produce: whitelist.json or ops.json.
Enter one player per line: “Name” (offline UUID computed if the option is on) or “Name UUID”.
For ops.json, set the operator level (1 to 4) and fix any listed errors.
Stop the server, replace the file in the server root, then restart (or use /whitelist reload).

Read the full documentation →