Minecraft UUID Lookup

A UUID (Universally Unique Identifier) is the fixed, 128-bit identifier of a Minecraft Java account, written as 32 hexadecimal characters. With hyphens (8-4-4-4-12, the format used in whitelist.json, ops.json, and usercache.json) or without them (the Mojang API format), it's the same value; the tool shows both formats and accepts either as input. Servers use UUIDs for whitelists, ops, bans, player data (world/players/data/<uuid>.dat from version 26.1, previously world/playerdata/<uuid>.dat), and statistics. Plugins such as LuckPerms use them to associate permissions and data with players.

The fastest way is to enter the player name in the tool above. On your own server, you can also find UUIDs in usercache.json (names and UUIDs of players who have joined before) and in the log, which contains a line such as “UUID of player Notch is 069a79f4-44e9-4726-a5be-fca90e38aaf5” when a player joins. The command /data get entity @s UUID shows your own UUID as an int array. If the tool finds no match, check the spelling: a Java name contains 3 to 16 characters (some older accounts have shorter names) and uses letters A–Z without umlauts, digits, and underscores. The search is case-insensitive, and the tool still shows an offline UUID for names without a Java account.

No. You change your name in your profile on minecraft.net; your UUID stays the same. Your whitelist entries, permissions and player data are therefore preserved because servers associate them with your UUID. You should only update entries that still contain your old name.

If a server runs with online-mode=false, it cannot look up players through Mojang. Instead, it calculates a UUID from the name: the MD5 hash of “OfflinePlayer:<Name>” produces a version 3 UUID. For “Notch,” this is b50ad385-829d-3141-a216-7e7d7539ba7f, which is completely different from the real one. The calculation is case-sensitive. If you switch modes, player data suddenly becomes associated with a different UUID. Inventories, progress, and statistics will then be missing until you rename the files in the world folder to the new UUID (with the server stopped and a Backup made): from version 26.1, in world/players/data, world/players/advancements, and world/players/stats; in older versions, in world/playerdata, world/advancements, and world/stats.

Mojang removed past-name lookups from its public API in 2022; the old endpoint now only returns “Not Found”. This protects player privacy. There has been no official source for name history since then. Sites that still show previous names rely on their own incomplete data and are not reliable. This tool therefore only shows what Mojang publicly confirms: the current name for a UUID and vice versa.

No, this tool only works with Java Edition. Bedrock accounts are identified by their Xbox gamertag and XUID. On servers with Geyser and Floodgate, Bedrock players receive a UUID that starts with 00000000-0000-0000 and is derived from their XUID. The Mojang API can't look up these UUIDs.

The data comes directly from Mojang's public API (api.minecraftservices.com and the session server). It consists only of public profile data: name, UUID, and skin and cape URLs. A UUID is a public identifier, not a password, and no login is needed to look it up. To avoid Mojang's rate limit, we cache results for up to 10 minutes. A player who has just changed their name may therefore briefly appear under the old name. If Mojang reports a rate limit, try waiting a minute.

On a server in online mode, /whitelist add <Name> is enough; the server handles the rest. If you want to edit the file directly, copy the completed entry from the tool into whitelist.json, for example { "uuid": "069a79f4-44e9-4726-a5be-fca90e38aaf5", "name": "Notch" }, then run /whitelist reload. On servers with online-mode=false, the whitelist uses the player's offline UUID instead.