Premium auto-login

How a premium account is verified, and which UUID it ends up with.

A premium player connects, sees the vanilla “Encrypting…” screen for a moment, and lands in the world already logged in. No command, no password.

How it is verified

Which mechanism does the verifying depends on your setup — rLogin detects that at startup and reports it in the console.

Standalone

On a single online-mode: false server, rLogin does it itself:

1. Hold the login

   The LOGIN_START packet is intercepted and held before the server processes it.

2. Ask Mojang about the name

   Is this a real premium account at all? If not, the exact same packet is re-injected and the login continues as if nothing happened. Cracked players see zero difference.

3. Run the encryption handshake

   rLogin sends an encryption request. The client contacts Mojang on its own and answers — this is the vanilla client’s standard behaviour for this exchange, not something rLogin induces.

4. Confirm with hasJoined

   Mojang confirms that this client owns the account, not merely that the name exists. Only now is the player considered premium.

5. Apply the real identity

   The UUID and signed skin Mojang returned are handed to the server, the same way a proxy would forward them.

This is the setup that requires PacketEvents.

Behind a proxy

Velocity already verified the account before the backend saw the connection, and forwarded the real profile with it.

rLogin recognises this without any cross-process syncing: it compares the UUID against the one the server itself would have generated for that name offline. If they differ, somebody already did the verifying.

online-mode: true

The server or proxy did it. Every connection is premium by definition and nobody is ever asked for a password.

This only runs under auth-mode: online. On auto or offline rLogin refuses to start with online-mode on, because it would be quietly turning away the players those modes exist for — see what online-mode has to be.

A plain “is this name premium?” API check is not verification — anyone can type a premium name. rLogin never treats a name lookup as proof on its own; it is only ever used to decide whether the handshake is worth starting.

uuid-type

Which UUID players end up with. Only applies to a standalone server — behind Velocity the identity is decided before rLogin ever sees the connection.

premium:
  uuid-type: real

real — the default

Verified premium players join with their real Mojang UUID; everyone else keeps the offline one.

This is the only mode where “premium Steve” and “cracked Steve” are separate accounts, and where your other plugins — permissions, economy, bans — see the same UUID they would on any online-mode server. It is also what makes switching to online-mode: true later a non-event.

cracked — keep an existing offline world

Everyone gets the offline UUID derived from their name, premium included. Auto-login still works exactly the same.

Use this when you already have an offline-mode world and player database that you want to keep working untouched. offline is accepted as a synonym.

random — one identity across both

A random UUID generated the first time each name connects, and reused from then on, for premium and cracked alike.

Lets a player move between a premium and a cracked launcher without losing their data. The trade-off: a non-offline UUID no longer proves anything, so only the cryptographic handshake counts as verification under this mode.

Changing uuid-type on a server that already has players changes who they are — they will look like brand-new players to every other plugin. Use /rlogin changeuuid to carry an account across if you do.

Bedrock players

Bedrock players arriving through Geyser/Floodgate were already verified by Microsoft, so they are treated as premium and never asked to log in.

bedrock:
  floodgate-auto-login: true
  prefix: "."

prefix must match username-prefix in Floodgate’s own config.

When Mojang is down

premium.api-failure-policy decides. fail-open (the default) treats the player as cracked and asks for /login — the server stays up. fail-closed refuses the connection until Mojang is reachable again.

Results are cached for premium.cache-ttl-minutes (60 by default), so a brief outage often goes unnoticed for players who have connected recently.

Turning it off

premium:
  auto-login: false

Or, more thoroughly, auth-mode: offline — which also removes the PacketEvents requirement, because nothing is checked against Mojang at all.