Legacy Mojang Authentication
Minecraft 1.6 introduced a new authentication scheme called Yggdrasil which completely replaces the previous authentication system. Mojang's other game, Scrolls, uses this method of authentication as well. Mojang has said that this authentication system should be used by everyone for custom logins, but credentials should never be collected from users. For newer Microsoft accounts, see Microsoft Authentication Scheme.
Contents
Request format
All requests to Yggdrasil are made to the following server:
https://authserver.mojang.com
Further, they are expected to fulfill the following rules:
- Are
POSTrequests - Have the
Content-Typeheader set toapplication/json - Contain a JSON-encoded dictionary as payload
If a request was successful the server will respond with:
- Status code
200 - A JSON-encoded dictionary according to the specifications below
If however a request fails, the server will respond with:
- An appropriate, non-200 HTTP status code
- A JSON-encoded dictionary following this format:
{
"error": "Short description of the error",
"errorMessage": "Longer description which can be shown to the user",
"cause": "Cause of the error" // optional
}
Errors
These are some of the errors that can be encountered:
| Error | Cause | Error message | Notes |
|---|---|---|---|
Method Not Allowed
|
The method specified in the request is not allowed for the resource identified by the request URI | Something other than a POST request was received. | |
Not Found
|
The server has not found anything matching the request URI | Non-existing endpoint was called. | |
ForbiddenOperationException
|
UserMigratedException
|
Invalid credentials. Account migrated, use email as username. | |
ForbiddenOperationException
|
Invalid credentials. Invalid username or password. | ||
ForbiddenOperationException
|
Invalid credentials. | Too many login attempts with this username recently (see /authenticate). Note that username and password may still be valid!
| |
ForbiddenOperationException
|
Invalid token. | accessToken was invalid.
| |
IllegalArgumentException
|
Access token already has a profile assigned. | Selecting profiles isn't implemented yet. | |
IllegalArgumentException
|
credentials is null | Username/password was not submitted. | |
IllegalArgumentException
|
Invalid salt version | ??? | |
Unsupported Media Type
|
The server is refusing to service the request because the entity of the request is in a format not supported by the requested resource for the requested method | Data was not submitted as application/json |
Authenticate
Authenticates a user using their password.
Endpoint
/authenticate
Payload
{
"agent": { // defaults to Minecraft
"name": "Minecraft", // For Mojang's other game Scrolls, "Scrolls" should be used
"version": 1 // This number might be increased
// by the vanilla client in the future
},
"username": "mojang account name", // Can be an email address or player name for
// unmigrated accounts
"password": "mojang account password",
"clientToken": "client identifier", // optional
"requestUser": true // optional; default: false; true adds the user object to the response
}
The clientToken should be a randomly generated identifier and must be identical for each request. The vanilla launcher generates a random (version 4) UUID on first run and saves it, reusing it for every subsequent request. In case it is omitted the server will generate a random token based on Java's UUID.toString() which should then be stored by the client. This will however also invalidate all previously acquired accessTokens for this user across all clients.
Response
{
"accessToken": "random access token", // hexadecimal or JSON-Web-Token (unconfirmed) [The normal accessToken can be found in the payload of the JWT (second by '.' separated part as Base64 encoded JSON object), in key "yggt"]
"clientToken": "client identifier", // identical to the one received
"availableProfiles": [ // only present if the agent field was received
{
"agent": "minecraft", // Presumably same value as before
"id": "profile identifier", // hexadecimal
"name": "player name",
"userId": "hex string",
"createdAt": 1325376000000, // Milliseconds since Jan 1 1970
"legacyProfile": true or false, // Present even when false
"suspended": true or false, // probably false
"paid": true or false, // probably true
"migrated": true or false, // Seems to be false even for migrated accounts...? (https://bugs.mojang.com/browse/WEB-1461)
"legacy": true or false // Only appears in the response if true. Default to false. Redundant to the newer legacyProfile...
}
],
"selectedProfile": { // only present if the agent field was received
"id": "uuid without dashes",
"name": "player name",
"userId": "hex string",
"createdAt": 1325376000000,
"legacyProfile": true or false,
"suspended": true or false,
"paid": true or false,
"migrated": true or false,
"legacy": true or false
},
"user": { // only present if requestUser was true in the request payload
"id": "user identifier", // hexadecimal
"email": "user@email.example", // Hashed(?) value for unmigrated accounts
"username": "user@email.example", // Regular name for unmigrated accounts, email for migrated ones
"registerIp": "198.51.100.*", // IP address with the last digit censored
"migratedFrom": "minecraft.net",
"migratedAt": 1420070400000,
"registeredAt": 1325376000000, // May be a few minutes earlier than createdAt for profile
"passwordChangedAt": 1569888000000,
"dateOfBirth": -2208988800000,
"suspended": false,
"blocked": false,
"secured": true,
"migrated": false, // Seems to be false even when migratedAt and migratedFrom are present...
"emailVerified": true,
"legacyUser": false,
"verifiedByParent": false,
"properties": [
{
"name": "preferredLanguage", // might not be present for all accounts
"value": "en" // Java locale format (https://docs.oracle.com/javase/8/docs/api/java/util/Locale.html#toString--)
},
{
"name": "twitch_access_token", // only present if a twitch account is associated (see https://account.mojang.com/me/settings)
"value": "twitch oauth token" // OAuth 2.0 Token; alphanumerical; e.g. https://api.twitch.tv/kraken?oauth_token=[...]
// the Twitch API is documented here: https://github.com/justintv/Twitch-API
}
]
}
}
Note: If a user wishes to stay logged in on their computer you are strongly advised to store the received accessToken instead of the password itself.
Currently each account will only have one single profile, multiple profiles per account are however planned in the future. If a user attempts to log into a valid Mojang account with no attached Minecraft license, the authentication will be successful, but the response will not contain a selectedProfile field, and the availableProfiles array will be empty.
Some instances in the wild have been observed of Mojang returning a flat null for failed refresh attempts against legacy accounts. It's not clear what the actual error tied to the null response is and it is extremely rare, but implementations should be wary of null output from the response.
This endpoint is severely rate-limited: multiple /authenticate requests for the same account in a short amount of time (think 3 requests in a few seconds), even with the correct password, will eventually lead to an Invalid credentials. response. This error clears up a few seconds later.
Refresh
Refreshes a valid accessToken. It can be used to keep a user logged in between gaming sessions and is preferred over storing the user's password in a file (see lastlogin).
Endpoint
/refresh
Payload
{
"accessToken": "valid accessToken",
"clientToken": "client identifier", // This needs to be identical to the one used
// to obtain the accessToken in the first place
"selectedProfile": { // optional; sending it will result in an error
"id": "profile identifier", // hexadecimal
"name": "player name"
},
"requestUser": true // optional; default: false; true adds the user object to the response
}
Note: The provided accessToken gets invalidated.
Response
{
"accessToken": "random access token", // hexadecimal
"clientToken": "client identifier", // identical to the one received
"selectedProfile": {
"id": "profile identifier", // hexadecimal
"name": "player name"
},
"user": { // only present if requestUser was true in the request payload
"id": "user identifier", // hexadecimal
"properties": [
{
"name": "preferredLanguage", // might not be present for all accounts
"value": "en" // Java locale format (https://docs.oracle.com/javase/8/docs/api/java/util/Locale.html#toString--)
},
{
"name": "twitch_access_token", // only present if a twitch account is associated (see https://account.mojang.com/me/settings)
"value": "twitch oauth token" // OAuth 2.0 Token; alphanumerical; e.g. https://api.twitch.tv/kraken?oauth_token=[...]
// the Twitch API is documented here: https://github.com/justintv/Twitch-API
}
]
}
}
Validate
Checks if an accessToken is usable for authentication with a Minecraft server. The Minecraft Launcher (as of version 1.6.13) calls this endpoint on startup to verify that its saved token is still usable, and calls /refresh if this returns an error.
Note that an accessToken may be unusable for authentication with a Minecraft server, but still be good enough for /refresh. This mainly happens when one has used another client (e.g. played Minecraft on another PC with the same account). It seems only the most recently obtained accessToken for a given account can reliably be used for authentication (the next-to-last token also seems to remain valid, but don't rely on it).
/validate may be called with or without a clientToken. If a clientToken is provided, it should match the one used to obtain the accessToken. The Minecraft Launcher does send a clientToken to /validate.
Endpoint
/validate
Payload
{
"accessToken": "valid accessToken",
"clientToken": "associated clientToken" // optional, see above
}
Response
Returns an empty payload (204 No Content) if successful, an error JSON with status 403 Forbidden otherwise.
Signout
Invalidates accessTokens using an account's username and password.
Endpoint
/signout
Payload
{
"username": "mojang account name",
"password": "mojang account password"
}
Response
Returns an empty payload if successful.
Invalidate
Invalidates accessTokens using a client/access token pair.
Endpoint
/invalidate
Payload
{
"accessToken": "valid accessToken",
"clientToken": "client identifier" // This needs to be identical to the one used
// to obtain the accessToken in the first place
}
Response
Returns an empty payload if successful.
