The Obby protocol consists of commands sent between a client and a server. There is one command per line, possibly with a colon and some parameters. Note that integral parameters are sent in hexadecimal representation. Newline characters, colon characters and backspace characters are escaped to \n, \d or \b respectively.

When a client connects to a server, the server sends:

obby_welcome:8
net6_encryption:0

The obby_welcome command specifies what protocol version the server uses. The net6_encryption means that the server wants an encrypted connection. The "0" parameter means that the server requests encryption; the client would use "1".

The client responds:

net6_encryption_ok

The server sends:

net6_encryption_begin

At this point, the client starts a TLS handshake. After that, the connection is encrypted.

The client logs in:

net6_client_login:username:FF0000:globalpw:userpw

The parameters are the username, the user's colour, the global password, and the user's password. The two latter can be empty or omitted, when applicable.

If login and authentication are successful, the server continues:

obby_sync_init:1
net6_client_join:b:username:1:1:ff0000
obby_sync_final

The obby_sync_init command tells the client how many net6_client_join commands to expect. The fields of net6_client_join are net6 user id, username, encryption flag (in this context, always true), Obby user id, and Obby colour.

There is a difference between a net6 user and a obby user. A net6 user is a client that has connected to the server and performed a login. Each net6 user has a unique ID (11 in the example above, or hexadecimal b). A obby user is a user participating at an obby session and has also a unique ID (1). The difference is that the obby user is not discarded when the client exits. When he rejoins with the same name he is recognized as an already existing user and is assigned the ID that user had before. obby users are also serialized when storing an obby session.