A symbol can be a trading pair or a margin currency.

Trading pair symbols are formed prepending a t before the pair (i.e tBTCUSD, tETHUSD, tDAPP:UST)

All pairs available in the platform are supported and can be either lowercase or uppercase.

The pair list is continuously growing, this websocket endpoint gives an up-to-date list:
wss://api.eosfinex.com/ws/

{ "event": "symbols" }

Response:

[ 
  0,
  "si",
  [
    { "pair": "tDAPP:UST", ... },
    ...
  ]
]

📘

NOTE

wss://api.eosfinex.com/ws/ currently doesn't support "symbols" event. The feature will be added with the upcoming release.
wss://api.eosfinex.com/ws-aux/ can be used to retrieve symbols list until then

The pairs that are available are the pair names that used on Bitfinex API.
Some pairs or tokens have different names on EOS mainnet.

A map is provided to convert tokens from Bitfinex to EOS mainnet format as part of the auth message. This is useful for converting pairs to and from EOS mainnet format, when interacting directly with eosfinex smart contracts.

{
  "event": "auth",  
  ...
  "map": {"MKR": "PMKR", "ETH":"PETH", ...}
}