BitMEX uses industry-standard syntax to construct the contract ticket symbols.
|The first three letters of perpetual contracts refer to the home currency and which series it's in. For example, XBTUSD is in the XBT (Bitcoin) series and its home currency is XBT, so it starts with XBT.
| The second half of the contract symbol refers to what currency it's being quoted in. In XBTUSD's case, the quote currency is USD (US Dollar).
| The first three letters refer to which series the contract is in. For XBTN22, it's the XBT series.
| The 4th letter refers to which month code the contract expires in. You can use Futures Month Codes to see which month the code corresponds to. For XBTN22, the code is N which means it will expire in July.
| The numbers at the end of the symbol refer to the year the contract expires in. For XBTN22, it's 2022.