FAST isn't exactly a FIX encoding, it's a key-value encoding that can be translated to/from FIX. Roughly speaking, FAST is to FIX as BSON is to JSON. But star

FAST isn't exactly a FIX encoding, it's a key-value encoding that can be translated to/from FIX. Roughly speaking, FAST is to FIX as BSON is to JSON. But starting to use FAST today seems like a bad idea, because the largest publicly-known production users of FAST have already moved away from it (toward plain, uncompressed binary structs on the wire).