Difference between the FIX and FAST protocols? [closed]

Question

Could anyone explain what the difference between FIX and FAST? When should one use FIX, and when should one use FAST?

Figwort

Answer 1

From an equities trading perspective, FAST is more widely used for market data dissemination, where message rates are much higher. FIX is the protocol of choice for interoperability between firms, and often internal systems as well, although different implementations can vary widely in the specific messages & attributes used.

Brokers and trading venues will generally offer order entry via some flavour of FIX, and offer a complementary native binary protocol for the most performance-sensitive clients or specialised features. The FIX interface is often just a wrapper around the native one, with an more limited set of message types and parameters.

A good example of this is the London Stock Exchange, with offers FIX 5.0 for order entry, along with their own low-latency native protocol. For market data they offer a combination of FAST and ITCH, although even using FAST, the full-depth market data feed isn't available to subscribers, and requires ITCH, as described here

Dorotea

Answer 2

FAST(FIX Adapted for STreaming) is FIX only, but customised to send across data more quickly, because of the huge increase in volume of data transferred in today's markets, as compared to normal FIX implementation. This should clarify a bit more.

Neurogram

Thank you..the document is really good! :) – Figwort

The link mentioned as clarification is broken – Wholehearted

Answer 3

FIX is text based protocol where all information encoded in tag=value format and delimited using special character:

'....35=X|55=EUR/USD...'

This mean that even decimal data will be send as text e.g. 1000000(which give you 7 bytes instead of 4 if code as binary).

FAST is solution to resolve this overhead. It based on concept of templates where described bytes order, sizes and meaning.

Arnoldarnoldo