Monday, July 5, 2010

FIX Protocol Dictionary

In this post I will explore the phenomena of the online FIX dictionaries, why they appeared and gained popularity. Then I will explain the consideration we have been guided by when designing our own Fixopaedia.

FIX protocol organization releases specification in several formats, none of which in fact is formal (actually they also have recently adopted an online dictionary developed by the 3rd party):

  • Word documents for FIX
  • PDF for FIX
  • Schema for FIXML
What exactly are people looking for when going to online dictionaries? I would single out several types of requests:
  1. What do specific FIX field and its values mean?
  2. What fields are defined for specific message type?
  3. What other messages are relevant to specific message type?
Basically this means that a perfectly organized specification enables the user to easily find the answer to his questions without even having the specification stored somewhere on his computer. Word and PDF documents are definitely not the best format for such people.

So let's analyze what should user do to find answers to the questions above.

Case 1.
User searches for the word "OrdType" and finds full definition of the corresponding field e.g. the way it is done here:

Case 2.
User searches for the words "New Order Single" and finds full definition of the message e.g. the way it is done here:

Case 3.
User wants to browse all messages related to the order so he searches for the word "Order" and finds the list of messages e.g. the way it is done here:

Obviously there are users that prefer to navigate rather than search, so this functionality must also be available.

Does all the above mentioned mean that Word and PDF formats of specification are not useful at all? Of course not. Those formats are perfectly suitable when you study FIX from the beginning or when the new version of the protocol is released.

Designing FIXopaedia

So what are the key concepts we followed while designing FIXopaedia?

  1. Access to the information. User should be able to find information with minimal effort.
  2. Effective layout. Present as much information as possible on the same screen i.e do not waste screen space.
  3. Navigation. User should benefit from hypertext as much as possible easily navigate between relevant fields and messages. At the same time data must be structured so the user is able to navigate from highest to the lowest level.
  4. Compactness. User must be able to get all required information in one place without extra navigation e.g. message name and type, field name and type (including possible values), required attribute, short description and corresponding FIXML tag - everything must be shown on the same page.
  5. Completeness. Maximum information available in standard must be present in the online FIX dictionary.
  6. Speed and lightness. Do not overload page with heavyweight pictures, scripts or server side processing. The display time must be unnoticeable as well as search time.
  7. Searching facility.
  8. Non-aggressive pretty looking color schema.
So this was an intent, which resulted in FIXopaedia. Do you think we reached the goal? Do you think we missed some must-have or nice-to-have features? Feel free to comment.

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