Application Programming Interface (API) is your broker-dealer’s price data stream from its liquidity providers—usually banks—made available for custom programming. What sources it is composed of is usually difficult if not impossible to ascertain. No two are identical. Market makers use a composite of sources—that may even include its own micro-ECN. But given the enormous liquidity of the market, they do not usually vary a great deal. The exception is when market makers requote.
Most brokers offer their API as a separate service. A trader would use the API to drive third-party software or his or her own software program. On the flip side, third-party vendors offer their services using various dealers’ API. It can be confusing. If you use a third-party program for trading or even just for your charts, be sure it has a one-to-one or close correspondence with your brokerdealer data stream. Rolling your own integration is strictly for experienced programmer gurus. New traders should probably avoid third-party integration, also.
APIs are becoming less and less important as the integrated trading platforms now offer robust scripting languages. NinjaTrader’s NinjaScript is a subset of C# with many additional functions, objects, and libraries specifically designed for trading system development.
Most brokers offer their API as a separate service. A trader would use the API to drive third-party software or his or her own software program. On the flip side, third-party vendors offer their services using various dealers’ API. It can be confusing. If you use a third-party program for trading or even just for your charts, be sure it has a one-to-one or close correspondence with your brokerdealer data stream. Rolling your own integration is strictly for experienced programmer gurus. New traders should probably avoid third-party integration, also.
APIs are becoming less and less important as the integrated trading platforms now offer robust scripting languages. NinjaTrader’s NinjaScript is a subset of C# with many additional functions, objects, and libraries specifically designed for trading system development.
