I’m currently testing using the free plan and have been logging some quotes (with timestamps) between Alpaca, yFinance, and just watching the stocks on my screen. I notice a significant latency between alpaca updating and yFinance (several seconds to almost 30 seconds in some cases). Does the API performance improve dramatically on the paid subscriptions or is the only real way to get ‘true’ real-time data to use a websocket connection?
Just for clarity, this is the endpoint I’m using:
@kcducttaper You asked “is the only real way to get ‘true’ real-time data to use a websocket connection?” The data via the REST endpoints is the same as that streamed with websockets and is available with about the same latency (approx. 10-20ms).
The issue is the free Basic market data subscription doesn’t provide full market real time data. For licensing reasons, it only provides a subset of trades and quotes from the IEX exchange real time.
The quote ‘latency’ you are seeing with the free Basic subscription isn’t really due to timing. Rather it’s because you are not seeing full market NBBO quotes - only those quotes which appeared on the IEX exchange. This makes them appear ‘lagging’.
To get full market NBBO quotes with the REST endpoints specify feed=sip. Without a paid Algo Trader Plus market data subscription you will not be able to query the most recent 15 minutes of data (it will return an error). By default, for convenience, the end parameter defaults to the most recent data one’s subscription can fetch. Omit end and you will get the most recent sip data available to your subscription.
Hope that makes sense.
Ok, that makes sense. So, they “perform the same”, but the free version is only pulling from the IEX exchange. Therefore, trades can be filled via other exchanges, but until another order is fulfilled via IEX, it won’t update using the free plan.
The Trader Plus plan streams data through the SIP which is what ALL exchanges pass through via regulations, so it *should* be updated just a handful of ms after a trade is executed from ANY exchange and *should* be the closest thing to a true ‘real time’ update from a total market perspective.