Data Feeds
CFD
Bar Building
We aggregate ticks to build bars.
In live trading, bars are built using the exchange timestamps with microsecond accuracy. This microsecond-by-microsecond processing of the ticks can mean that the individual bars between live trading and backtesting can have slightly different ticks. As a result, it's possible for a tick to be counted in different bars between backtesting and live trading, which can lead to bars having slightly different open, high, low, close, and volume values.
Delivery
Most live trading algorithms run on co-located servers racked in Equinix. Co-location reduces several factors that can interfere with your algorithm, including downtime from internet outages, equipment repairs, and natural disasters.
Live data takes time to travel from the source to your algorithm. The CFD data feed has a latency of 20-50 milliseconds. QuantConnect is not designed for high-frequency trading.