At Mudrex, we use the best in class tech which helps us build fault-tolerant, highly scalable and concurrent systems which scale to 10000's of strategies running at a tick level in a cost-effective manner.
Our data collection systems constantly keep polling for data across exchanges and aggregate the tick data to the appropriate period. Once the aggregation is complete the aggregated data is consumed by individual strategies.
Each individual strategy has its own separate high capacity instance running. The strategy consumes the aggregated data and goes through with checking all conditions that are set up for buy or sell. If a buy or sell event is triggered then the strategy places an order with the corresponding exchange.
All orders get placed as market orders on the exchange and get executed as soon as the orders get filled.
On filling the order we deduct the balance from the user's account and send the user a notification of trade.