System Design of a Mobile Trading App for a CFD Broker

Solution

The client requested Devexperts to design a system that reimagines their app and conforms to all their requirements. After analyzing them, we came up with the following:

The client’s existing app uses a mix of native-app code and cross-platform technologies. That can lead to severe issues with usability, performance, and maintainability. The mobile trading platform should be written using native technologies which are more reliable than cross-platform ones. That’s due to the trading UI’s nature, which constantly experiences load due to a permanent flow of quotes and chart data, as well as position and account metrics data. 

Therefore, we suggested a complete rework of the current client’s mobile app into new native iOS and Android apps. DXtrade Mobile, our mobile trading solution,  could serve as a basis for the new apps, so we wouldn’t need to develop an app from scratch. We also proposed taking the DXtrade Mobile code, forking it, and building custom apps on top. That would allow a swift implementation.

DXtrade Mobile also includes a mobile gateway, which is a server-side application feeding mobile apps with quotes, charts, account data — real-time and historic — and other content. In a clustered deployment, the mobile gateway acts as a load balancer.

Our implementation scheme also has a server-side product that enables easy integration with the broker’s ecosystem — in our product line, Gate45 plays this role.

The client owns 14 trading servers with real and demo trading accounts. The setup we suggested is flexible: we can change the number of trading servers in the future, without affecting the overall architecture and approach.

The Entire Process

We’ll backport the client’s existing app into the native mobile trading platform. The mobile gateway will serve as a central connectivity point for the mobile front-end, the client’s CRM, and Gate45. 

The solution requires the following high-level scope of work:

• Forking DXtrade Mobile’s code 
• Reimplementing the existing app’s functionality 
• Integrating with the client’s trading servers via Gate45

We propose designing all systems for high availability across instances. Front-end services should be deployed using a content delivery network, while back-end services use auto-scalers or containerization.

All systems are horizontally scalable. The middleware back-end sets up multiple connections to the client’s trading servers. That way, the system would still work even if the primary connection is down. The broken connections undergo restoration while the reserve connection is being set up.