Where is my order? Is the app stuck? Even when everything else in an application is polished, the user experience might be far from delightful if the information on the screen rarely updates. Displaying up-to-date and often updating information on an application view inspires confidence in the quality of the product and the prospect of getting what you ordered. By Tero Laitinen.
our backend services push order tracking and group order state updates through the service consumer-events to consumer clients in addition to notifications. As a result, we can refresh client app views frequently and with low latency. Ensuring satisfying user experiences is our top priority, but our engineers also enjoy reduced server loads due to less polling, enabling us to better serve our rapidly growing user base.
Further in the article:
- Proof of concept: Delivering notifications using Socket.IO
- WebSocket-based state updates
- Client implementation considerations
By starting with a polling architecture, we could focus on core business features while offering an excellent order-tracking user experience. When we had fewer active users, clients could poll the state more often without straining the backend. Now we operate at a scale where relying only on polling is impractical. Maintaining user-specific PUB/SUB connections between a Redis instance and the WebSocket servers scales to many users. As an unexpected dividend of this technology choice, upstream services may use Redis transactions to implement message-triggering logic, for example, to skip duplicates. Good read!
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