I’d like to develop a mobile application with the following requirements:

• Each device sends each 10 seconds its location
• Each device should also show location of nearby devices in a map (basically the devices located between the map screen boundaries)

I think this is a pretty simple application, but I’m wondering what the best option is architecture-wise. I was thinking about using Kafka or some kind of message queue to publish and consume each location message, but the main problem I find is each device would be consuming a lot of messages that would be discarded right away if their location is outside the drawn zone.

Keep in mind that I’m designing the system with the goal of handling millions of devices at the same time (potentially), so I need to be able to process all the messages as fast as possible.