Ask HN: Best tech to process a real time data stream using low hw resources?

MercadoLibre is the Amazon of Latin America and has an open and official API (https://developers.mercadolibre.com/) where anyone can request data about the transactions made on the platform. For example, you can check in real time how many iPhones are being sold by a specific seller.

I've already developed a script on Python that uses Redis pubsub queue which interacts with node and d3js to output the data to a real time visualization.

I'd like to make a simple script that could run on a simple machine using the lowest possible resources for a third party to be able to run it.

What kind of tech stack would you use to do this? Any advice?