# Data Flows In, Money Streams Out
Kazumi liked to be efficient. At the software company where s/he worked they were known for their efficient code. But they were most concerned about efficiency with time. They had important things to do. There was this Virtual YouTuber...

Everyday they took a tram to the office, and twice a day they didn’t want to wait. The tram company provided an app where you could see what time a tram was supposed to arrive. But that didn’t mean it would. Kazumi liked it when they walked out the door and the tram was pulling up when they arrived at the stop.

When an update to the tram app arrived they noticed that the tram company, which viewed itself as a public good, announced real-time tram telemetrics from each tram’s GPS. The data was available via an API. Nice.

It was time to scratch that itch. Kazumi decided to make a little app so they could always catch the tram with no waiting.

The first thing they discovered was that the real-time data wasn’t free. It cost half a cent per hour, which wasn’t much, but they hated subscriptions. They were an endless cash drain. Every time they looked in their crypto wallet they noted the money trickling out. For some of the streams, like their insurance and electricity, they didn’t mind because they were necessities. But the subscriptions for niceties, like music, were really irking.

Then they noticed that the tramline API had a Data-On-Demand option. This also would be paid for with a stream but the cost was metered in megabytes, not time. Aha.

Kazumi quickly built a web app with a dead simple user interface and a map. They accessed it with their browser, connected their wallet, and subscribed to the Data-On-Demand option. For the payment they setup a stream, filled in a variable flow rate, and opted to couple it to the incoming data stream. That way they would only pay when data was flowing.

Now, when they were ready to depart, they could check the app. It would fetch live data from the tram company. They would see the real-time location of the next tram down the street. And they would never have to wait again.

Since they only accessed the data twice a day the cost was minuscule. As the incoming data was coupled to the outgoing money stream the payment would practically cease when they stopped using the app. Likewise, if for any reason the real-time data halted, the payment would stop too.

To keep it simple, underwater the payment stream would continue in order to avoid having to approve a new transaction for each session. But the flow rate would reduce to near null during dormant times.

Now, that’s efficient! Kazumi moved on to more important stuff. Her name was Mio.

Mio Ookami – Source: Hololive Fan Wiki