Act I — What you stand on

Digital infrastructures focus on services rather than products, making it elusive to capture the essence of these services, especially in defining the fluid interactions between service providers and consumers. Promise theory is a little-known approach to interaction, though it has quite a few great thinkers behind it. Introduced by Mark Burgess and others, it is about how autonomous agents work together. It helped me a lot in getting a handle on various distributed systems. There was this project where we designed a scalable travel information system with what we now call microservices. We needed to describe how these parts work together. And there was a project that required lots of independent and autonomous social security agencies to work together on providing a service. In getting this from the drawing board to actual production, promise theory turned out to be a great tool. ...

Once we understand promises, contracts between agents now become really simple to express. They are a set of complementary conditional promises: “If you do this, I will promise that”. In our example this looks like the following. “If you promise to pay me, I will promise to bring you coffee.” “If you promise to bring me coffee, I will promise to pay you.” If one party does not keep its end of the bargain, the other party is free to withdraw from their part of the deal. Of course there is the complication that somebody has to deliver first: do you get coffee first, or do you have to pay first? This requires trust. As you are probably aware, both types of contract exist in real life. In fact you can find more complicated versions as well. ...