Zero interest rate architecture is a term I've loosely coined to represent software and infrastructure with some combination of:

* A general level of complexity far in excess of what's necessary to get the job done.

* Lots of expensive SaaS, often multiple pieces of it chained together in complex work flows. E.g. git commit to Github triggers build at service X and deployment to service Y authenticated by service Z and fronted by yet another thing and with logs sent to Datadog and... and... and... and...

* Despite the use of expensive SaaS the system still requires a lot of babysitting and manual administration, negating the point of using SaaS. Using expensive SaaS makes zero sense, full stop, unless it is saving you enough time and cognitive load to more than pay for itself.

Any static web site that costs more than $5/month kinda falls in this category for me. I picked on Vercel because JAMstack often fits these criteria.

I've seen companies spending thousands or even tens of thousands of dollars a month hosting static web sites. These could have been built on one workstation using a container or a VM and deployed at any static hosting service, but instead you have this complicated gitops workflow with multiple interlocking expensive services. The whole thing has dizzying complexity, tons of moving parts, breaks all the time, and costs a fortune.

The goal guiding these designs seems to be a desire to avoid doing things in house. In-house things are complicated and ad-hoc and expensive. So instead of doing things in-house you jam together a bunch of services... which ends up being complicated and ad-hoc and even more expensive. When it comes to complexity you've just moved the peas around on the plate, and you're spending more.

I call it zero interest rate architecture because the absurd cost of this stuff wasn't a big deal when VC money was basically free. "Just grow as fast as possible. You can optimize later."