> Can you elaborate on this? What is the primary benefit of running 100-300 components vs a monolith specifically with a 12 person team?

> More directly, what's wrong with a monolith at the dozen person team size?

Great question. It's honestly a hard question to answer because the real answer requires tacit knowledge, but I'll try anyway because you asked. I'll link a couple articles of longer form writing that may help to answer as well.

The benefit ultimately is productivity. That productivity comes from autonomy, which comes from partitioning.

Each component can be worked, tested, and deployed on its own. We never need to spin up more than one at a time, which means any time we are working on our code, we are typically working on 1/400th of it, and we know we are because we have 400 separate GitHub repositories. We can't accidentally get peanut butter in our mayonaise. Each part is independently built and tested.

When it's time to upgrade Rails, we can upgrade one application. This is 1/20th of our Rails code. That's a smaller batch. We know from basic flow principles that (see: Principles of Product Development Flow, Lean, etc.) that small batches are better for productivity.

We rarely have merge conflicts. We don't do pull requests. We branch when we need to. We are often working on a brand new, never been deployed project. We don't have our tests running in CI. Our tests run in less than a second in most projects on our laptops. With those that have UI, our tests typically run in less than 30 seconds which include thorough Capybara (UI Interaction) testing.

When we are working in any application, we only need to consider its direct efferents when making a change to any interfaces it exposes. We can trace those changes through easily when we need to make them. Because we practice software design, we don't often need to make large sweeping changes, but when we do, we can do them methodically without disruption.

The "worst" part is that some things are tedious. But we can automate tedious things. We can invent around tedious things. We used to have to deploy 15 web applications any time we had a style change. Now we deploy one application that supplies the CSS for all our applications via SSI (server-side-include). If we need to deploy 70 back end components, we can script that (with manual verification at each step). We can even spread that out across a couple team members and do it as an ensemble. It takes about an hour to deploy everything. We maybe do this once a month or so (when something highly afferent changes -- and guess what, we structure our design so that afferent things change as infrequently as possible).

Most things we work on we work until they are "complete". That is, they rarely change after that. We have components that have been in production for 3 years and haven't been substantially touched aside from Ruby upgrades and the like. They are still perfectly in control.

The list goes on and on.

Here are a few articles, feel free to poke around the others and ask any follow up questions.

Partitions and Compositions: https://github.com/aaronjensen/software-development/blob/mas...

The Mythical Monolith: https://github.com/aaronjensen/software-development/blob/mas...