Yesterday we had another discussion about architecture documentation and especially about decisions made about it. We came to a quick agreement, that the form makes no difference, but that there is a dire need for a way to see, why something is like it is.
One of the tooling suggestions here is ADR along with the adr-tools), which basically is just a helper for easy to handle markdown files, which can either be placed next to the code (for microservices) or into a dedicated repository. (for macro-architecture)
I am always in favor to have docs next to code, so the chance that:
Someone really reads it and more importantly
Keeps it up to date is better.
From my experience a wiki is just a collection of outdated files: Barely read; never updated.
Now that we have nice tools for our handiwork, we have to think about who writes docs and first and foremost when?
The latter is really easy, whenever a decision is made like which technology stack, which testing framework and so on, just write an entry.
And the answer to the first question? Probably you!