Most of us know SOLID, and over the years have understood how useful it can get when we need to change.
Based on S & I parts of SOLID and from experience I used to design my HTTP RESTful services as fine-grained as I could. For example, in a simple contacts management system, I would create and expose these endpoints:
However, recently we were arguing over the granularity of our RESETful services, and a colleague proposed that we see Google's Contact as a sample and model.
To my surprise, I saw that they update contact in a very complex and coarse-grained manner, in one simple API.
We all have to admit that Google is the Internet's giant, and they don't do things without knowing what their doing.
If this was an arbitrary website, I wouldn't even consider them, and would probably argue that their developers are not familiar with the concept of breaking things down (divide and conquer/analysis/WBS/SOLID/...). But Google, is totally different.
Now I'm stuck at why they've done so, and which approach is more maintainable and better to create APIs. One big single API that updates/creates a complex model, or many small APIs that update/create small parts of that model.
This is a challenge for shopping carts, for contacts, for educational course management, for accounting articles and almost many more cases.
I know this might be subjective, but I'm searching to find objective reasons behind each approach, so that we can decide with more knowledge.