by Leon Rosenshein

Lumpers and Splitters

Are you a lumper or a splitter? I like to think of myself as a splitter, finding boundaries and cleaning architecture as I go, but I’m not sure that’s always true.

Because to be a splitter, you need to have a deep(ish) understanding of the problem. And you can’t have a deep understanding of the problem, solution, and its internal boundaries until you’ve lived with both the problem and a solution for a while. Instead, the best you can do is put things that seem to go together, or at least get used together, in one place so you can find them next time you need them. That’s called v1 or the MVP.

Ideally you’ve done a good enough job on v1 and learned enough that it makes sense to continue. So you add to it. And as a new, successful product, you have some momentum and good will. You want to take advantage of that, so you make the small additions you need and put things where they seem to fit best. You still haven’t lived with it, so right next to that other similar thing seems like a good idea.

Lather, Rinse, Repeat. Suddenly you find yourself struggling to make the next change. Things aren’t fitting together well, and now that you’ve lived with it for a while, you recognize that the internal boundaries of your solution aren’t quite right. That’s OK. You’ve not only figured out the problem, you’ve got a good idea of what a better solution looks like.

So you dive in. Breaking things along clear boundaries. Tightening the bounded contexts and firming up the APIs between them. You find it’s much easier to make changes again. You’re a splitter, and you feel good about the code. Out of curiosity you check history to see who lumped it together that way. And it turns out that the lumper was you.

Lather, Rinse, Repeat