Bounded context (DDD) is a good thing to start defining a service boundary with. But practically, it's just too coarse-grained to gain real benefits of microservices.

A service per bounded context means having multiple monoliths. That could be perfectly fine as there's no problem with a monolith. However, with microservices, we want to go further. A bounded context can contain multiple services.

So, what are the right boundaries for services?

I believe it's business capabilities. The fine-grained a business capability can be while still remaining autonomous the small can a service be.

A team per service or a team taking care of multiple services within one bounded context is a good practice. However, a single team should not be working across multiple bounded contexts.

Services should be orthogonal, that is, one service won't affect another.

How do you align your (micro)services?