Is there a CI service for bitbucket.org which allow managing build commands in a VCS file?

A few months ago Bitbucket launched Pipelines. Quoting from the link:

Continuous delivery is now seamlessly integrated into your Bitbucket Cloud repositories.

You may use it on free plans, but next year they will reduce the build minutes for free plans from 500 minutes to 50 minutes as told in this link.

Also, CircleCI is supporting Bitbucket. It has free plan with 1500 build minutes. It can be triggered by commit or tag in BB. https://circleci.com/