Buildbot vs Heroku CI: What are the differences?

Buildbot: Python-based continuous integration testing framework. BuildBot is a system to automate the compile/test cycle required by most software projects to validate code changes. By automatically rebuilding and testing the tree each time something has changed, build problems are pinpointed quickly, before other developers are inconvenienced by the failure; Heroku CI: Fast, low-setup CI that’s easy to use. On every push to GitHub, Heroku CI runs your tests in a disposable Heroku app, so there’s never a wait time for a free CI worker. Tests run fast, on Performance dynos.

Buildbot and Heroku CI can be categorized as "Continuous Integration" tools.

Buildbot is an open source tool with 4K GitHub stars and 1.37K GitHub forks. Here's a link to Buildbot's open source repository on GitHub.

Pipefy, Landing.jobs, and Connected Bits are some of the popular companies that use Heroku CI, whereas Buildbot is used by Mozilla, Animoto, and Fetch Robotics. Heroku CI has a broader approval, being mentioned in 10 company stacks & 12 developers stacks; compared to Buildbot, which is listed in 7 company stacks and 6 developer stacks.