In my open source projects (e.g. my Cluecumber Maven Plugin for Cucumber reports), I usually keep all the code in GitHub monorepos. This way, multiple projects that belong together are easier to maintain because you only need to checkout one repository instead of many.
A little disclaimer first: this is not about bragging! I would just like to take the oportunity to tell you a little bit about my journey into test automation. In fact I presented this during the Nordic Testing Days 2019 conference in Tallinn, Estonia.
The slides of my presentation "The Road To QA – From Developer To Test Automation Engineer" for Nordic Testing Days 2019 are now online.
This is my talk from SeleniumConf 2017 Berlin about how the QA and test automation teams were set up for trivago's main product, how they used to work, and how we gradually introduced the test automation topic. This is not mainly about the technological aspects and challenges but more about how and why we established certain processes.
I was part of a panel discussion about testing horror stories at Selenium Conference Berlin 2017.