A System Level Integration practical I did as part of a team of 6 over a semester in my final year of University. We created an app controlled door lock. I was responsible for designing and implementing a RESTful API within the Flask framework.
The API has endpoints which are interacted with by both the iOS and Android applications and the hardware. The API uses a PostgreSQL database and is hosted on a Heroku cloud server. Considerable attention was given to managing version control, agile development and test driven development. A full write up can be seen in the project report linked above.