OpenAPS was the first open source do-it-yourself artificial pancreas system, but is not the only one. You’ll learn more throughout the book about different DIY systems, their similarities and differences, and how they compare to various commercial systems.

At this point in time (spring 2019, at first writing of this book), there are estimated to be well over a thousand individuals worldwide who’ve chosen to use DIY closed loop systems over the last four years. People choose to use them for different reasons. Some people, like me, choose it for better and safer overnights with type 1 diabetes (you can read more about my story in the preface). Other people want to improve their A1c or time spent in range. Others want to reduce the cognitive or physical burden of work required to achieve their goals.

Some people may choose to continue using DIY, and others may choose to switch to a commercial system in the future. There will be a growing number of commercial closed loop options in the future, too. It’s exciting to have so many choices becoming available for people with diabetes. Just like traditional insulin pumps, though, they will all have different features and options, including different hardware and different algorithms. What works well for one person may not be the right choice for another person.

Whether we’re talking about DIY or commercial, it’s important to remember that a closed loop is not a cure for diabetes. These systems can work incredibly well, reduce burden and improve outcomes for people living with type 1 diabetes. But just like switching from MDI to an insulin pump, it takes work. There is a learning curve.

I’ve learned a lot from my personal use of OpenAPS over the last four and a half years. I’ve also learned a lot through helping, and observing, other people’s journeys in using DIY and more recently, also commercial versions, of artificial pancreas systems. I’ve spent a lot of time writing tips, tricks, and suggestions for people over the years. Although this content has been fully available online for years on my blog (, I recently realized that most people thinking about looping in various forms don’t have a single place to get a comprehensive picture about their technology options, the lessons the community has learned about the learning curve of switching from manual to automated insulin delivery, and a straightforward, plain-language explanation to guide them in making their choices.

My hope with this book is to share these lessons learned, and provide a guide to help people consider what’s important for them to choose the system that best works for them and their lifestyle. With the information shared in this book, I hope you’ll feel more informed, and empowered, in your choices related to closed loop technology, and have insight into what your learning curve will look like.