Meet the Developers - Mobile Software

Just last year, we launched t:connect® mobile app, designed to wirelessly upload pump data to our t:connect web application, receive notifications of insulin pump alerts and alarms, and provide a discreet, secondary display of pump therapy data. Now, we are seeking iOS engineers with Swift experience and Android engineers with Kotlin experience to help advance our mobile offerings.

We sat down with some team members to help you learn more about what it’s like to work on our mobile team, in case you’re seeking new opportunities and want to make an impact in the diabetes community.


Tim Sloncz, Manager, Software Engineer was hired to make the first mobile app version compatible with iOS. The recent release was a huge milestone for Tandem. Equally impressive are Tim’s contributions to growing the mobile team. Tim has created novel ways to bring the team closer and improve the mobile software development process and quality. His passion for writing quality software and delivering value to users drives the people around him to be better.

Jake McGhee

Jake McGhee, Android Software Engineer, helped develop our t:connect mobile app prior to its first release on the Google Play and Apple App Store. He is currently working on version 1.3 of the application, which addresses many bug fixes and includes a couple of new features for the app.

Courtney - 555 2

Courtney Langmeyer, iOS Software Engineer, is new to Tandem and made a significant impact already! She is currently working on the next generation of mobile app features and her teammates report that she brings great energy to the group.

Q1: Why use Swift and Kotlin?

Courtney: Swift is a native language for iOS development, which means we’re able to safely and effectively leverage the functionality. This is essential in our apps using Bluetooth® technologies where our focus is to communicate with the Tandem insulin pump securely and reliably. Swift is a powerful yet user-friendly language that produces high-quality apps which are even fun to develop! The Android team here at Tandem uses the Kotlin language which has many of the same benefits as Swift.

Tim: Swift is a modern language that maintains the speed of its predecessors while adding safety and expressiveness. I appreciate that we don’t have to sacrifice writing clean code to prevent undefined behavior. It is well adapted to building robust applications and very readable.

Jake: As an Android developer, I can only speak to Kotlin since Swift is used by our iOS developers. Android development can be done using either Java or Kotlin. But, as someone who has used both, Kotlin is definitely my preferred language. It offers a number of features that make writing code much cleaner, concise, and safer. Additionally, Kotlin has the added benefit that it is Google’s preferred language for Android app development, making it a safer choice for the app’s maintainability over time.

Q2: Is the use of these technologies what attracted you to join Tandem?

Tim: Swift is the future. It was still young when the mobile project started, and I think it says a lot about Tandem that we decided to commit to Swift at that time. We want to build the best products for our users and that means choosing the best technology for the job, even if it’s new.

Courtney: Yes! I love programming in Swift. It’s a very approachable language with endless capabilities. Before working at Tandem, I was curious about how Bluetooth® wireless technology worked with mobile apps, so Tandem was the perfect fit. It’s also very cool to learn about the technologies used by other teams here as well, such as the software used inside our insulin pumps. It’s great to work so closely with different development teams —there are many clever brains to pick!

Jake: Actually, no. What attracted me to join Tandem was the chance to use my technical skills to make, what I feel, is a positive impact in the world.

Q3: What do you enjoy most about working with these technologies?

Tim: I love being part of something that’s growing. It’s filled with pain points, but that’s what makes it exciting and keeps you pushing. I didn’t truly understand what it takes to maintain API excellence while working to evolve it, before following the evolution of Swift. It’s an inspiring project and there’s a lot to learn from it.

Courtney: I love mobile app development because it’s fun to code something on your computer and watch it come to life on your phone. More importantly, it’s fulfilling to know that the technologies created by our dedicated software and hardware teams are used to help so many people who live with diabetes. Our technologies are created to make lives easier, and that’s what I enjoy the most.

Jake: What I love most about application development is that mobile technology has pretty much become the primary way most people interact with computers nowadays. It’s an excellent feeling to be able to deliver software to our customers in a format that is easily portable and easily accessible.

Q4: How would you describe the team dynamic?

Tim: Open. All ideas are welcome and given attention. Code design, CICD, app features, team organization, it’s all fair game. We believe the best way to succeed is great ideas, no matter who they come from. Our goal is making users happy, and it really drives the team dynamic in a positive way.

Courtney: The team dynamic is so good that I’d much rather be in the office than working from home [because of COVID-19]! This team has some of the best talent, cooperation, and work ethic I’ve ever encountered while still maintaining a good amount of levity. It’s a respectful, positive, and productive atmosphere with a sense of humor.

Jake: I would describe the team dynamic as casual and playful. I think our team demonstrates well that it’s possible to deliver seriously good software development without taking yourself seriously 100% of the time.

Q5: What do you enjoy most about being on the mobile team at Tandem?

Tim: The drive. Trying to create medical device software quickly is a true challenge. It’s easy to maintain our drive and enthusiasm because the end goal is incredibly rewarding. We’re constantly growing not only in coding skill but teamwork and process excellence.

Courtney: When we were working in the office before COVID-19, it was probably the proximity of my desk to the soda machine in the break room, but it’s always the people! The mobile team isn’t huge and everyone keeps busy, yet there’s always room for supporting more junior people on the team such as myself. The mobile team is full of extremely competent people who all have diverse lives outside the office. I’m learning so much from being a part of this team.

Jake: Probably my team members. Everyone is very smart, friendly, and respectful which has made me really grateful to be working at Tandem.

Q6: What advice would you give someone who is interested in joining the team? Any tips for the interview process?

Tim: Keep learning. Medical device software is very rewarding and also very challenging. Take the extra steps to truly understand what your code is doing. Read blogs, Apple® docs, and Swift docs, but don’t stop there. Experiment, build excellent systems, and be able to explain them. Establish a good relationship with learning and the rest will take care of itself.

Courtney: It’s cliché, but just be yourself! Of course it’s important to dust off the ol’ textbook to make sure you can answer technical questions and do a bit of problem-solving, but it’s essential to show the team that you’re a person who we’d like to work with.

Jake: The ability to demonstrate good familiarity with the Android or iOS framework, teamworking/soft skills, and humility will all work in your favor.

If you or someone you know would like the opportunity to work alongside these individuals and to be part of the Tandem Team, please visit:


The information on the t:connect mobile app display may not be identical to the current status of your pump. Wireless uploads from the t:connect mobile app to the cloud-based t:connect web application require a compatible phone and an internet or wireless data connection. Uploads to the t:connect web application do not take place in real time and should not be relied upon by healthcare providers or caregivers for remote patient monitoring. Standard carrier data rates may apply.

Important Safety Information:

RX ONLY. The t:slim X2 insulin pump with interoperable technology is an alternate controller enabled (ACE) pump that is intended for the subcutaneous delivery of insulin, at set and variable rates, for the management of diabetes mellitus in people requiring insulin. The pump is able to reliably and securely communicate with compatible, digitally connected devices, including automated insulin dosing software, to receive, execute, and confirm commands from these devices. The pump is indicated for use in individuals six years of age and greater. The pump is intended for single patient, home use and requires a prescription. The pump is indicated for use with NovoLog or Humalog U-100 insulin. Users of the pump must: be willing and able to use the insulin pump and all other system components in accordance with their respective instructions for use; test blood glucose levels as recommended by their healthcare provider; demonstrate adequate carb-counting skills; maintain sufficient diabetes self-care skills; see healthcare provider(s) regularly; and have adequate vision and/or hearing to recognize all functions of the pump, including alerts. The t:slim X2 pump, and the CGM transmitter and sensor must be removed before MRI, CT, or diathermy treatment. Visit for additional important safety information.

t:connect mobile app: The t:connect mobile app is intended to be a secondary display for compatible Tandem Diabetes Care® insulin pumps and is capable of wirelessly uploading pump data it receives into the t:connect web application. The t:connect mobile app is not intended to control an insulin pump and is not intended to be a replacement for the information displayed on your insulin pump. Dosing decisions should not be made based on the secondary display device. The user should follow instructions on the continuous glucose monitoring system and insulin pump. This secondary display device is not intended to replace self-monitoring practices as advised by a physician.

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