Sincerely, the mobile dating app we built in a weekend

Have you ever had an idea scribbled on a notepad? It is time to take action! We love the adrenaline and fast paced development environment of Startup Weekend and decided to model our own project after it. Startup weekend is an event where you build a business and prototype within 54-hours.

Messaging on dating apps can be extremely stiff and painful. Texting feels a bit like a game--I prefer calling. When hearing a voice or a laugh, it feels genuine; it feels real. The experience is significantly different. So why not build a dating app centered around calls? Why not revitalize the practice of making phone calls in modern dating?

These thoughts inspired us to take initiative and create that solution. We challenged ourselves to build “Sincerely”, a fully functional mobile application focused on phone calls--over the course of one weekend.


We desired more than just a simple prototype — we desired building a real product.

The rules were simple. Complete a functional mobile application and deploy it to the app store by the end of the weekend. Start at 4:00 PM on Friday and finish by Sunday at 9:00 PM. Rules are set. Let’s go!


We kicked off the initial hours with a discovery phase. We asked qualifying questions about the product. What are the challenges we face with existing apps? Do most people face these same problems in online dating? Are phone calls outdated? These were questions which required feedback from potential users in order to validate our concept. We surveyed friends, families, and online dating customers. Dissatisfied customers expressed their frustrations with current modern dating applications. A market exists.

Product Development

We knew that the only way we could finish building an application in one weekend was to keep it simple. In other words, we needed to determine the core features that went into our MVP (minimum viable product). We agreed on the following:

  • Swiping (Similar to Tinder)
  • Matching
  • Calling
  • Profile

To begin our design process, we used a technique from the Google Design Sprint known as the “Crazy 8” method. This is a process in which you sketch 8 different user experiences in quick 30 second intervals. The process forces you to find creative high-level solutions to difficult problems.

“Keep it simple!”
Example: Crazy 8 Sketch

With this exercise, we were able to determine a suitable user experience. We agreed that a “tinder-like” interface would be easy-to-use and familiar. Users would swipe on potential matches and be granted the ability to make phone calls upon matching.

With the foundational user experience defined, we were now ready to start dividing and start working on the tasks. Next up is the fun part — the building.


Next is the Aesthetic. We believe there exist people seeking more than just surface-level dating. People who believe in love and romance. It was important that the people we attract were looking for genuine, authentic relationships. The branding revolved around a traditional hand-drawn aesthetic. Our designer drew the assets by hand and generated the digital images using Adobe Illustrator. We used design tool Sketch to create the user interface.

Let’s Code

We have built dating apps before, which gave us an advantage. Our reusable code base drastically reduced development time. Furthermore, the code was already divided in a manner that allowed us to work independently and efficiently. We held 2–3 hour development sprints, followed by 10-minute walks to discuss the progress. Having a clear deadline helped us focus on getting the work completed on time. We were resolved to deploy the app that same weekend.


After two endless nights of coding, we crossed the finish line. At 9:12pm on Sunday, we successfully deployed the app to the app store. As engineers and designers, our creative juices need to be regularly exercised. Throughout the weekend, we laughed, we pondered, we struggled, and we bonded. Investing in creative projects is a must in our studio.

— Austin Truong

I hope you enjoyed this story. Who are we? We make apps! If you have an app idea, we can help!