I used AI to code a personal trainer app in one weekend. I see why big apps fear the competition.

In a groundbreaking experience, I discovered the power of AI in app development during a coding workshop in Singapore. As a former fitness coach, I often found myself overwhelmed by juggling multiple apps to track my fitness journey. I used MyFitnessPal for dietary logging, an Apple Watch for workout duration, and various online videos for exercise guidance, which diminished my enjoyment at the gym. Inspired by the need for a streamlined solution, I embarked on a mission to create a personal trainer app that would consolidate all these functions. By the end of the weekend, I had developed a functional app called "TrainerPro" and realized why established fitness apps might feel threatened by such innovations. With the help of the AI tool Manus, I was allotted approximately 9,000 credits, equivalent to around $40 to $50, to bring my app to life. Manus, recently acquired by Meta but facing challenges due to regulatory issues, operates as a general-purpose AI that can produce code without being explicitly designed for coding tasks. The process was remarkably straightforward. I initiated the development with a simple English prompt, outlining the intended features and target audience of my app. The key was to define a clear scope, ensuring it wasn't too broad or too narrow. Within about 30 minutes, the AI generated my app without me needing to write a single line of code. TrainerPro featured a striking industrial design and was equipped with a comprehensive library of around 200 exercises, complete with GIF demonstrations and coaching cues. It could also create structured training programs over eight or twelve weeks, tailored to user goals and fitness levels, while considering elements like progressive overload and recovery periods. While I encountered minor bugs, such as some exercises failing to load, fixing them was a breeze. I simply communicated the issues to the AI, which resolved them promptly. The moment I opened my app in the gym, I felt a surge of pride knowing I had built it myself in just a few hours. I generated an eight-week training plan that outlined exactly what I was to lift each day, eliminating the need for constant app-switching or note-checking during workouts. Despite its functionality, the app did have limitations. I was unable to customize the exercise selection due to running out of credits, and I had forgotten to incorporate a meal tracker, making me rely on MyFitnessPal for nutrition. However, I realized that these obstacles were easily fixable with more time and resources. In a fitness landscape dominated by major players like Apple Fitness+, Strava, and MyFitnessPal, which have transformed into social platforms, I believe that traditional fitness apps are at risk. If someone without technical skills can craft a personalized fitness app in a weekend, it raises questions about the value of off-the-shelf solutions that lack adaptability. Although developing an app still requires investment in time and money, a one-time cost of $50 to $100 can be far more economical than recurring subscription fees. My app eliminated the need for multiple tools, combining workout logging, program generation, and training plans into one tailored solution. This new approach to app development, often referred to as vibe coding, allows for rapid, hyper-personalized solutions that cater to individual needs. It also opens avenues for entrepreneurship, as solving common problems with tailored apps can lead to successful side hustles. There's a unique satisfaction that comes from using something you created yourself. In a world where standing out is increasingly important, this customization offers tangible value. If you have your own experiences with vibe coding or app development, feel free to reach out to share your story.