Fitblast
An AI fitness app that turns a goal, a fitness level and the time you actually have into a workout plan.
- Platform
- Mobile app for iOS and Android, one React Native codebase.
- Services
- Mobile app development, UI/UX design, design system in Figma.
- Stack
- React Native.
- Related services
- Public proof
- Fitblast on Behance
Mobile App
FitnessTech
Health & Wellness
SaaS
Fitblast is an AI-powered fitness app that helps people train effectively at home - without a gym or trainer
The app's artificial intelligence generates personalized workouts, visual exercise demonstrations, and motivational feedback.
Our goal is to make professional-level training accessible to everyone while keeping it engaging, dynamic, and effective.
.
Analyze user needs and define project scope.
Map interaction logic and the user journey
Structure content for early testing
Finalize visual system and interface graphics.
Build the functional app from final designs.
Research
Analyze user needs and define project scope.
User Flow
Map interaction logic and the user journey
Wireframes
Structure content for early testing
UI Design
Finalize visual system and interface graphics.
Development
Build the functional app from final designs.
What We Delivered
Bringing AI into fitness meant teaching technology to think like a coach - intelligent, balanced, truly human, and attentive.
Workout plans generated from goal, fitness level, time and energy
In-app AI Coach that explains what each exercise is for
Progression balanced across muscle groups by the algorithm, not the user
Built for people training at home, without a gym or a trainer
Building a Balanced AI System
Building a fully AI-driven fitness ecosystem wasn’t easy - we needed a reliable exercise database and an algorithm that could balance progression across all muscle groups.
Designing Human-Like Intelligence
We developed a smart AI model that analyzes user goals and creates natural, human-like workouts that feel curated by a real coach.
AI-Powered Personalization
Fitblast uses a combination of OpenAI’s language models and LangChain pipelines to generate tailored workout plans. Each plan adapts to the user’s fitness level, goals, available time, and energy.
Adjust workouts dynamically based on progress
Generate new exercises and sequences automatically
Provide personalized guidances via an in-app AI Coach
Technology Stack
The modern, robust, and scalable technology stack powering our AI-driven solution.
Frontend
Stack: React Native, Expo
Core Benefit: One codebase for the iOS and Android app people train with at home.
Backend
Stack: Python (FastAPI), PostgreSQL
Core Benefit: A modular microservice backend that carries the AI workloads and the exercise database.
AI & ML
Stack: OpenAI API, LangChain
Core Benefit: The models and pipelines that turn a goal, a fitness level and the time available into a plan.
Exercise matching
Stack: Vector search
Core Benefit: Dynamic exercise matching, so a plan rebuilt after a good week pulls movements that fit it.
Media
Stack: Automated video rendering pipeline
Core Benefit: The visual exercise demonstrations users watch, rendered from AI exercise data.
Animation
Stack: Lottie
Core Benefit: The micro-animations that celebrate a finished workout.
Design & Experience
The UI/UX design is inspired by gamified lifestyle aesthetics - energetic yet minimal.
We designed the interface to evoke motivation
For the user experience, we used clean typography, vivid progress colors, and Duolingo-style micro-animations that celebrate every achievement.
Outcome
Fitblast successfully transformed the concept of home workouts into a fully digital, transparent experience, where users clearly understand their progress, training logic, and personal goals.
The MVP integrated dynamic training generation, progress tracking, and motivational gamification - ready to scale globally.
Fitblast has been on the App Store since October 28, 2025.
Core Features
- Dynamic Training Generation
- Progress Tracking
- Motivational Gamification
Next Steps
- Nutrition Planning
- Voice Coaching
- Advanced Analytics Dashboards
Result
Facts you can check in the public store listings and on this page.
On the App Store since October 28, 2025
Also live on Google Play for Android
MVP live in both stores
One React Native codebase for both the iOS and Android apps
Who This Case Is For
Kultrix built Fitblast, an AI fitness app, from design to the App Store and Google Play with one team.
A non-technical founder with an idea for a health or fitness app
No in-house engineers: one team for design, development and QA
Apps for both stores: iOS on the App Store and Android on Google Play
A live MVP in both stores, like the Fitblast MVP
Project team
Management
Project leadership, controlling budget and timelines, setting technical direction.
Development
Build the product by writing code, developing server logic, and creating client-side applications.
Design & Quality
Designing the visual interface and user experience; conducting full quality checks.
How We Built It
Fitblast’s architecture was designed for scalability and AI evolution. Price a build like this against your own module list at kultrix.com/cost-calculator.
Modular microservice backend for AI workloads
Vector search for dynamic exercise matching
Live synchronization of AI recommendations & user activity.
Automated video rendering pipeline with AI exercise data
The Kultrix team brought our idea to life faster and better than imagined. They built a living product that understands and motivates people. The AI logic feels like real coaching magic!
Laurent D.
CEO of Fitblast
FAQ
Frequently Asked Questions
Fitblast is an AI-powered fitness app that helps people train effectively at home without a gym or trainer. It generates customized workouts, visual demonstrations, and motivational feedback.
Most people struggle to maintain consistent workout routines without professional guidance. Fitblast uses AI to create personalized training programs that adapt to each user's goals and progress.
The plan is generated from the user's goal, fitness level, available time and energy, and it is rebuilt as progress changes, so a busier week produces a shorter session rather than a skipped one. Progression across muscle groups is balanced by the algorithm. We describe the build here rather than outcomes we cannot source.
A smart AI analyzes user goals, fitness level, and progress to generate workouts that feel curated by a real coach. The algorithm balances progression across muscle groups for safe, effective training.
Dynamic training generation that adapts to your progress, detailed progress tracking with visual stats, and motivational gamification elements to keep you engaged.
React Native and Expo for the mobile app, Python (FastAPI) with PostgreSQL on the backend, OpenAI API and LangChain for AI features, and Lottie for smooth animations.
Nutrition planning to complement workout programs, voice coaching for hands-free guidance during exercises, and advanced analytics dashboards for deeper fitness insights.
The MVP was delivered in 3 months, and the app is live on Google Play and on the App Store, built for both iOS and Android from one React Native codebase: https://apps.apple.com/us/app/fitblast-app/id6754321009
Work of this kind - a mobile app with accounts and roles, AI plan generation and the media pipeline behind the exercise demos - sits in the AI-feature scenario of our calculator, 330-760 hours. The AI module on its own is 80-180 hours. Those are our ranges for work of that size today, not the figures of this project. Price your own module list at kultrix.com/cost-calculator.
In our calculator an AI feature in a live product is 6-14 weeks. A longer module list moves the weeks, and the week count for your own scope comes out of the first call.
From the same model that runs kultrix.com/cost-calculator. It is built from the actual hours of our own delivered projects. Module hours are added up, and the calculator shows the breakdown for your own module list.
Yes. Tell us which of these modules you actually need and we will price your list the same way: kultrix.com/contact. If you want the range before you talk to anyone, the calculator gives it in a minute: kultrix.com/cost-calculator.
Fitblast is a React Native app that we took through TestFlight and App Review to a live App Store listing. If your product is iPhone-first, read how we run iOS app development: the project path, the timeline, and when we write Swift instead of building cross-platform.
Services we used on this project
The same work, described service by service - scope, stack and how we estimate it.
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