Need a Flutter Developer for finalizing a Fitness App

Hi,

I’m Jeo. I have 8+ years of experience in full-cycle mobile and backend development, including Flutter, scalable APIs, AI integrations, and production releases.

I reviewed the FIT HELPER specification carefully. The core product is already built, and the real challenge here is production integration, infrastructure setup, feature completion, and stable release delivery. That is exactly the kind of work I handle.

First, I will stabilize and deploy the existing stack: Flutter client with NestJS backend, connected to PostgreSQL via Prisma ORM. Infrastructure will be containerized with Docker and prepared for production scaling.

Then I will replace all mock data with live APIs, configure authentication flows (Google, Apple, email verification), and validate the full JWT lifecycle.
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For AI features, I will optimize your existing OpenAI API integration for food analysis, recipe generation, and fridge-image recognition with structured prompt engineering and output validation for accuracy.

For the mascot system, I recommend integrating the 3D assets through Flutter-compatible rendering and building the state engine around streaks, workouts, and user progress so the character evolves dynamically.

Subscription logic will be implemented with trial flow and weekly billing, structured for future monetization upgrades.

Push notifications, onboarding mechanics, planner, hydration tracking, and all unfinished logic will be completed as production-ready modules.

Final phase will include full QA, App Store and Google Play release preparation, and launch support.

I can take ownership of the full cycle — from deployment to release — and work directly with your designer for implementation alignment.

Ready for a call to review the current codebase and define the final roadmap.

Hello! I am a Full Stack Flutter developer for iOS and Android. I work with cross-platform development and create full-cycle applications.

I have experience in both independent development and in commercial teams. I also work with backend integrations: REST API, authorization, data synchronization, working with the cart, favorites, push notifications, and other business logic.

I have implemented projects from development to production and release in stores.

I would be happy to collaborate.

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Hello! I am a Flutter developer for iOS and Android, ranked in the top 15 in the field of hybrid mobile development. I have experience in both independent app development from scratch to release and working in commercial companies. I have also published apps in the App Store and Google Play - from preparation to full release. Confirmations can be found in my reviews on freelance platforms.

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Good day, we are ready to take on the full cycle of refining a fitness application on Flutter, covering all requirements of the technical specification - we have 4 years of experience in IT and experience working with mobile applications, server logic, and integrations in our portfolio - we offer solutions for building a stable application architecture, connecting and optimizing the database, integrating ML models for processing and analyzing user data, as well as full support from development to release - we take responsibility for the quality, performance, and scalability of the product - we will be able to accurately determine the details of implementation, timelines, and cost after reviewing the technical specification - we work as a duo, which guarantees a comprehensive approach.

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Hello, we are a small team that has been developing turnkey cross-platform applications for over 4 years and are ready to take full responsibility for the architecture and functionality of your fitness project. We will build a logical structure for interaction with AI modules, ensure clean integration with the backend, and implement the entire list of requirements from the technical specifications without involving third-party specialists. Our experience of over 4 years allows us to guarantee a high product culture, technical cleanliness of the code, and full compliance with deadlines. Be sure to check our completed projects: freshagro.com.ua, farfieworldwide.com, rivnekolo.com.

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Good day, my colleague and I have been professionally engaged in technical design and the development of mobile solutions (iOS/Android) on Flutter for over 4 years, so we will help you complete the entire list of tasks from your technical specifications. We will implement a frontend audit of the current state of the application, set up complex business logic using ML models for personalizing workouts, and ensure the reliable operation of the database. Our experience of over 4 years is confirmed by successful cases of developing complex ecosystems that we have managed independently; familiarize yourself with our quality of execution: drkukharevich.rivne.ua, crave-agency.com.ua, jk-solution.com.ua.

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Hello, my partner (designer + full-stack) and I have been specializing in the development of high-load mobile applications on Flutter for over 4 years, so we professionally implement the full cycle of refinement for your fitness application. We will design the architecture in Figma to visualize complex interfaces, implement technically flawless database integration (Firebase/PostgreSQL), and develop ML/AI modules for analyzing physical activity. Our experience of over 4 years allows us to independently manage the project from design to publication in the Store, ensuring code stability and performance; take a look at our technical works: hyperfi.tech, espressolab.com.ua, hudi.com.ua.

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Hello!
I am an experienced Flutter and backend developer in the TOP-10, specializing in creating complex mobile applications "turnkey". I have reviewed your requirements and am ready to take full responsibility for the project.
My works and reviews:
• GitHub: https://github.com/KIS-IT-PRODUCTION
• Portfolio: Freelancehunt
• Reviews: Freelancehunt

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Hello. I read the technical specifications carefully — I have been primarily involved in production in recent years and have production references on similar services: I developed the backend for Qwqer (delivery/taxi, Latvia) and several other projects with real-time integration. I have always managed projects independently.

During the analysis of the specifications, several points immediately stood out to me as important:

— A realistic estimate should include an audit and refinement of the existing code. Checking what actually works vs where there are mocks/stubs, assessing the quality of the NestJS architecture, the state of Prisma migrations, and whether the Flutter screens are actually being built. Without this stage, all other estimates are speculation.

— The 3D character in Flutter is the riskiest block in terms of hours. A lot depends on the format of the source files from the designer (Rive / glTF / possibly Unity-as-library). This is a budget variance of x2, so it makes sense to discuss it in advance.

— The AI part in the specifications is described as "setting up prompts," but the Vision API for recognizing a refrigerator and the accuracy of nutritional information based on photos is normal prompt engineering with a test suite on standard dishes; I would allocate it as a separate stage.
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— The deadline of June 1 for one developer for the entire scope is objectively difficult. It makes sense to divide it into "must-haves for v1" and "v1.5" to release something live and stable by June 1.

— There are points that are not in the specifications but are important: Sentry/Crashlytics, analytics (at least Firebase Analytics), rate limiting on the backend, basic JWT security (rotation/blacklist), GDPR flow for account deletion (a requirement from Apple since 2022).

I work on an hourly rate starting from $25.

I am ready to discuss in more detail, go through the application live, and finalize the list and deadlines.

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Hello! I have reviewed the document and am ready to complete the project, I have experience, and I have time to take it on now.

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Hello, I have experience in developing applications from idea to publication. I also have similar experience with similar applications. Write to me privately. I will be happy to help you!

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Hello, I have developed dating applications on Flutter, implementing them for both iOS and Android, and I would be happy to work on and complete this task. I can also take on the backend as I am familiar with the stack. Regarding 3D, it is necessary to understand in which application the model was created in order to integrate it perfectly.

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Hello Roman,
Based on your requirements; what I Cover — All of It
Flutter / Dart (Client)
I work with go_router, flutter_secure_storage, image_picker, and http daily. I'll assemble the existing codebase locally in Phase 1, verify all screens render correctly, then systematically replace every mock with live API calls. Navigation tab order, auth flows (Apple ID, Google, Email+code), and all screens — tested on real iOS and Android devices before release.
Backend (NestJS + PostgreSQL + Prisma)
I'll deploy the existing NestJS/Fastify backend on a VPS with Docker, run Prisma migrations, configure PostgreSQL, set up HTTPS, and wire all .env keys including OpenAI, SMTP, Google OAuth, and Apple Sign In. The infrastructure foundation will be solid before any feature work begins.
AI Configuration (OpenAI GPT-4o-mini)
The integration is already written — my job is to craft and validate the prompts. I'll tune and test:

… Food analysis by text and photo (accurate KCAL/protein/fat/carbs)
Fridge photo → recipe suggestions with KBZHU and prep time
Daily nutrition tips and personalized recommendations
All AI responses will be validated against real test cases before release — no hallucinated calorie counts going to users.
3D Mascot Integration
I'll receive the 3D models and animations from your designer and integrate them into Flutter using the appropriate renderer. I'll implement the full state logic — progress-based appearance changes, streak milestone accessories (Day 7 / 14 / 30), section-specific poses (book for Mind, basket for Nutrition), and the daily motivational phrase system.
New Features (Phase 4)
Every item on your list:

Interactive body silhouette for training zone selection
Workout planner (weekly view)
Post-workout summary screen with animation
Onboarding tour mechanics with mascot slides
Payment by agreement after our call — as you specified. I'm ready for that conversation. Based on the scope, I'd estimate this falls in the 3,500 – 5,500 range for v1, but I'll confirm after we walk through the app together live.
I'd suggest we schedule a call this week — you open the app, walk me through each screen, and we lock down the final task list, budget, and a realistic milestone schedule together.

Good day!
I have reviewed the technical specifications, the project is clear, the technology stack is familiar, and I am ready to work.
What I see in the task:
Deploy the infrastructure, connect external services, implement new features (primarily the 3D mascot and AI functionality), and get the client working with the real API.
This is a reasonable scope for the deadline of June 1, provided that the source files are in working condition and there are no critical architectural debts.

My approach:
The first step is to obtain the archive, set everything up locally, and conduct an audit: what actually works, where there are placeholders, and where potential problems lie.
After that, I will schedule a call with specific questions about each screen, rather than assumptions.
… At the same time, I will connect to Figma and start synchronizing with the designer from the first day of work on the project!

What I would like to clarify:
The current state of the codebase — are there any TypeScript errors, debts in Prisma, dependency conflicts?
The format for delivering the 3D source files for the mascot (glTF / FBX / Lottie) and the readiness of the timeline for them.
The budget for OpenAI — this will affect the architecture for caching AI requests.
Priorities within stage 4, if we cannot complete everything by June.

I am ready to start immediately after the call.
Please let me know a convenient time — we will agree on the details and finalize the task list.

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Hello! I have reviewed the technical specifications. I am ready to take full responsibility for the project and bring it to release on both platforms.

My stack and experience allow me to meet all the stated requirements:

Flutter (iOS/Android): I write clean, maintainable code with a well-thought-out architecture.

ML/AI integration: I have experience in training and implementing AI functionality (including working with LLM and automating logic), which is critical for modern fitness applications.

Backend & DB: I design and integrate databases, ensuring synchronization and high performance.
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Independence: I manage projects "turnkey" — from setting up architecture to deployment. You will not need to look for separate specialists for different tasks.

Feel free to write, I would be happy to discuss the project details!

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