You will get Full backend development for apps
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Project details
Are you building a mobile or web application and need a reliable backend that can handle real users and real traffic? ⚙️
A strong backend is not just endpoints - it’s structured architecture, clean data models, and stable deployment pipelines.
Whether you’re launching an MVP or rebuilding an existing system, I deliver backend solutions built for stability and long-term scale.
Message me before placing an order to align on your product requirements and technical goals.
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A strong backend is not just endpoints - it’s structured architecture, clean data models, and stable deployment pipelines.
Whether you’re launching an MVP or rebuilding an existing system, I deliver backend solutions built for stability and long-term scale.
Message me before placing an order to align on your product requirements and technical goals.
Buzz: full backend development for apps, app backend development, backend development for mobile apps, backend development for web apps, full app backend development service, scalable app backend development, backend architecture development for apps, backend api development for apps, mobile app backend development expert, backend infrastructure for applications, backend system development for apps, backend engineering for applications, backend development service for apps, backend platform development for apps, backend development for saas apps, backend development consulting for apps, secure backend development for applications, production ready app backend development, backend development expert for apps
Programming Languages
JavaScript, Python, TypeScriptCoding Expertise
Localization, Performance Optimization, SecurityWhat's included
| Service Tiers |
Starter
$50
|
Standard
$100
|
Advanced
$200
|
|---|---|---|---|
| Delivery Time | 14 days | 30 days | 60 days |
Number of Revisions | 0 | 1 | 2 |
Number of Pages | 5 | 5 | 5 |
Design Customization | - | - | |
Content Upload | |||
Responsive Design | |||
Source Code | - |
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AR
Alexander R.
Mar 13, 2026
AI developer/team with React Native and Python experience for the Babycare/Wellness APP
Denys worked on our Mobile Application as a Full Stack developer using React Native and Python. He helped with mobile features, backend logic, and AI-related functionality. Communication was clear, tasks were delivered on time, and he focused on practical solutions that improved app stability and performance. It was a pleasure working with Denys.
About Denys
Full Stack Developer & Mobile App Development | React Native, Node.js
100%
Job Success
Odesa, Ukraine - 2:38 am local time
Most teams don't need another pair of hands writing tickets, they need a Full Stack Developer who can design the system, connect AI agents and LLM workflows to a real product without hallucinated features or runaway API costs, and explain every decision in plain terms. That's the gap I fill: architecture-level thinking with full stack and Mobile App Development execution.
As a Full Stack Developer, I work on the frontend and backend alike, building with React, Node.js, Express.js, and MongoDB as my core stack, backed by TypeScript and Python where they fit better. My Mobile App Development work extends that codebase into React Native apps for iOS and Android, so web and mobile products share logic instead of drifting apart. With hands-on tech lead experience, I don't just write code, I design the system and report progress clearly so the team always knows where the project stands.
Cloud & DevOps (AWS, Azure)
On the infrastructure side, I work as an AWS architect designing systems that stay reliable under real production load, not just in a demo — the same mindset I bring to web and Mobile App Development alike. This includes AWS Lambda for serverless workloads, database and storage setup, CI/CD pipelines, and AWS DevOps practices that keep deployments predictable, including mobile app builds and releases. I also bring working experience with Microsoft Azure.
AI Integration and API Integration
A growing part of my work as a Full Stack Developer moving into backend AI is AI Integration: connecting web and mobile products to the OpenAI API, Claude API, and LangChain workflows, building RAG pipelines, AI agents, and structured outputs that make AI features useful in production, not a demo. I handle API Integration end to end, including REST APIs, GraphQL, Stripe, Sendgrid, and Google APIs.
SaaS & Mobile App Development
As a Full Stack Developer I build multi-tenant platforms, subscription logic, admin dashboards, and customer-facing portals ready to grow with the business. My Mobile App Development brings the same architecture thinking to React Native apps: shared business logic, clean state management, and a mobile experience that matches the quality of the web product rather than trailing behind it.
Recent work
For a SaaS platform migrating from a single-tenant setup, I worked as Full Stack Developer restructuring the database schema and access layer for multi-tenancy without downtime.
For a startup launching alongside their web app, I handled Mobile App Development for a React Native app on iOS and Android sharing the same backend and business logic as the web product, cutting duplicate work.
For a product team adding AI features to an existing tool, I worked on AI Integration connecting their app to the OpenAI API through a RAG pipeline, keeping token costs predictable as usage scaled.
What I build
SaaS platforms and multi-tenant web applications, built by a Full Stack Developer who owns both ends of the stack. React Native mobile apps for iOS and Android, through Mobile App Development that shares logic with the web codebase. AI-powered features and LLM integrations added through hands-on AI Integration work. REST and GraphQL APIs connecting frontend, backend, mobile, and third-party services. Cloud infrastructure and deployment pipelines on AWS and Azure.
How I work
I'm a proactive, communicative Full Stack Developer with strong English, whether the work is backend architecture or Mobile App Development. I flag risks early, keep documentation current, and give honest, regular updates instead of silence between milestones. I treat every project the way I'd want my own business built: clear scope, clean code, a system the team can maintain after handoff.
What I don't take on: SaaS marketing, SaaS sales, WordPress-only builds, or Shopify-only integrations. If your project needs real backend logic or serious Mobile App Development beyond a template, that's where a Full Stack Developer like me comes in.
Clients typically bring me in when they
Need to launch a SaaS MVP and get it into paying customers' hands quickly. Have a platform that's outgrown its architecture and needs a Full Stack Developer to restructure it. Want Mobile App Development that shares logic with their existing web product instead of a separate rebuild. Want to add AI Integration without breaking what already works. Are looking for one Full Stack Developer who covers both web and Mobile App Development.
If you need a Full Stack Developer, Mobile App Development, a React Native developer, or an AWS architect for a SaaS platform with AI Integration built in, let's talk!
Steps for completing your project
After purchasing the project, send requirements so Denys can start the project.
Delivery time starts when Denys receives requirements from you.
Denys works on your project following the steps below.
Revisions may occur after the delivery date.
Discovery & Requirements Review
Client shares project details, goals, scope, and any existing materials. I review everything and align on expectations, timeline, and deliverables.
Review & Revisions
Client reviews the work. I apply agreed revisions and fine-tune the final output.