You will get Javascript, React, React Native Marketplace web/mobile development
Top Rated
Project details
All in all, our spheres of expertise comprise multiple B2B & B2C marketplaces development responsively for desktop/mobile/tablet. Our focuses are retail, real estate, e-commerce, and fintech.
If you need to have an MVP for your Marketplace Web/Mobile app in a reasonable timely manner, with over 30+ projects successfully delivered, has a new offer for Marketplace businesses like yours. No need to pay the real cost of thousands of dollars (you'll get a rough estimation within' a few days after contact)
You will have full source code access, development, custom UI/UX and frontend design, back-end development, cloud hosting, test, launching the app, and best-fit support
We have done many Marketplace solutions so far. Here are the main features that will be included in your marketplace app:
• Onboarding for sellers
• Product management
• Order processing
• Promote listings
• Product search and display
• Communication between the roles
• Payment gateway integration and checkout flow
• Marketing features
• Monetization tools
• Map integration
• Others - designed to your specific needs
If you need to have an MVP for your Marketplace Web/Mobile app in a reasonable timely manner, with over 30+ projects successfully delivered, has a new offer for Marketplace businesses like yours. No need to pay the real cost of thousands of dollars (you'll get a rough estimation within' a few days after contact)
You will have full source code access, development, custom UI/UX and frontend design, back-end development, cloud hosting, test, launching the app, and best-fit support
We have done many Marketplace solutions so far. Here are the main features that will be included in your marketplace app:
• Onboarding for sellers
• Product management
• Order processing
• Promote listings
• Product search and display
• Communication between the roles
• Payment gateway integration and checkout flow
• Marketing features
• Monetization tools
• Map integration
• Others - designed to your specific needs
Programming Languages
JavaScript, Python, TypeScriptCoding Expertise
Cross Browser & Device Compatibility, Performance Optimization, DesignWhat's included
| Service Tiers |
Starter
$30,000
|
Standard
$40,000
|
Advanced
$50,000
|
|---|---|---|---|
| Delivery Time | 40 days | 55 days | 70 days |
Number of Revisions | 2 | 4 | 6 |
Number of Pages | 6 | 10 | 15 |
Design Customization | - | ||
Content Upload | - | - | |
Responsive Design | |||
Source Code |
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Anna D.
Dec 19, 2025
30 minute consultation
It was a great and very professional react native developer. I received detailed, practical recommendations and all the necessary documentation. Oleg is a true professional who clearly understands the topic and explains everything in a structured and helpful way. Highly recommended.
TM
Tobias Hahn M.
Dec 15, 2025
Birdie App
Amazing cooperation! Quick onboarding, GREAT project management from their side and overall really nice work.
AD
Alina D.
Oct 15, 2025
30 minute consultation
One of the best experiences I’ve had on Upwork!
AD
Alina D.
Oct 3, 2025
30 minute consultation
Great and very useful consultation!
EB
Ethan B.
Jul 7, 2025
Mobile App Development (React Native) for Social Community App
Available, lot of skills, good english and efficient and fast work. I recommend
About Oleg
AI Agent Builder | RAG Chatbot | AI Automation | Claude Architect
100%
Job Success
Cascais, Portugal - 9:45 pm local time
ABOUT ME
"You built an interesting project in very short time."
Saket Agarwal (Director of Engineering at Salesforce), CTO at evluv
10+ years, $600K+ earned on Upwork, 10,472+ hours billed. Top Rated Plus.
AI Agent Developer & AI Automation Developer.
What is running in production right now:
✅ Healify: AI health companion. Idea to production MVP in 6 months, ~$2M raised
✅ 300+ chats/day on a RAG support and lead-gen chatbot for a UK energy company
✅ 100K+ documents through RAG and OCR pipelines — invoices and bills of lading
for port logistics
✅ 6M+ users on RL Garage, cross-platform mobile app
✅ Production AI support agent on LangChain — intent classification, structured tool
calling, multi-turn regression evals in LangSmith, and a full compliance pass for a
regulated subscription business
✅ Self-hosted RAG over engineering drawings — SVG/DXF parsing, vector retrieval,
knowledge-graph layer for auditable answers with citations
✅ AI voice agent — inbound and outbound calls, lead qualification, appointment
booking, CRM-connected
✅ 10,000+ active users on a multi-tenant AI SaaS platform — Stripe billing, RBAC,
row-level security
✅ 25+ AI automation workflows (LanChain, Agents SDK) wiring AI agents into CRMs, Slack,
Telegram and WhatsApp
💬 3 of my last 3 paid consultations turned into ongoing projects
WHERE I DELIVER
AI Agent Developer, 25+ agent built: custom AI agents and agentic systems with LangChain, LangGraph
and MCP: tool calling, multi agent workflows, error handling, observability, evals,
production deployment.
AI Mobile Developer, 6M users, mobile AI apps and MVPs on React-Native, Next.js, Node.js,
Python FastAPI, Supabase and Stripe billing. Idea to production in 6-12 weeks.
AI Chatbot Developer, 300+ chats/day: RAG chatbots and AI assistants for customer support and lead
generation: WhatsApp, Telegram, web widgets, CRM integrations, human handoff.
MCP Developer, 5+ platform integrations: custom MCP servers connecting your APIs, databases and internal tools to Claude Desktop, ChatGPT and Cursor.
RAG Developer / LLM Developer — retrieval pipelines with pgvector and Pinecone:
embeddings, hybrid search, reranking, grounded answers with citations.
Generative AI Developer / Python AI Developer — OpenAI API and Anthropic Claude API
integrations inside existing products, without breaking what already works.
INDUSTRY IMPACT
AI SaaS Platform, AI Chatbot SaaS, RAG Knowledge Base — 10,000+ users, subscription
and usage-based billing, 99.9% uptime.
Document Automation, Document Intelligence, OCR AI — 2K+ documents processed,
90%+ manual work reduction in port logistics.
Ecommerce Chatbot, WhatsApp Automation, Customer Support AI — 300+ chats/day with
lead capture and human handoff.
Healthcare AI, Real Estate AI, Fintech MVP, EdTech AI — AI agents, RAG systems and
AI SaaS delivered across regulated and non-regulated domains.
Voice-to-Book AI App, Cross-Platform Mobile AI — 5.0 stars on App Store and
Google Play, shipped solo as an AI application developer.
HOW I BUILD
25+ agent builds: langchain, langgraph, mcp server, tool calling, function calling,
multi agent systems, agentic workflows, prompt engineering, rag pipeline,
retrieval augmented generation, langsmith evals.
15+ platforms: nextjs, react, typescript, nodejs, python fastapi, supabase, postgres,
pgvector, pinecone, stripe, aws, azure, vercel.
10+ bots: whatsapp chatbot, telegram bot, conversational ai, knowledge base chatbot,
customer support ai, openai api, anthropic claude api, gpt-5.
One full stack AI developer, no hand-offs: agent logic, RAG layer, backend,
frontend, deployment, and the evals that prove it still works next month.
🤝 HOW WE START
Need an AI developer who actually ships?
Shoot me a message or invitation and I'll send you a personalised loom on how I can help!
Steps for completing your project
After purchasing the project, send requirements so Oleg can start the project.
Delivery time starts when Oleg receives requirements from you.
Oleg works on your project following the steps below.
Revisions may occur after the delivery date.
Project Initiation
What will be done: - Defining the project scope, goals, and objectives - Establishing communication channels - Conducting initial feasibility studies and risk assessments - Developing a high-level project plan
Planning
It includes - Creating a detailed project plan, including timelines and milestones - Defining tasks, responsibilities, and resource requirements - Establishing a system for tracking progress and managing changes