I will build a custom ai web app with openai API


About this gig
Looking to launch a cutting-edge AI Web Application, Custom ChatGPT alternative, or AI SaaS platform? I build production-ready full-stack AI web applications using Next.js, Node.js, Python (FastAPI), and OpenAI / Claude APIs.
What I Can Build For You:
- Custom AI Web Applications & SaaS platforms
- ChatGPT-like conversational assistants with custom knowledge bases (RAG)
- Multi-modal AI applications (Text, Image, Audio processing)
- REST API & FastAPI backends connected to Next.js / React frontends
- Integration of OpenAI (GPT-4o), Anthropic Claude, Gemini, or open-source Hugging Face models
- Vector database setup (Pinecone, Supabase, Weaviate) for semantic search
- Secure User Auth (Clerk, NextAuth, Supabase) & Stripe Subscription Billing
Tech Stack I Use:
- Frontend: Next.js (App Router), React, TypeScript, Tailwind CSS
- Backend: Node.js/Express, Python (FastAPI/Flask)
- AI & DB: OpenAI API, LangChain, Pinecone, Supabase, PostgreSQL, MongoDB
Note: API usage costs (OpenAI, Pinecone, Vercel) are paid directly by the client under their own accounts. Please message me before placing an order so we can discuss your scope!
Get to know Thushanthan
Full Stack Web Developer , Software Developer , AI Integration Engineer
- FromSri Lanka
- Member sinceDec 2022
- Avg. response time1 hour
- Last delivery3 years
Languages
Tamil, Sinhala, English
My Portfolio
FAQ
Do you work with other AI APIs besides OpenAI, like Claude or Gemini?
Yes! I integrate Anthropic Claude, Google Gemini, Mistral, and open-source models via Hugging Face or Replicate, depending on your project needs.
Can you build the backend using Python and FastAPI instead of Node.js?
Absolutely. While Node.js is my preferred framework, I frequently build robust, scalable backends using Python (FastAPI or Flask) for heavy AI processing.
Will I own the source code and IP rights?
Yes, 100%. Upon completion and order approval, all custom source code and repository access are fully transferred to you.
How are third-party API costs (e.g., OpenAI, Stripe, Vercel hosting) handled?
You will set up your own API accounts. I will guide you step-by-step on how to generate API keys safely without sharing account credentials.