You will get AI features (Claude/OpenAI) integrated into your React or Next.js app
Top Rated
Top Rated
Project details
AI is the fastest-growing thing clients ask for - and the easiest to get wrong. A demo that works once is easy; an AI feature that behaves reliably for real users is engineering.
I integrate Claude and OpenAI APIs into web products as my daily work. What I ship is not a thin wrapper: real API integration with input validation, streaming, error fallbacks, rate-limit and cost controls, and maintainable prompts.
What I can add to your product:
• AI chat and assistants (streaming UI)
• RAG: answers grounded in YOUR data and documents
• Summarization, extraction, classification, generation
• Multi-step AI agents with tool calling
• Admin controls: editable prompts, usage limits, monitoring
Stack: React, Next.js, TypeScript, Node.js, Supabase/PostgreSQL, vector search, Claude & OpenAI APIs.
Why me: Senior React/Next.js developer, 10 years of experience, Top Rated on Upwork, $300K+ earned, 40+ products delivered - including production LLM features in live apps.
Tell me what you want your product to do with AI - I'll tell you honestly what will work, what it costs to run, and ship it production-ready.
I integrate Claude and OpenAI APIs into web products as my daily work. What I ship is not a thin wrapper: real API integration with input validation, streaming, error fallbacks, rate-limit and cost controls, and maintainable prompts.
What I can add to your product:
• AI chat and assistants (streaming UI)
• RAG: answers grounded in YOUR data and documents
• Summarization, extraction, classification, generation
• Multi-step AI agents with tool calling
• Admin controls: editable prompts, usage limits, monitoring
Stack: React, Next.js, TypeScript, Node.js, Supabase/PostgreSQL, vector search, Claude & OpenAI APIs.
Why me: Senior React/Next.js developer, 10 years of experience, Top Rated on Upwork, $300K+ earned, 40+ products delivered - including production LLM features in live apps.
Tell me what you want your product to do with AI - I'll tell you honestly what will work, what it costs to run, and ship it production-ready.
AI Algorithms
Large Language Model, Multimodal Large Language Model, Transformer ModelAI Applications
AI Chatbot, AI Content Creation, AI-Generated Code, Conversational AI, Natural Language GenerationAI Models
ChatGPT, DALL-E, GPT-4, WhisperWhat's included
| Service Tiers |
Starter
$1,500
|
Standard
$3,000
|
Advanced
$6,000
|
|---|---|---|---|
| Delivery Time | 7 days | 14 days | 21 days |
Number of Revisions | 1 | 1 | 2 |
AI Model Integration | |||
Batch Normalization | - | - | - |
Database Integration | - | ||
Detailed Code Comments | - | ||
Image Upscaling | - | - | - |
MLOps | - | - | - |
Model Deployment | |||
Model Documentation | - | - | - |
Model Monitoring | - | - | |
Model Testing & Optimization | - | - | - |
Model Tuning | - | - | - |
Natural Language Processing | - | - | - |
NLP Tokenization | - | - | - |
Pre-Training | - | - | - |
Prompt Engineering | |||
Setup File | - | - | - |
Source Code |
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ac
airesh c.
Jul 27, 2026
Frontend Developer — Audit & Fix Responsive Design Issues on Live Website
Excellent contractor. Delivered exactly what was needed with minimal back-and-forth, took feedback well, and kept me updated at every stage. Reliable and professional-highly recommend.
BF
Brendan F.
Mar 18, 2026
Customer Support Engineer
AA
Armend A.
Dec 9, 2024
Frontend Developer for DevTool project
JR
Jerome R.
Nov 15, 2024
CSS Expert Needed to make an existing page more responsive
It was a pleasure working with Anton, he understood well the task, managed to jump into an existing codebase and perform the task to our full satisfaction, has great communication and overall feels very professional. Will definitely work with him again when the need arises!
CP
Christoph P.
Nov 11, 2024
Frontend Developer with strong Next.js experience
Anton did a great job in our development team. You can rely on him to deliver high-quality work consistently and on time. His expertise in NextJS was evident as he seamlessly integrated into our team, quickly understanding our workflow and project requirements. Anton is not only technically skilled but also a proactive and reliable team player. He communicated effectively, kept us updated, and took the initiative to resolve any issues that arose. It was a pleasure working with him, and I would highly recommend him to anyone seeking a skilled and dependable frontend developer.
About Anton
Full Stack React/Next.js SaaS Expert | AI-Native, Supabase, Stripe
100%
Job Success
Warsaw, Poland - 1:00 am local time
I help startups and companies build and scale SaaS platforms, dashboards and AI-powered web apps — React, Next.js, Node.js, TypeScript, Supabase, Stripe. Top Rated, 6,875 hours on Upwork, 40+ products delivered.
Most of my work is complex SaaS: dashboards, internal tools, billing and subscriptions, authentication, multi-tenant architecture, admin panels, integrations, and performance-heavy applications handling large amounts of data and real business logic.
I also rescue and harden AI-generated codebases — apps started in Lovable, Replit or Cursor, or "vibe-coded", that need to become stable, secure, production-ready products. I know where that kind of code tends to break and how to fix it without a full rewrite.
I'm comfortable owning products end-to-end — from frontend architecture and product UX to backend APIs, database design, payments and third-party integrations. I've worked both on products built from scratch and on large existing codebases that needed to be fixed, scaled and cleaned up.
I build AI-native: I use Claude, Claude Code and modern AI tooling daily to move fast on implementation and exploration — while keeping architecture, security-sensitive logic and final code quality firmly under human review.
What i usually help with:
- SaaS platforms and startup products (0→1 and scaling)
- dashboards, admin panels and internal tools
- React / Next.js frontend architecture
- Node.js APIs and backend systems
- authentication, billing and Stripe integrations
- Supabase, PostgreSQL and database design
- AI integrations (Claude / OpenAI APIs, LLM product features)
- rescuing and hardening AI-generated or legacy codebases
- performance optimization, SEO and scaling
How i work:
- i think in systems, not isolated tasks
- i focus on maintainability and long-term scalability
- i communicate clearly and proactively, and work well async
- i can take ownership and make sound decisions from a spec, without heavy hand-holding
- i care about product quality, not just shipping features
Tech i use daily:
React, Next.js, TypeScript, Node.js, Vite, TanStack, Tailwind, Supabase, PostgreSQL, MongoDB, Stripe, Vercel, and modern AI tooling (Claude / OpenAI) depending on the project.
If you're building a SaaS product, launching an MVP, or need to turn a rough or AI-generated app into something production-ready — send me a message. I'll take an honest look at your setup and tell you how I'd approach it, what to improve, and what to expect.
Steps for completing your project
After purchasing the project, send requirements so Anton can start the project.
Delivery time starts when Anton receives requirements from you.
Anton works on your project following the steps below.
Revisions may occur after the delivery date.
Scope & design the AI feature
We agree on the exact feature, model (Claude/OpenAI), UX and success criteria before I write code.
Build & integrate
I implement the feature with streaming where useful, input validation, error fallbacks, rate-limit handling and cost controls.