Full-Stack AI Integration Developer Needed for SaaS Platform (Next.js + OpenAI + LangChain)

We are a SaaS startup building an AI-powered content intelligence platform that helps marketing teams generate, analyze, and optimize content using OpenAI GPT-4 and Claude API. The core product is a web-based dashboard where users can input their brand details, connect their content sources, and receive AI-generated content briefs, SEO suggestions, and performance insights. We have the product design ready in Figma and a partial backend setup. We need an experienced Full-Stack AI Integration Developer to take ownership of the AI layer and frontend implementation end to end. What You Will Build: AI Content Generation Module: Integrate OpenAI GPT-4 and Claude API into our Next.js application. Users will input a topic, tone, and target audience and receive structured AI-generated content briefs, outlines, and first drafts. You will handle prompt engineering, response streaming using Vercel AI SDK, and structured output parsing. LangChain Agent for Content Analysis: Build a LangChain-powered agent that analyzes existing content URLs, extracts key themes, identifies content gaps, and returns structured JSON recommendations. The agent needs to handle multi-step reasoning, tool calls, and error handling gracefully. SaaS Dashboard Frontend: Build the complete Next.js frontend including user authentication via Clerk, multi-step onboarding flow, subscription management with Stripe, and the main dashboard with content project management, AI generation interface, and usage tracking. All UI must be built with Tailwind CSS and Shadcn/UI components, pixel-perfect from Figma designs. API and Backend: Develop Node.js API routes within Next.js for all AI operations, user data management, and third-party integrations. Connect to Supabase PostgreSQL for data storage with proper row-level security policies. Implement rate limiting, token usage tracking per user, and cost management logic. AI Response Streaming: Implement real-time token streaming for all AI generation features so users see responses appearing word by word, not waiting for full completion. Prompt Engineering: Write, test, and optimize system prompts for all AI features. Prompts must produce consistent, structured outputs. You will document each prompt with its purpose, parameters, and expected output format. Technical Requirements: Next.js 14+ with App Router, TypeScript throughout the entire codebase, Supabase for database and authentication fallback, Clerk for primary authentication and user management, Stripe for subscription billing with webhook handling, OpenAI API and Anthropic Claude API integration, LangChain for agent workflows, Vercel AI SDK for streaming, Tailwind CSS and Shadcn/UI for all components, Vercel for deployment. Deliverables: Complete Next.js codebase pushed to GitHub with clean commit history, all AI modules integrated and tested with sample inputs and outputs, Stripe subscription flow working end to end including webhooks, Supabase schema with migrations and RLS policies, documentation for all AI prompts and agent workflows, deployment on Vercel with environment variables configured, and a 30-minute handoff call walking through the codebase. Who We Are Looking For: You have shipped at least 2 to 3 SaaS products using Next.js in production. You have hands-on experience integrating OpenAI API and have worked with LangChain or Vercel AI SDK. You understand prompt engineering and can write prompts that produce reliable structured outputs. You are comfortable owning both frontend and backend and do not need a separate team. You communicate proactively and flag issues before they become blockers. Pakistani and international developers both welcome to apply. To Apply: Share 2 to 3 relevant projects you have built with Next.js and AI integration. Include a brief explanation of how you would structure the LangChain agent for content analysis. Tell us your estimated timeline for a project of this scope. Include your hourly rate or fixed price proposal.