Waleed S.

Next.js developer and full stack engineer with 6+ years of experience. I build web apps, SaaS products and startup MVPs with React and Next.js on Firebase or Supabase, handle Stripe integration and subscriptions, ship React Native Expo mobile apps, and add AI chatbots and OpenAI/Claude API features when your product needs them. Senior Software Engineer at a US AI EdTech company used across 20+ US schools. Top Rated Plus, 100% Job Success. If you need someone to own the frontend, backend, database, payments and integrations of your product, or to turn a prototype that works in a demo into something that holds up in production, that is exactly the work I do. FULL STACK DEVELOPMENT & SAAS - Next.js (App Router), React and TypeScript front ends; Node.js and Python / FastAPI back ends - Supabase and PostgreSQL: schema design, migrations, Row Level Security; Firebase / Firestore - Stripe integration: subscriptions, idempotent webhooks, upgrades and downgrades, trials, grace periods - Authentication, role-based access, admin dashboards, audited admin impersonation - API integrations: SSO and rostering, CRMs, OAuth APIs, webhooks - React Native / Expo mobile apps with in-app subscriptions - Production readiness: Sentry, OpenTelemetry, testing, CI and Vercel deployment AI ENGINEERING - LLM features with structured outputs: content generation and grading with Claude, Gemini and OpenAI, typed JSON with automatic repair, and multi-provider failover - RAG chatbots that stay grounded: pgvector, hybrid semantic + keyword search, per-tenant data isolation and citations - AI agents: LangChain / LangGraph agents with scoped tools and streaming responses; MCP connectors that let Claude act inside a business app - Quality and cost control: LLM-as-judge validation, prompt evaluations in CI with promptfoo, Langfuse tracing, per-call cost tracking SELECTED WORK - Subscription membership platform: Next.js, Supabase and Stripe, 46 RLS policies, two-way CRM sync, migration off a no-code platform - AI assessment platform: React, Firebase and Gemini structured output that generates assessments and executive reports - Admin operations platform with a Claude MCP connector: Next.js and Firebase, one-click connect with OAuth 2.1, so staff can ask Claude to create invoices, book meetings and send emails - My own privacy-first mobile app: Expo / React Native, Next.js and Supabase, with RevenueCat subscriptions - AI EdTech platform: multi-provider LLM generation and grading, gated by ~37 LLM-judge validators, in daily use by schools - AI student advisor: LangGraph agents and multi-tenant RAG on Python / FastAPI, Postgres + pgvector, Google Cloud HOW I WORK I start by finding what is fragile, write down a plan, and ship in small, tested milestones. I use AI coding tools like Claude Code every day, behind tests and review gates, so speed does not cost you quality. You get clear written updates and code your team can maintain after I hand it over. Send me your spec, prototype or broken feature and I will tell you what I would fix first.