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Full-stack engineer with 5+ years shipping production systems with AI at the core, building multi-tenant LLM agent platforms and real-time voice experiences. I integrate and ship AI rather than train models—focused on agent orchestration, tenant isolation, and streaming lifecycle for revenue-generating products. I’ve built CRDT-based collaborative platforms, NestJS/React/TypeScript backends and APIs, and AI-ready developer workflows using tools like Cursor and Claude Code. I enjoy designing robust systems end-to-end: from typed integrations and offline-first sync to reliable WebRTC/WebSocket real-time architectures.…Full-stack engineer with 5+ years shipping production systems with AI at the core, building multi-tenant LLM agent platforms and real-time voice experiences. I integrate and ship AI rather than train models—focused on agent orchestration, tenant isolation, and streaming lifecycle for revenue-generating products. I’ve built CRDT-based collaborative platforms, NestJS/React/TypeScript backends and APIs, and AI-ready developer workflows using tools like Cursor and Claude Code. I enjoy designing robust systems end-to-end: from typed integrations and offline-first sync to reliable WebRTC/WebSocket real-time architectures.

Hassan Shahzad

Full Stack Developer, AI Engineer, Software Engineer, +2

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Full-stack engineer with 5+ years shipping production systems with AI at the core, building multi-tenant LLM agent platforms and real-time voice experiences. I integrate and ship AI rather than train models—focused on agent orchestration, tenant isolation, and streaming lifecycle for revenue-generating products. I’ve built CRDT-based collaborative platforms, NestJS/React/TypeScript backends and APIs, and AI-ready developer workflows using tools like Cursor and Claude Code. I enjoy designing robust systems end-to-end: from typed integrations and offline-first sync to reliable WebRTC/WebSocket real-time architectures.…Full-stack engineer with 5+ years shipping production systems with AI at the core, building multi-tenant LLM agent platforms and real-time voice experiences. I integrate and ship AI rather than train models—focused on agent orchestration, tenant isolation, and streaming lifecycle for revenue-generating products. I’ve built CRDT-based collaborative platforms, NestJS/React/TypeScript backends and APIs, and AI-ready developer workflows using tools like Cursor and Claude Code. I enjoy designing robust systems end-to-end: from typed integrations and offline-first sync to reliable WebRTC/WebSocket real-time architectures.

Available to hire

Full-stack engineer with 5+ years shipping production systems with AI at the core, building multi-tenant LLM agent platforms and real-time voice experiences. I integrate and ship AI rather than train models—focused on agent orchestration, tenant isolation, and streaming lifecycle for revenue-generating products.

I’ve built CRDT-based collaborative platforms, NestJS/React/TypeScript backends and APIs, and AI-ready developer workflows using tools like Cursor and Claude Code. I enjoy designing robust systems end-to-end: from typed integrations and offline-first sync to reliable WebRTC/WebSocket real-time architectures.

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Work Experience

Senior Software Engineer at Calandi GmbH

May 1, 2025 - May 1, 2026

Built AI-integrated collaborative platforms and complex financial systems using React, NestJS, and modern TypeScript ecosystems. Shipped an AI voice-to-text dictation feature using the OpenAI Realtime API and Whisper with WebRTC low-latency browser audio streaming, owning session lifecycle, reconnection, and error recovery while keeping the UI responsive. Engineered CRDT-based offline-first real-time collaboration for multi-user editing, including seamless sync. Developed typed end-to-end API integrations using OpenAPI-generated clients across the TanStack ecosystem (Router, Query, DB, Form), plus PWA offline support via service workers with strong Vitest and Playwright coverage. Also built and maintained NestJS APIs for fund operations (pricing, dividends, fees, shareholder management) and a React + Electron desktop app for fund operators, including bank transaction matching and automated workflows.

Senior Full-Stack Engineer at Calandi GmbH

May 1, 2025 - May 1, 2026

Built AI-integrated collaborative platforms and complex financial systems using React, NestJS, and modern TypeScript. Shipped AI voice-to-text dictation using the OpenAI Realtime API and Whisper, owning browser audio streaming via WebRTC with robust session lifecycle, reconnection, and error recovery while keeping UI responsive. Engineered conflict-free real-time collaboration using CRDT architecture with offline-first multi-user editing and seamless sync. Implemented typed end-to-end API integration using OpenAPI-generated clients across the TanStack ecosystem, plus PWA offline support via service workers, with strong test coverage using Vitest and Playwright.

AI Engineer (Full-Stack) at Hashlogics

January 1, 2025 - October 1, 2025

Built a multi-tenant AI conversational agent platform for healthcare clinics. Delivered a live, revenue-generating SaaS that follows up on stalled clinic lead threads in the clinic’s own tone of voice until the lead books or declines. Implemented per-clinic AI agent provisioning with clinic-scoped knowledge grounding and onboarding data, built the backend in Python/FastAPI (initially using LangChain then migrating orchestration to the OpenAI Agents API), and later moved parts to Supabase server functions. Shipped an embeddable JS widget for clinics and a lead capture funnel with context-aware follow-up messaging; designed for HIPAA-relevant/BAA-ready data handling.

Software Engineer at Software Alliance

March 1, 2024 - May 1, 2025

Worked on SaaS platforms and production applications across multiple domains. Led frontend development for a multi-tenant back-office SaaS for autonomous/cashier-less retail stores, including admin tools for vendors, suppliers, inventory, pricing, and campaigns, plus 3D inventory visualization using Three.js/React Three Fiber. Integrated Google Maps, Firebase Cloud Messaging, and supplier/accounting APIs; implemented multilingual (i18n) support for international rollout and mentored a junior developer. Also built NestJS APIs powering an iOS lifestyle app (prayer timings, GPS Qibla, tracking, push notifications, Stripe payments, and Qur’an content). Built full-stack Solana meme-coin trading automation including Raydium integration, WebSockets for live updates, cron scheduling, and a DexScreener scraper.

Associate Software Engineer at Techmania

January 1, 2022 - March 1, 2024

Built SaaS and service applications across healthcare, automation, and admin platforms. Developed a UK pharmacy operations SaaS (React + Node.js) and an online medical consultation backend (NestJS + TypeORM) with role-based auth, slot/appointment scheduling, delivery assignment, and driver/vehicle management, including Zoom API and payment gateway integration. Built social media automation and analytics across LinkedIn, Pinterest, Facebook, and Twitter with admin dashboards; designed reusable modular backend architecture for auth and core APIs; optimized MySQL performance.