WeiWei T.

I’m a Senior Full-Stack Engineer with 8+ years of experience building production-ready SaaS platforms, distributed backend systems, real-time communication products, AI voice agents, and e-commerce solutions. I help startups and established businesses turn complex ideas into scalable, reliable products—from architecture and backend services to responsive web applications, third-party integrations, deployment, monitoring, and ongoing production support. My strongest areas include: 🌐 Full-Stack SaaS Development • Java, Spring Boot, Spring Cloud, React, Next.js, TypeScript, Node.js, Python, and FastAPI • REST APIs, WebSockets, microservices, multi-tenant SaaS, admin dashboards, and internal tools • MySQL, PostgreSQL, Redis, Elasticsearch, Docker, AWS, and CI/CD 🎙️ AI Voice Agents & Real-Time Communication • AI phone agents, voice assistants, customer-service automation, and conversational workflows • Twilio, Telnyx, LiveKit, WebRTC, SIP, Asterisk, FreeSWITCH, and real-time messaging • STT, LLM, and TTS pipelines with interruption handling, DTMF, IVR navigation, call transfers, outbound calling, and low-latency audio • Integration with OpenAI, Claude, Gemini, Deepgram, ElevenLabs, and other AI providers 🤖 AI Agents, RAG & MCP • LLM-powered agents, RAG knowledge bases, workflow automation, and tool integration • Model Context Protocol (MCP) servers and tools for connecting AI agents to business systems • Agent memory, structured outputs, human approval workflows, evaluation, observability, and guardrails • n8n, Make, Zapier, CRM, email, calendar, database, and third-party API automation 🛍️ Shopify, Payments & E-Commerce • Shopify theme development, Liquid customization, responsive storefront implementation, and performance optimization • Shopify Admin API, Storefront API, webhooks, product and order integrations • Stripe, PayPal, Shopify Payments, subscriptions, refunds, reconciliation, and failure recovery • Secure webhook processing with signature verification, idempotency, retry handling, and audit logs ⚙️ Distributed Systems & Reliability • Kafka-based event-driven architecture and high-throughput messaging • Idempotency, retries, eventual consistency, distributed transactions, caching, and fault tolerance • Monitoring, logging, tracing, alerting, graceful degradation, and production incident debugging • OAuth2, OpenID Connect, Keycloak, RBAC, IAM, and multi-tenant security Relevant work includes real-time video meeting systems, online learning and e-commerce platforms, payment workflows, event-driven backend services, and AI-powered communication products. I can support the complete delivery lifecycle: • Architecture and technical planning • Frontend and backend implementation • AI, voice, payment, and third-party integrations • Production deployment and performance optimization • Debugging, modernization, and long-term maintenance If your project involves a full-stack SaaS product, AI voice agent, WebRTC platform, Shopify customization, payment integration, MCP tool, or complex backend system, I’d be happy to discuss the architecture and propose a practical delivery plan.