Full-stack developer shipping production systems in React/TypeScript, Node.js/Fastify, PostgreSQL, MongoDB, and Docker — with a consistent focus on auth security, API contract design, and real-time data.
Six years coordinating complex operations under pressure built one rule: design for failure before you design for features — I bring the same precision regulators required in documentation to every codebase I touch.
Specialising in production LLM integrations — structured prompt pipelines, output validation, and AI-powered full-stack backends.
🌍 Stockholm, Sweden 📧 darunbjork@gmail.com 🎓 Fullstack Developer — Chas Academy (2025–2027) 💼 Open to Full-Stack, Frontend, and Backend roles 🔗 Portfolio: https://myportfolio-ui.netlify.app
| Project | Stack | Status |
|---|---|---|
| Research Assistant Platform | React · Fastify · Gemini · RAG · Pinecone | 🟡 In progress |
| Task Manager API | Bun · Fastify · PostgreSQL · Prisma | 🟡 In progress |
| Smart Home Frontend | React · TypeScript · Socket.io · Tailwind | 🟡 In progress |
🟢 Shipped · 🟡 In progress · 🔴 Planned
Node.js TypeScript MongoDB MQTT Socket.io JWT/RBAC Docker GitHub Actions Swagger
- Full IoT real-time loop — MQTT handles device commands; Socket.io fans state to all clients in <30 ms; closed-loop simulator validates the full device ↔ API ↔ client flow
- Production-hardened deploy — multi-stage Dockerfile, multi-platform image (linux/amd64 + linux/arm64), GitHub Actions CI, Swagger /api-docs, live on Render
- Zero cross-tenant leakage — RBAC + household-scoped middleware at the route layer; users physically cannot read or write another tenant's devices
React TypeScript Gemini API Bun Fastify PostgreSQL FastAPI Docker
- Structured prompt engineering — micro-step prompt pipelines + output validation cut off-format Gemini responses by ~85% vs unstructured prompting
- Resumable sessions — PostgreSQL-persisted quiz state with JWT accounts; users resume mid-session with zero data loss on reconnect
React TypeScript Tailwind Zustand Axios Node.js MongoDB Cloudinary JWT
- Hardened file upload pipeline — MIME type + size validation at middleware; invalid payloads blocked before reaching Cloudinary
- Production-scale frontend patterns — Zustand global auth state, Axios interceptor token refresh, abstracted API service layer
| Project | Description | Stack |
|---|---|---|
| DevQuiz API | Backend for AI quiz generation with Gemini, JWT auth, and Swagger docs | Bun · Fastify · MongoDB · Gemini |
| InsightAPI | Social platform backend — auth, posts, user relationships | Node.js · Express · MongoDB |
| Developer Portfolio | Responsive SPA with GSAP animations and Node.js contact backend | HTML · CSS · JavaScript · Node.js |
Frontend
Backend
AI & Prompt Engineering
Databases
DevOps & Tooling
APIs & Protocols
- 🔬 RAG architecture — retrieval pipelines, vector search, embedding strategies
- 🤖 AI agent design — tool-calling, multi-step reasoning, memory management
- ☁️ Cloud-native deployment — Kubernetes fundamentals, scaling strategies
- 🧪 Advanced backend testing — integration and contract testing patterns
1,622 contributions and counting — I build every day.
Fullstack Developer — Open Source Track · Chas Academy, Stockholm
Sep 2025 – Jun 2027 · Full-stack development, DevOps, cloud-native architecture
Full-Stack Web Development Certificate · CareerFoundry (Remote)
Jun 2023 – Aug 2024 · Frontend, backend, databases, deployment
Business Administration Diploma · Choman Technical Institute, Iraq
2011 – 2013 · Evaluated by UHR Sweden as equivalent to SeQF Level 5
⚡ Design for failure before you design for features.