# S M Mahmudul Hasan

Human | Thinker | Engineer

## About
Building reliable smart systems, developer experiences and business automations

## Links
- GitHub: https://github.com/IamLizu
- LinkedIn: https://www.linkedin.com/in/sm-mahmudul-hasan/
- Twitter: https://x.com/IamLizu
- Blog: https://blog.smmahmudulhasan.com.bd

## Skills
- AI Engineering
- AI Application Development
- AI Agents
- Agentic Systems
- Retrieval-Augmented Generation (RAG)
- RAG Architecture
- LLM Integration
- LLM Orchestration
- AI Workflow Automation
- Context Engineering
- Prompt Engineering
- Model Evaluation
- MCP (Model Context Protocol)
- Software Architecture
- System Design
- Distributed Systems
- API Design
- Backend Architecture
- Multi-Tenant SaaS Architecture
- Database Design
- Cloud Infrastructure
- DevOps
- Application Security
- Secure Software Development
- Technical Leadership
- Engineering Management
- Product Development
- MVP Development
- SaaS Architecture
- Technical Strategy
- System Integration
- Performance Optimization
- Code Review
- Software Testing
- Developer Tooling
- Open Source Development

## Work Experience
### Technical Lead at Agency Handy (2025-04 - 2026-09)
Led the technical team and contributed across engineering, product, analytics, user experience, and customer support while building and operating a SaaS product.
- Led the technical team and worked closely with product and management
- Balanced technical decisions with customer and business priorities
- Built deeper expertise in SaaS operations, product analytics, and customer feedback

### Software Engineer at ZAAG SYSTEMS (2022-03 - 2024-12)
Built scalable systems and led delivery across identity, eCommerce, inventory, and multi-vendor products.
- Led development of a scalable queue-based ID generation system
- Built single and multi-location inventory and multi-vendor eCommerce systems
- Created reusable Node.js backend templates and fine-grained AWS IAM policies
- Managed project teams and delivered high-priority work

### Freelance Consultant at Wabble Web (2022-02 - 2022-02)
Built a client portal for monitoring CDN usage statistics.
- Created a portal for clients to log in and monitor CDN usage

### Freelance Consultant at Multipurpose Engineering & Industrial Automation (MEIA) (2022-01 - 2022-01)
Created a certificate management portal for issuing, managing, and verifying student certificates.
- Built certificate management workflows
- Enabled third parties to verify certificates issued to students

### Back-end Developer at Zonash (2020-12 - 2021-12)
Developed and operated backend services with Express, MongoDB, JWT authentication, automated workflows, and API documentation.
- Created APIs with Express and handled database operations with MongoDB
- Built API authentication with JWT and wrote unit and integration tests with Jest
- Automated workflows with GitHub Actions and managed Ubuntu servers
- Maintained API documentation, linting, and formatting

## Open Source
### Express.js - Member
Contributing to the Express.js ecosystem and community efforts.
- Community support
- Issue triage
- Documentation improvements

## Contact
Email: N/A
Location: Dhaka, Bangladesh