Kazi Efazul Karim

Full-time · Remote

Senior full-stack engineer building software for startups and founders — owning architecture and end-to-end delivery of full-stack web, mobile, and AI-assisted products for clients.

• Own end-to-end product delivery — architecture, APIs, data modeling, frontend, and mobile — from discovery to production.
• Architected a compliance-heavy litigation platform for a banking client spanning 124 branches and 5,000+ daily alerts, with maker-checker approval flows, branch-scoped permissions, and full audit trails.
• Led a multi-tenant education SaaS adopted by 6 schools and 3,000+ active users, documenting 250+ API endpoints for faster client handoff and QA.
• Improved reliability and performance through query optimization, caching, and containerized deployment across Docker, AWS, and VPS targets.
• Set engineering standards and mentored team members through code reviews, design documents, and pair programming.
• Automated document, report, and workflow generation with LLM/AI pipelines and background processing.

Contract · Remote

Senior full-stack engineer contracting with product teams on high-leverage web, mobile, and data initiatives in parallel with my full-time role at Fasten Teams.

• Built cross-platform mobile apps with React Native for iOS and Android, delivering native-feel UX and secure authentication.
• Designed REST APIs and backend services in Node.js and Python, with optimized database schemas and query performance.
• Shipped scalable web products in Next.js and TypeScript, from responsive UI to production-grade architecture.
• Implemented robust testing, code reviews, and clean architectural patterns that kept the codebase maintainable at team scale.
• Collaborated with design and product leads to ship intuitive, accessible interfaces with measurable user outcomes.

Contract · Remote

Provided end-to-end web and mobile development services for diverse clients across multiple industries. Built custom software solutions, e-commerce platforms, and business applications with focus on scalability and user experience.

• Developed and delivered full-stack web applications using React, Next.js, Node.js, and Python
• Built mobile applications using React Native for iOS and Android platforms
• Consulted with clients to define project requirements, technical architecture, and implementation strategies
• Implemented RESTful APIs and integrated third-party services (payment gateways, authentication, cloud services)
• Optimized application performance and implemented responsive designs for cross-device compatibility
• Managed database design and optimization using PostgreSQL and MongoDB
• Provided technical guidance and best practices recommendations to clients
• Handled project management, timelines, and client communications throughout the development lifecycle