KHALID

The Engineer behind the code.

I solve business problems through software. With over two years of experience in the industry, I've specialized in building distributed systems that are as scalable as they are maintainable.

My philosophy is simple: Code is for humans to read and machines to execute. I focus on clarity, performance, and usability in every line I write.

Khalid Hasan

Tech Stack

Languages

JavaScriptTypeScriptC++

Core Skills

System DesignOOPProblem Solving

Other

CommunicationAdaptabilityTeamworkProject Management

Technologies

Node.jsExpress.jsReact.jsNext.jsReduxDockerCI/CDMongoDBMongoosePostgreSQLMySQLPrismaFirebaseNextAuthJWTRedisBullMQAWS(EC2, Lambda, S3)

Doing Now

Building
  • • Portfolio Refinement
  • • SaaS Starter Kit
Learning
  • • Rust Programming
  • • Advanced Three.js
Reading
  • • Data-Intensive Apps
  • • Atomic Habits

Last Updated: April 2026

Full Timeline

Experience

Full-Stack Developer

SM Technology

Oct 2024 - Present

At SM Technology, I design and build scalable backend systems that power real-world web and mobile applications. From optimizing performance with smart caching and queues to integrating secure payments and managing AWS infrastructure, I focus on creating reliable, high-performance systems that scale smoothly under real traffic.

Architected and deployed scalable REST APIs using Node.js and NestJS serving web and mobile applications.

Designed Redis-based caching strategy reducing average API response.

Implemented BullMQ queue system processing asynchronous jobs (email, payments, notifications) improving system reliability under peak traffic.

Built real-time chat and notification system using WebSocket (Socket.io) supporting concurrent active users across platforms.

Engineered secure HLS video streaming infrastructure using AWS S3 and signed URLs preventing unauthorized content access

Integrated multi-provider payment gateway (Stripe, PayPal, Cryptocurrency) with webhook validation and automated subscription billing.

Managed AWS production infrastructure (EC2, Lambda, S3) ensuring scalability, monitoring, and deployment stability.

FullStack Developer Intern

Bangladeshi Software

Jul 2024 - Sep 2024

During my internship, I worked on building full-stack web applications using React, Next.js, and Node.js. I optimized APIs and database queries to improve performance and collaborated with the team to deliver production-ready features on time.

Developed full-stack web applications using React.js, Next.js, and Node.js.

Optimized API endpoints and database queries improving data retrieval speed.

Contributed to cross-functional development team, delivering production-ready features within tight deadlines.

Education

Bachelor of Science in Chemistry

National University ( Dinajpur Govt. College )

2018 - 2022