Hello! I'm Srejon Khan 👋
Software Engineer and Founder. I build and break backends, firmware, and the things between them. Whatever I'm working on, the question I keep asking is: can I take one more step? Otherwise, being kind everywhere.
Software Engineer with 4+ years building high-throughput production systems across distributed services, real-time video infrastructure, embedded hardware, and developer tooling. Currently at a German HealthTech. Proven track record in microservices, observability, product engineering, and leadership.
Alongside my full-time Job, co-founded ArektaCompany to build ArektaCommute, a full-stack Commuter and Fleet Management Platform for the Bangladesh Education and Transport Sector. Building the full stack from ESP32 firmware through MQTT pipelines to web, mobile and desktop, with signed OTA updates and Platform Ops.
Final-year BSc in CSE (Data Science Major) at BAIUST, with a thesis on Computer Vision. Served as President of BAIUST Computer Club, coached 102 students, and organized two major CSE Fests with a notable 24-hour hackathon for 51 teams.
4x National Hackathon Champion, 10x Finalist (8 podiums), NASA Space Apps 2023 Global Nominee.
Skills
Projects
Full-stack RFID transport platform for university commuter management. Spans Next.js admin, Expo mobile, Tauri desktop CardDesk, and ESP32 firmware on a Hono + Bun monorepo backend.
Cryptographic NFC card scheme over MIFARE Classic 1K. Uses HMAC-SHA256 with the secret held by the desktop app and ESP32 firmware writing raw bytes blindly. Designed to make cloning and forgery detectable on every scan.
License system for Arekta's desktop software. HMAC-structured keys, server-side activation, hardware fingerprinting, 14-day offline grace period, and per-organization billing.
End-to-end live tracking pipeline. ESP32 + NEO-6M GPS + SIM800L modem firmware publishes positions over MQTT to a self-hosted EMQX broker, consumed by a Hono backend and broadcast over WebSocket to web and mobile clients. Signed OTA firmware updates.
Backend on Psyscreen, a LiveKit / WebRTC video conferencing platform for clinical psychological screening. Designed an internal envelope-encryption package (MEK/DEK with key rotation) replacing Hashicorp Vault, cutting service startup time by 70%. Led a small team on an internal monorepo starter kit that brought new-project setup from 3 hours to 15 minutes.
Edge-rendered student results portal on Cloudflare Workers. Load-tested at ~420 req/s with p95 = 79 ms, serving around 2.2K students. Replaced a slow lookup flow that previously took ~90 seconds.
Node.js + MongoDB ticketing system. Load-tested to sustain at least 10k emails/day at p95 = 150 ms, with auto-deduplication.
Privacy-compliant API and Postgres backend powering NICU vitals dashboards for clinicians. Built against ISO/IEC 27001 and BD Telemedicine 2020.
Single-player word-guessing mobile game in Unity/C#. Built with another developer; owned coding, testing, deployment, and the GitHub Actions CI/CD pipeline for same-day store releases.
Open-source REST client for Firebase. Still powering a mobile game with 5M+ downloads and ~30K MAU.
Cross-platform XR gameplay in Unity/C# sustaining 60 FPS. Architected the Firebase backend and shipped a one-click build-target switcher plus a Slack bot for closed-test artifact distribution.
Management software for the Medicine Department of Central Medical College, Comilla.
Pediatric drug-dosing assistant for medical students and new doctors. Calculates age- and weight-appropriate doses for routine pediatric medications.
Psychological horror prototype with action-thriller elements, set in fictional locations. Reached prototype stage.
Unofficial sequel to Project IGI 2. Built core gameplay components.
Honors & Awards
Schedule a Meeting
Want to discuss a project or just have a chat? Feel free to schedule a meeting with me.
Schedule on Calendly