Sajid Zakaria

Software Engineer•Competitive Programmer

Sylhet, Bangladesh
sajidzakaria1410@gmail.com+8801829856551

Professional Journey

My career path, key roles, and contributions in the tech industry.

Software Engineer

re:tune

Jan 2025 – Present
ReactExpo RNTypeScriptVapiStripelibSQL/TursoPostHogSentry
  • ✦Built a full-stack AI coaching platform with React/TypeScript; architected a backend and modular system design; engineered 30+ API endpoints and Stripe payment workflows; scaled ARR from near $0 to $19K+ in 2 months
  • ✦Reduced load times by 5x, improved uptime to 99.99%, and optimized DB operations by 40x (saving 2B row reads/mo)
  • ✦Integrated multimodal AI (LLMs, TTS, and STT using Claude, Gemini, OpenAI, and Deepgram) plus real-time voice via Vapi; optimized LLM usage with explicit caching and request tuning, reducing token usage and lowering API costs
  • ✦Orchestrated a live knowledge-ingestion and RAG retrieval pipeline (Storage → chunking/PII redaction → embeddings) using libSQL/Turso native vector search to power contextual coaching interactions
  • ✦Delivered an iOS mobile app with native Sign in with Apple, OAuth integration, and an in-app purchase system with server-side receipt verification, plus streamlined subscription management via App Store Server Notifications

Full-Stack Developer

OrderE

Sep 2024 – Oct 2024
ReactNext.jsMUISSGISROptimization
  • ✦Delivered V2 of e-commerce platform serving 500+ businesses, generating £6.1M in sales within 10 months
  • ✦Optimized performance with efficient algorithms and Next.js SSG/ISR, cutting page load times by 3x
  • ✦Built modern, responsive UIs with MUI and precise design translations for seamless user experience

Backend Developer

Bangladesh Competitive Programming Society

Jun 2022 – Jun 2024
PythonFastAPIDiscord.pyFirebaseSQLiteCaching
  • ✦Boosted community engagement 5x through personalized features and contest alerts
  • ✦Built and maintained 20+ API endpoints; cut API response times 3-4x with in-memory caching
  • ✦Deployed virtual currency system, systematized rewards, seasonal leagues, and real-time leaderboards

Technical Arsenal

Technologies and tools I use to bring ideas to life

Programming Languages

C/C++
Python
Java
TypeScript
Kotlin
JavaScript

Frameworks & Libraries

React
Next.js
Node.js
Django
FastAPI
Express.js
SvelteKit
TailwindCSS
MUI

Databases & Storage

MySQL
PostgreSQL
MongoDB
Firebase
SQLite
libSQL/Turso
SurrealDB

Cloud & DevOps

AWS
Azure
Docker
Vercel
Heroku
Fly.io

Problem Solving

Solved over 3500+ problems across various competitive programming platforms.

Featured Projects

Notable work demonstrating problem-solving and technical expertise

ST3-CP-Environment

40
PowerShellBatch ScriptsWindows
  • •Powerful programming environment for Windows with system-level automation
  • •PowerShell and Batch scripts for streamlined build and execution workflow
  • •Optimized for competitive programming with 40+ GitHub stars
View Source Code

LocateCrew

KotlinJetpack ComposeFirebaseAndroid
  • •Real-time crew tracking Android app with Kotlin & Jetpack Compose
  • •Leveraged Firebase for authentication, real-time database, and push notifications
  • •Enhanced team visibility and safety through live location sharing and messaging alerts
View Source Code

PixelPro

JavaJavaFX
  • •Desktop image editor using Java & JavaFX framework
  • •Features: brightness/contrast adjustment, crop/resize, blur effects, freehand drawing, text overlay
  • •Comprehensive implementation of event handling, graphics processing, and imaging APIs
View Source Code

SUST App

SvelteKitSurrealDBSkeleton UINodeJS
  • •Full-stack university management platform with SvelteKit & SurrealDB
  • •Faculty tools: student admissions, tuition records, course scheduling, attendance tracking
  • •Student portal: schedules, materials, performance tracking, registration system
View Source Code

Education

Academic foundation and formal qualifications

BSc. in Computer Science and Engineering

02/2020 - 10/2025

Shahjalal University of Science and Technology, Sylhet, Bangladesh

Higher Secondary School Certificate (Science)

2017 - 2019

Sylhet Government College

Awards & Recognition

Competitive programming achievements and academic honors

ICPC Asia West Finalist (2022)
Meta HackerCup Awardee (2018, 2023, 2024)
6th place, ICPC Regional (Dhaka Site), 2022
Champion, IUT Inter-University Programming Contest
4th, National Collegiate Programming Contest (NCPC)
4th, SUST Inter University Programming Contest
5th, CUET Inter University Programming Contest 2024
Top 50, Samsung R&D BD Code Contest 2024
Candidate Master on Codeforces (Top 6% globally)
6 stars on CodeChef (Top 1% globally)
9th place and divisional champion, BdOI 2019
Honorable Mention, National Physics Olympiad (2017)