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About
H
Haylemichael Tsega

About Me

Engineering systems that move money, data, and trust at scale.

I'm Haylemichael Tsega — a Senior Full-Stack Engineer with 5+ years of production experience architecting high-throughput distributed systems, real-time financial platforms, and cloud-native microservices. I studied Electrical and Computer Engineering (Computer Focus) at Addis Ababa Science and Technology University (AASTU), graduating with Great Distinction (GPA 3.81/4.0). My graduation project on Property Security and Warehouse Management was awarded by Inobizz and the Korean Embassy.

My stack centers on Node.js, TypeScript, React, and AWS serverless infrastructure. At EagleLion System Technology I architect backend systems serving 1M+ active users on a banking Super App — including an Automated Reconciliation System that cut settlement cycle time by 78% across 280+ post office agency nodes. Deep expertise in PCI-DSS-compliant payment systems, multi-tenant SaaS design, and Redis-backed performance optimization.

I design systems to survive production — observable, horizontally scalable, and maintainable by the next engineer who inherits the codebase.

“The best architecture is the one the team can understand, operate, and evolve — not the most technically impressive one on paper.”

Recognition

Awards & Achievements

🏆Award

Inobizz & Korean Embassy Prize

Awarded by Inobizz and the Korean Embassy for a graduation project in Property Security and Warehouse Management — recognized among the top engineering innovations at the ceremony.

🎓Academic

Great Distinction — AASTU

B.Sc. in Electrical and Computer Engineering (Computer Focus) from Addis Ababa Science and Technology University (AASTU) with a GPA of 3.81/4.0 — graduating with Great Distinction, Class of 2023.

🏦Industry Impact

Technical Team Lead at EagleLion

Leading the engineering squad architecting high-concurrency microservices for enterprise clients: Dashen Internet Banking, Edil Lottery, and Agency Banking platforms.

⚡Performance

40% API Latency Reduction

At AddisPay, profiled and optimized the critical payment path, cutting median response time by 40% through Redis caching, PostgreSQL query optimization, and connection pool tuning.

Technical Expertise

Skills & Technologies

Languages

TypeScriptJavaScript (ES2022+)SQLGoBash

Frontend

React.jsNext.jsRemixTailwind CSSWebSocket Client

Backend

Node.jsExpress.jsRESTful APIsGraphQLWebSocket ServersMicroservices

Cloud & Serverless

AWS LambdaAPI GatewayAmazon S3Amazon EC2Amazon RDSServerless Framework

Databases & Caching

PostgreSQLMySQLMongoDBRedis

DevOps & Tooling

DockerGit / GitHubCI/CD PipelinesLinux

FinTech Domain

Payment GatewaysAutomated ReconciliationAgency BankingInternet BankingPCI-DSS

Career

Work Experience

Feb 2025 – Present1M+ active users

Senior Full-Stack Engineer

EagleLion System Technology

  • ▸Architected a production-grade serverless backend on AWS Lambda and API Gateway for a banking Super App with 1M+ active users, sustaining sub-150ms P99 response times at 58,000+ concurrent requests per second.
  • ▸Deployed an Automated Reconciliation System across 280+ post office agency nodes, eliminating manual errors and reducing settlement cycle time by 78%.
  • ▸Integrated Redis caching, reducing PostgreSQL load by 72% and cutting average API response from 680ms to 140ms during peak banking hours.
Node.jsTypeScriptAWS LambdaRedisPostgreSQLExpress.jsReact
Jan 2024 – Present18+ enterprise clients

Full-Stack Engineer

Independent (Freelance)

  • ▸Built a real-time fleet management platform for 400+ active vehicles with WebSocket live map updates and event-driven GPS ingestion tracking 5,000+ daily trips.
  • ▸Architected a multi-tenant SaaS backend with row-level tenant isolation and RBAC, supporting 18+ enterprise clients with zero cross-tenant incidents.
  • ▸Secured all API endpoints with JWT, HMAC signing, and rate limiting — 100% clean penetration test results.
Node.jsTypeScriptReactNext.jsPostgreSQLWebSocketJWT
Jan 2024 – Feb 202535,000+ daily transactions

Full-Stack Engineer

Addispay Financial Technology

  • ▸Built transaction monitoring dashboards tracking 35,000+ daily transactions, reducing average review time by 40%.
  • ▸Secured payment gateway endpoints with JWT tokenization, HMAC request signing, and input sanitization, eliminating SQL injection and replay-attack vulnerabilities.
  • ▸Reduced frontend bundle size by 38%, improving Time-to-Interactive by 2.1 seconds.
ReactTypeScriptNode.jsExpress.jsPostgreSQLRedis
2022 – 202390+ students mentored

Code Coach & Technical Instructor

Code Jika NGO

  • ▸Mentored 90+ aspiring developers through structured curricula covering HTML, CSS, JavaScript, and full-stack project architecture, achieving an 85% course completion rate.
  • ▸Introduced industry-standard Git workflows, code review practices, and agile habits to accelerate graduates' time to first job placement.
HTML5CSS3JavaScriptGit