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Open to Remote & Europe Roles

Senior Engineer.

Now Teaching.

I'm Denny Mathew — a Senior Java Backend Engineer with 12+ years building scalable systems across banking, insurance & healthcare. Now turning that into courses and free videos on DSA, System Design, Java & Spring Boot.

12+ years enterprise Java & Spring Boot
M.Sc. Computer Science — Scaler × Woolf University
41 free videos on YouTube · DSA, HLD, LLD, Java
Denny Mathew
Denny Mathew
Senior Java Backend Engineer
System X Engineering · YouTube
Open to Work
Java Spring Boot System Design HLD LLD DSA Microservices Azure REST APIs SQL Redis Kubernetes Distributed Systems Backend Engineering Java Spring Boot System Design HLD LLD DSA Microservices Azure REST APIs SQL Redis Kubernetes Distributed Systems Backend Engineering
12+
Years Engineering
41
Free YouTube Videos
M.Sc.
Computer Science
6
Courses Coming

About Me

Backend engineer.
Lifelong learner.

I'm a Senior Java Backend Engineer with over 12 years of production experience building enterprise systems across banking, insurance, and healthcare. My core stack: Java, Spring Boot, REST APIs, Microservices, Distributed Systems, SQL, Redis, and Azure.

I hold an M.Sc. in Computer Science from Scaler × Woolf University — covering system design, distributed systems, DB internals, and cloud architecture. I'm Microsoft Azure certified and completed an Advanced AI Engineering programme with IIT Roorkee.

On YouTube (System X Engineering), I publish free, no-nonsense videos on HLD, LLD, DSA, Java, and backend engineering. Courses are coming soon — structured, practical, built from real experience.

12+ Years backend
41 Free videos
6 Courses soon
Education
🎓
M.Sc. Computer Science Scaler × Woolf University Distributed Systems · System Design · Cloud
🏛️
B.Tech Computer Science CUSAT — Cochin University of Science & Technology
Certifications
AI Engineering SpecializationByteByteGo
Azure AI FundamentalsMicrosoft
Azure FundamentalsMicrosoft
Advanced AI EngineeringIIT Roorkee × Scaler

YouTube · System X Engineering

Free videos.
Watch right now.

View all 41 videos

Expertise

The tools I know
inside out.

Battle-tested skills from 12+ years of enterprise Java backend engineering across critical industries.

Backend Engineering

JavaSpring BootREST APIsMicroservicesAPI Design
🏗️

System Design

HLDLLDDistributed SystemsScalable Arch.
🗄️

Data & Integration

SQLRedisXML/JSONSOAP→REST
☁️

Cloud & DevOps

AzureDockerKubernetesCI/CDLinux
⌨️

Languages

Java (Primary)PythonSQLShell/Bash
🤝

Practices

Agile/ScrumProduction SupportMentoring

Learning Platform

Structured courses.
Coming soon.

12 years of engineering, distilled into structured courses. Follow on YouTube for launch updates.

01
Data Structures & Algorithms
Pattern-based DSA for FAANG-style interviews. From arrays to graphs to dynamic programming — zero to optimal.
ArraysTrees & GraphsDPRecursion
Coming Soon 🔔 Notify
02
🏛️
High-Level Design (HLD)
Design Twitter, Netflix, Uber. Real distributed systems — scaling, trade-offs, and architecture decisions.
ScalabilityLoad BalancingCAP Theorem
Coming Soon 🔔 Notify
03
🔩
Low-Level Design (LLD)
SOLID principles, design patterns and clean OOP. Master class-level design with real interview problems.
SOLIDDesign PatternsOOP
Coming Soon 🔔 Notify
04
Java & Spring Boot Masterclass
Core Java to production-ready Spring Boot APIs. Built from 12 years of hands-on backend engineering.
Core JavaSpring BootJPASecurity
Coming Soon 🔔 Notify
05
🗄️
SQL & Database Engineering
Fundamentals to advanced query optimisation, indexing, transactions, and database internals.
SQL CoreIndexingOptimisation
Coming Soon 🔔 Notify
06
🐍
Python for Backend Engineers
APIs, backend development, automation, and scripting. The second language every Java engineer should know.
Python CoreFastAPIAsync
Coming Soon 🔔 Notify
Actively Looking

Open to great
opportunities.

Looking for a Senior Java Backend Engineer with deep system design experience? I'm open to remote and Europe-based roles.

Senior Java Backend Backend Platform API Modernization Remote / Europe BFSI · Healthcare CET Timezone
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