Java Backend Engineer · Available for freelance

Mohaddis
Ahmad Khan

// Spring Boot · Kafka · Microservices · AWS · PostgreSQL

I build production-grade backend systems that handle real load — event-driven architectures, distributed microservices, and APIs that don't fall apart at scale. Based in New Delhi, India. Open to remote engagements worldwide.

4
years experience
3
live saas platforms
50+
rest apis shipped
10K+
events/sec (kafka)
mohaddis@dev ~ SparkE
git log --oneline -5
a3f2c1e feat: kafka consumer group rebalancing
b8d4e2a perf: redis cache ↓ latency by 45%
c9f1b3d fix: postgresql ltree query optimization
d2e8a7c feat: spring batch 500K record export
e5c3f9b chore: java 11 → 17 migration

docker ps
sparke-api Up 47 days :8080
kafka Up 47 days :9092
postgres Up 47 days :5432
redis Up 47 days :6379

_

Engineer who ships, not just codes

I'm a Java backend developer with around 4 years building real production systems — not demos, not side projects. I work on the kind of infrastructure where failures cost money and scale is non-negotiable.

My core stack is Spring Boot, Apache Kafka, PostgreSQL, Redis, and AWS. I've designed event-driven architectures, built Spring Batch pipelines for 500K+ records, led Java 11→17 migrations in production, and architected microservices that stay up when things go wrong.

I have a rare specialisation in EV charging infrastructure — including OCPP protocol compliance — which very few Java developers globally have in production. This gives me deep domain knowledge in energy, IoT, and fleet management systems.

Outside of Java, I'm actively learning Python and AI/ML engineering (LangChain, FastAPI, vector databases) to bridge backend expertise with the AI layer that every product now needs.

// tech_stack.json
Core Languages
Java 21 Java 17 Java 8 Python
Frameworks
Spring Boot Spring MVC Spring Security Spring Batch Hibernate
Messaging & Data
Apache Kafka PostgreSQL Redis Elasticsearch WebSockets
Cloud & DevOps
AWS S3 AWS SES Docker Maven Git
Testing & Quality
JUnit 5 Mockito SonarQube Swagger

Live production systems

Every project below is running in production with real users. Not tutorials. Not prototypes.

Live · Production
SparkE
EV Charging Network SaaS

End-to-end backend for an enterprise EV charging management platform. Real-time Kafka event pipeline, hierarchical PostgreSQL data modeling, Redis caching, and REST APIs serving enterprise fleet clients.

10K+
events/sec
30+
APIs built
45%
latency drop
Java 21 Spring Boot Kafka PostgreSQL Redis Elasticsearch AWS S3
Live · Production
ITS
Identity Management Platform

Event-driven batch processing system for enterprise identity data. Kafka consumer queues for high-concurrency ingestion, Spring Batch jobs generating ZIP/CSV archives for 500K+ identity records with sub-second latency.

500K+
records processed
70%
export time saved
<1s
processing latency
Java 17 Spring Boot Kafka Spring Batch AWS S3
Live · Production
OCTT
OCPP Compliance Testing Tool

Backend for an OCPP protocol compliance testing platform, validating EV charging station firmware against the international standard. WebSocket-based communication with Jetty, automated compliance test execution.

15+
bugs resolved
60%
failure rate drop
OCPP
1.6 + 2.0
Java 11 WebSockets Jetty OCPP 1.6/2.0
Completed
Veloce Energy
Power Grid Management System

REST API backend for distributed power grid management — customer, asset, and site lifecycle operations. Improved system stability and uptime through root cause analysis and targeted fixes across 10+ production issues.

50+
issues resolved
REST
API design
99.9%
target uptime
Java 8 Spring Boot PostgreSQL Docker

Where I've worked

2022 — Present
Java Backend Developer
Samin Tekmindz · Noida, India
  • Engineered 50+ high-performance REST APIs for enterprise EV charging and identity SaaS platforms, sustaining 99.9% uptime across 3 live production systems
  • Architected Kafka event pipelines processing 10,000+ concurrent session events with zero message loss and ~40% throughput improvement
  • Delivered Spring Batch jobs automating 500K+ record exports, reducing processing time by ~70%
  • Led Java 11 → 17 migration across 3 microservices, improving JVM memory efficiency by ~30%
  • Integrated Twilio SMS and AWS SES for real-time communication workflows serving 10,000+ users
  • Achieved 80%+ unit test coverage via JUnit 5/Mockito suites, reducing production defects by ~35%
2017
Master of Computer Applications (MCA)
Maulana Azad National Urdu University · Hyderabad
  • Specialised in computer science fundamentals, software engineering, and distributed systems
  • Graduated with strong foundation in algorithms, data structures, and object-oriented design

Let's build something.

Available for freelance projects, contract roles, and full-time opportunities. I respond within a few hours.