Transactional Correctness
Important state changes should happen atomically and consistently.
ARYAN RAJ / JAVA BACKEND ENGINEER
Building systems that stay correct under pressure.
Java Backend Engineer in Bangalore | Spring Boot & Microservices. I build reliable backend systems with PostgreSQL, with a focus on transactional correctness, concurrency, security and scalable API design.
TRANSACTIONS / CONCURRENCY / SECURITY / RELIABILITY
BACKEND ENGINEERING● FOCUSED
Java · Spring Boot · PostgreSQL
REST APIs / Security / Data consistency
- Transactions
- Concurrency
- Security
- Idempotency
01 / Engineering focus
Reliability is a design decision.
The interesting backend problems are often invisible when everything goes right. These are the areas I like to make explicit.
Concurrency
Race conditions, locking and concurrent requests deserve deliberate design.
Security
Authentication, authorization, JWT, RBAC and secure API design.
Database Consistency
Relational modeling, transactions and constraints that protect state.
Reliable APIs
Structured, validated and predictable REST APIs with safe failure handling.
02 / Technical stack flow
Tools in motion.
A practical path from language to framework, data, reliability and delivery.
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03
03 / Featured system
Double Ledger
A transaction-safe banking backend designed around double-entry accounting, secure APIs and concurrency control.
BANKING SYSTEM / JAVA + SPRING BOOT
Correctness, recorded twice.
Double Ledger models every transfer as a double-entry operation: a debit from one account, a credit to another, and a transaction record that keeps the whole operation accountable.
STACK
Java · Spring Boot · Spring Security · PostgreSQL · React · Docker · GitHub Actions · Maven
Double-entry ledger
Concurrent fund transfers
Pessimistic row-level locking
Deterministic account ordering
Deadlock prevention
Idempotency keys
JWT + refresh-token rotation
BCrypt password hashing
Role-based access control
Audit logging
JUnit / Mockito testing
Safe failure handling
TEST ACCESS
Authorized evaluation accounts. Customer registration and account opening still follow the bank onboarding workflow.
Passwd: Kumar@123Passwd: Gaurav@12303 / More work
Systems with a clear job.
HR Management System
IIT Gandhinagar x Odoo Hackathon 2025 Finalist. Spring Boot + Spring Security + JPA + PostgreSQL + JWT + RBAC.
ENGINEERING
Employee management / Attendance / Leave / Payroll / RBAC
STACK
Spring Boot · Spring Security · JPA · PostgreSQL · JWT · RBAC
Secure citizen crime reporting system
Spring Boot REST API with PostgreSQL, RBAC, AWS, and Google Maps integration.
ENGINEERING
Secure reporting / Role-based handling / Geo context
STACK
Spring Boot · REST API · PostgreSQL · RBAC · AWS · Google Maps
Real-Time Team Collaboration Platform
Built with Spring Boot, React TypeScript, Ably Realtime, Zegocloud, and PostgreSQL.
ENGINEERING
Real-time collaboration / Team workflows / Modern full-stack architecture
STACK
Spring Boot · React · TypeScript · Ably Realtime · Zegocloud · PostgreSQL
30+ hands-on Spring Boot projects
Hands-on Spring Boot learning repository organized by increasing difficulty.
ENGINEERING
30+ projects / Difficulty progression / Practical backend exercises
STACK
Java · Spring Boot · Maven · REST API · JPA
04 / Engineering thinking
What I look for in a system.
Transactions
Atomic operations and consistency.
Concurrency
Race conditions, locking and deadlock prevention.
Idempotency
Safe retries without duplicate operations.
Security
Authentication and authorization.
Database Design
Relational modeling and data consistency.
05 / Technical skills
The backend is the product.
A focused toolkit for building, testing and operating reliable services. React stays in its place: useful, but secondary.
BUILT FOR RELIABILITY
Languages
JavaJavaScriptTypeScriptSQL
Backend
Spring BootSpring MVCSpring SecuritySpring Data JPAHibernateREST API DesignJWT · OAuth2 · RBAC
Databases
PostgreSQLMySQLMongoDBRedis
Backend Engineering
MultithreadingConcurrency ControlTransactionsIdempotencyMicroservicesEvent-Driven DesignWebhooks · SSE
Testing & API
JUnitMockitoPostmanOpenAPI / Swagger
Cloud & DevOps
VercelRenderNeon PostgreSQLGitHub ActionsCI/CDDockerLinux
Build & Version Control
MavenGradleGitGitHub
Frontend
React
Familiar
KafkaDesign PatternsSOLID Principles
06 / Experience & education
Learning by shipping.
MAY 2024 - JUNE 2024
Java Development Intern
Coding Raja Technologies
- Developed Java CRUD modules including Library Management and School Management applications.
- Worked with structured application flows and database connectivity.
- Collaborated in a 5-member remote Agile/Scrum team.
- Participated in sprint planning, code reviews, pull requests and debugging.
2022 - 2026
B.Tech Artificial Intelligence & Machine Learning
Jai Narain College of Technology Bhopal (RGPV)
- First Division with Honours · CGPA: 7.71 / 10
- Relevant coursework: DSA, DBMS, Object-Oriented Design, Operating Systems, Computer Networks
07 / About
A practical interest in why systems fail.
I'm a Java Backend Developer focused on building reliable APIs and backend systems with Spring Boot, PostgreSQL and Spring Security. My interests are centered around transactional correctness, concurrency, database consistency and backend architecture. I enjoy understanding why systems fail under real-world conditions and designing mechanisms that keep them reliable.