Senior Software Engineer

Job Description – Backend Java Developer (VAS & Billing Systems)

Job Title: Backend Java Developer Experience: 3–6 Years Employment Type: Full-Time Department: Engineering / Backend Development

About the Role

We are looking for an experienced Backend Java Developer with strong expertise in Java development, telecom Value Added Services (VAS), subscription management, and billing systems.

The candidate will be responsible for designing, developing, maintaining, and optimizing scalable backend applications handling high-volume subscription transactions, billing operations, payment processing, recurring renewals, retry mechanisms, and third-party integrations.

The ideal candidate should have strong technical knowledge of backend architecture, Java frameworks, database optimization, Redis, Apache Tomcat, Linux server administration, distributed systems, and production infrastructure management.

Experience working with telecom VAS platforms, operator integrations, and recurring billing systems will be a significant advantage.

Key Responsibilities1. Backend Development & Technical Architecture

• Design, develop, and maintain scalable backend applications using Java.
• Develop RESTful APIs and microservices using Spring Boot and Spring MVC.
• Design robust backend architecture for high-volume transaction processing.
• Write clean, reusable, maintainable, and efficient code.
• Implement multithreading, concurrency, asynchronous processing, and event-driven architecture.
• Participate in system design, technical architecture, and application scalability discussions.
• Identify performance bottlenecks and implement appropriate solutions.
• Follow coding standards, design patterns, and software development best practices.

2. VAS & Subscription Management

• Develop and maintain telecom Value Added Services (VAS) platforms.
• Implement complete subscription lifecycle workflows, including activation, deactivation, renewal, auto-renewal, expiry, and cancellation.
• Develop and manage subscription validity, grace period, and retry mechanisms.
• Integrate with telecom operators, aggregators, payment gateways, and third-party service providers.
• Understand telecom billing workflows, operator charging mechanisms, and subscription transaction flows.
• Handle high-volume subscription requests, charging requests, and operator callbacks.
• Ensure consistency between subscription status, transaction status, and billing records.

3. Billing & Payment Processing

• Develop and maintain billing engines and charging workflows for VAS platforms.
• Implement recurring billing, renewal processing, and automated retry mechanisms.
• Handle payment success, failure, timeout, and pending transaction scenarios.
• Implement idempotency mechanisms to prevent duplicate charging.
• Develop transaction reconciliation and audit mechanisms.
• Handle concurrent billing requests and ensure transaction integrity.
• Implement reliable billing processes with proper database transaction management.
• Troubleshoot discrepancies in charging, payment, and renewal operations.
• Optimize billing processes to ensure accurate and reliable revenue collection.

4. Database Management & SQL Optimization

• Strong knowledge of MySQL and/or PostgreSQL.
• Write complex SQL queries involving joins, subqueries, aggregations, and stored procedures.
• Design and optimize database schemas, indexes, and relationships.
• Analyze and optimize slow-running queries.
• Work with large transactional datasets and high-volume billing tables.
• Understand database transactions, locking, isolation levels, and deadlock handling.
• Knowledge of database partitioning, replication, and performance tuning.

5. Redis & Caching

• Hands-on experience with Redis for caching and high-performance data access.
• Implement caching strategies to reduce database load.
• Understand Redis data structures, TTL, expiration, and eviction policies.
• Use Redis for distributed locking, session management, and temporary transaction states.
• Understand cache invalidation and data consistency challenges.
• Implement rate limiting and other performance optimization mechanisms.

6. Messaging & Asynchronous Processing

• Experience with messaging systems such as Apache Kafka or RabbitMQ.
• Understand asynchronous processing and event-driven architecture.
• Implement reliable background jobs for subscription renewals, retries, and billing operations.
• Handle message acknowledgements, retries, dead-letter queues, and duplicate events.
• Ensure fault-tolerant and reliable message processing.

7. Apache Tomcat & Application Server Management

• Hands-on experience with Apache Tomcat application server.
• Deploy and manage Java applications using WAR files.
• Configure and manage Tomcat server instances.
• Understand Tomcat thread pools, request processing, and connection management.
• Perform JVM memory allocation and garbage collection tuning.
• Troubleshoot application deployment issues, server errors, and performance bottlenecks.
• Analyze application logs, server logs, and thread dumps.
• Optimize Tomcat configurations for high-traffic production applications.

8. Linux Administration & Production Server Management

• Strong hands-on experience working with Linux-based production servers such as Ubuntu, CentOS, or RHEL.
• Independently manage, monitor, and troubleshoot Linux servers through command-line interfaces.
• Manage Java applications, Tomcat, Redis, and other backend services in Linux environments.
• Monitor CPU, RAM, swap, disk utilization, and overall server performance.
• Perform application deployment, service management, and production troubleshooting.
• Analyze system and application logs to identify and resolve technical issues.
• Knowledge of Linux permissions, SSH, process management, networking, and scheduled jobs.
• Experience with Bash scripting and automation.
• Troubleshoot production incidents and perform root cause analysis.

9. Performance, Scalability & Reliability

• Develop applications capable of handling high transaction volumes.
• Optimize API response times and backend processing.
• Understand JVM performance tuning, garbage collection, and memory management.
• Identify and resolve database, Redis, Tomcat, and application-level bottlenecks.
• Implement logging, monitoring, alerting, and exception handling.
• Design fault-tolerant systems with appropriate recovery mechanisms.
• Ensure application availability and reliability in production environments.

10. AWS, Infrastructure & DevOps

• Working knowledge of AWS infrastructure, including EC2, RDS, CloudWatch, S3, and Load Balancers.
• Experience deploying and managing Java applications on cloud-based infrastructure.
• Familiarity with Docker and containerization.
• Knowledge of CI/CD pipelines and tools such as Jenkins or GitHub Actions.
• Experience with Git and version control workflows.
• Basic understanding of Nginx, reverse proxy, and load balancing.

Required Technical SkillsCategoryTechnologies / SkillsProgrammingCore Java, Java 8+, OOP, Collections, MultithreadingJava FrameworksSpring Boot, Spring MVC, Spring Data JPA, HibernateApplication ServerApache TomcatArchitectureMicroservices, REST APIs, Distributed Systems, System DesignDatabaseMySQL / PostgreSQL, Advanced SQL, Indexing, Query OptimizationCachingRedis, TTL, Distributed Locking, Cache ManagementMessagingApache Kafka / RabbitMQTelecomVAS, Subscription Management, Telecom BillingPaymentRecurring Billing, Charging, Payment Gateway IntegrationOperating SystemLinux Administration, Server Management, Bash ScriptingCloudAWS EC2, RDS, CloudWatch, S3DevOpsDocker, Jenkins, CI/CDDevelopment ToolsGit, Maven / Gradle, Postman, IntelliJ IDEAMonitoringApplication Logs, JVM Monitoring, Performance TuningPreferred Additional Skills

• Experience with telecom VAS platforms and operator integrations.
• Knowledge of SMS, USSD, IVR, CRBT, WAP, and digital subscription services.
• Understanding of SMPP protocol and telecom charging interfaces.
• Experience handling high-throughput APIs and concurrent transactions.
• Knowledge of database partitioning, replication, and large-scale data management.
• Experience with Elasticsearch or OpenSearch.
• Knowledge of distributed transaction management and eventual consistency.
• Experience designing billing reconciliation and transaction audit systems.
• Familiarity with monitoring tools such as Prometheus and Grafana.
• Experience with production incident management and root cause analysis.

Candidate Requirements

• Bachelor's degree in Computer Science, Information Technology, or a related field.
• 3–6 years of hands-on backend Java development experience.
• Strong understanding of Core Java, Spring Boot, and backend application architecture.
• Practical experience with MySQL/PostgreSQL, Redis, Apache Tomcat, and Linux administration.
• Experience working with production applications and troubleshooting critical issues.
• Good understanding of performance optimization, scalability, concurrency, and data consistency.
• Strong analytical and problem-solving abilities.
• Ability to independently handle development tasks and production-level technical challenges.

What We Are Looking For

We are specifically looking for a backend developer who understands more than just Java application development and CRUD API implementation.

The candidate should be capable of understanding the complete lifecycle of a VAS transaction, starting from subscription initiation to operator charging, billing confirmation, renewal scheduling, retry processing, callback handling, and final transaction reconciliation.

The candidate should be able to:

• Understand and contribute to overall technical architecture.
• Develop scalable and high-performance Java backend applications.
• Optimize complex SQL queries and database operations.
• Identify Redis, JVM, Tomcat, and application-level performance bottlenecks.
• Manage and troubleshoot production Linux servers independently.
• Handle duplicate transactions, concurrent charging, and failed callbacks.
• Troubleshoot production issues independently.
• Improve the reliability, scalability, and performance of billing systems.

Strong hands-on experience in telecom VAS platforms, subscription billing, recurring renewals, Linux server administration, and high-volume transaction processing will be a major advantage.

Pay: ₹584,000.00 - ₹700,000.00 per year

Benefits:

• Leave encashment
• Paid sick time
• Paid time off

Work Location: In person

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