Work History
Education
Overview
Generic

Mahendra Sai Sallagundla

Fort Collins,CO

Work History

Sr. Java Developer

Cigna Healthcare
01.2024 - Current
  • Designed, developed, and deployed Java 11, Spring Boot, Hibernate, and Spring Data JPA based microservices for claims processing, eligibility verification, and member management in enterprise healthcare systems.
  • Developed secure, reusable RESTful APIs for providers and members, and integrated legacy SOAP services using JAX-WS and Apache CXF to support existing core platforms.
  • Built Gateway API microservices in Spring Boot and Java 11, ensuring reliable, low-latency data exchange between AI-driven eligibility engines and downstream backend systems.
  • Implemented event-driven workflows using Kafka and RabbitMQ for real-time claims notifications, eligibility checks, and asynchronous communication across distributed services.
  • Deployed cloud-native applications on AWS, leveraging EC2, S3, RDS, Fargate, API Gateway, IAM, CloudWatch, and Secrets Manager to achieve scalability, resilience, and secure credential management.
  • Configured and used Flyway for schema versioning, automated database migrations, and data consistency across Oracle and MySQL instances in multiple environments.
  • Tuned JVM performance by analyzing garbage collection logs, optimizing heap memory, and improving multithreading and connection pooling, resulting in better throughput and reduced latency.
  • Optimized SQL queries, stored procedures, and indexes for large-scale transactional data, significantly reducing query response times for high-volume claims workloads.
  • Built and managed CI/CD pipelines with Jenkins, Maven, and Bitbucket, automating build, unit tests, integration tests, and deployments to AWS-based environments.
  • Containerized Spring Boot microservices using Docker and integrated them into AWS Fargate for consistent, repeatable deployments across dev, QA, UAT, and production.
  • Configured centralized logging and monitoring using Log4j/SLF4J, Splunk, and AWS CloudWatch, enabling proactive detection of issues, faster troubleshooting, and better observability.
  • Implemented unit and integration testing using JUnit and Mockito, and validated APIs using Postman, improving regression stability and supporting higher deployment frequency.
  • Built Angular 9+ dashboards consuming Spring Boot REST APIs, providing real-time views of claims and eligibility data for business stakeholders through POCs, demos, and internal tools.
  • Developed and deployed backend services following secure coding practices, including input validation, error handling, and encryption of sensitive data in line with HIPAA and healthcare security standards.
  • Secured services using OAuth2 and JWT-based authentication/authorization, integrating with identity providers such as Keycloak to implement role-based access control (RBAC).
  • Supported production releases, hotfix rollouts, and incident response, performing root cause analysis (RCA) and implementing permanent fixes to improve system stability and reduce repeat incidents.
  • Delivered technical documentation, including sequence diagrams, deployment guides, and release notes, to support knowledge sharing, onboarding, and audit/compliance activities.
  • Actively participated in Agile ceremonies (sprint planning, daily stand-ups, backlog refinement, sprint reviews, and retrospectives), providing estimates, status updates, and technical input for release planning.
  • Conducted peer code reviews, shared best practices, and mentored junior developers on Java, Spring Boot, and microservices design, improving overall team code quality and consistency.
  • Client: Cigna Healthcare | Remote

Sr. Java Developer

T-Mobile
05.2021 - 10.2023
  • Designed and developed Spring Boot microservices integrated with telecom billing, order management, and customer data platforms, enabling scalable OSS/BSS workflows.
  • Embedded SonarQube and Black Duck scans within Jenkins pipelines, applying quality gates and resolving findings to ensure early detection of code quality and security vulnerabilities across telecom applications.
  • Developed Spring Boot microservices in secure environments following OWASP guidelines, secure coding practices, and strong automated test coverage.
  • Gained hands-on exposure to telecom domain workflows including Wi-Fi calling, LTE/4G service activation flows, SIM lifecycle operations, and foundational understanding of 5G architecture and 3GPP-based provisioning standards used in OSS/BSS platforms.
  • Partnered with network engineering teams to validate provisioning APIs, investigate activation/billing defects, and analyze call-trace logs, improving onboarding accuracy and reducing activation failures across subscriber services.
  • Configured AWS-based clusters for containerized application deployments using Docker and Fargate, applying security policies and image scanning as part of the build and deployment process.
  • Automated code validation, dependency checks, and static analysis to provide full visibility into code health, vulnerabilities, and technical debt across services.
  • Collaborated closely with the security and DevOps teams to ensure all releases satisfied quality and security criteria prior to deployment into production environments.
  • Built secure REST APIs using Spring Security, OAuth2, and JWT to protect sensitive customer data across distributed systems and partner integrations.
  • Developed SOAP-to-REST adapters with Apache CXF to enable interoperability between modern microservices and legacy OSS/BSS systems.
  • Designed and implemented backend solutions using Core Java 11, Spring Boot, and microservices architecture, enabling seamless REST API-based integration for telecom billing platforms.
  • Developed and deployed AWS-native applications using ECS/Fargate, Lambda, API Gateway, and S3 to deliver scalable, secure, and fault-tolerant cloud operations.
  • Implemented event-driven communication using Kafka and RabbitMQ to handle asynchronous workflows such as call records, billing notifications, and order fulfillment.
  • Migrated legacy monolithic billing applications into containerized microservices using Docker and deployed them on AWS Fargate, improving scalability and deployment speed.
  • Designed and optimized schemas in Oracle, MongoDB, and PostgreSQL for customer and billing data management, ensuring data integrity and performance.
  • Used Flyway for schema migrations and version control across relational databases, supporting consistent deployments across environments.
  • Enhanced batch processing systems with Spring Batch and multithreading to process high-volume telecom billing data within strict SLAs.
  • Implemented caching strategies using Redis to reduce latency for frequent customer and billing lookups and improve overall API response times.
  • Configured CI/CD pipelines with Jenkins, Maven, Bitbucket, GitHub, and Nexus Repository Manager for automated builds, tests, and deployments.
  • Monitored applications with Splunk dashboards, SonarQube reports, and AWS CloudWatch alerts to track performance, errors, and security posture in real time.
  • Performed load and performance testing with JMeter to validate telecom microservices under high transaction volumes and peak traffic conditions.
  • Conducted unit and integration testing using JUnit and Mockito, and implemented BDD scenarios with Cucumber to improve test coverage and alignment with business requirements.
  • Automated API testing and functional regression testing using Postman as part of CI/CD validation for billing and activation services.
  • Produced Swagger/OpenAPI-based API documentation for internal teams and external vendors, improving integration speed and reducing onboarding time.
  • Configured Keycloak for role-based access control (RBAC) across microservices and API Gateway integrations, centralizing authentication and authorization.
  • Actively participated in Agile Scrum ceremonies including sprint planning, backlog refinement, reviews, and retrospectives, providing technical input and delivery estimates.
  • Performed peer code reviews, performance profiling, and JVM tuning to improve efficiency and reliability of billing and customer management services.
  • Supported production releases, hotfixes, incident resolution, and root cause analysis, ensuring minimal customer impact and faster recovery times.
  • Delivered system enhancements and security improvements aligned with telecom industry standards, GDPR, and data security regulations.
  • Client: T-Mobile | Remote

Java Developer

State of Colorado
12.2018 - 01.2021
  • Designed and developed e-commerce-style citizen service applications for licensing, payments, and service requests using Java 8, Spring Boot, Spring MVC, and Hibernate.
  • Built REST APIs for online payments, license renewals, appointment booking, and order tracking workflows.
  • Developed SOAP web services with JAX-WS for interoperability with legacy government and third-party platforms.
  • Implemented asynchronous messaging with Kafka and RabbitMQ for notifications, approvals, and transaction workflows.
  • Integrated secure payment gateways via REST and SOAP APIs, ensuring compliance with government security standards.
  • Created dynamic and responsive front-end components using Angular 9+, HTML5, and CSS3, integrated with Spring Boot REST APIs for license and payment management applications.
  • Delivered full-stack features combining Core Java 8/11, Spring Boot microservices, and AWS deployment, achieving faster API response times and improved user experience.
  • Designed and optimized schemas in Oracle and MySQL, improving query performance with indexing, triggers, and stored procedures.
  • Implemented NoSQL (MongoDB) for handling unstructured citizen service request data.
  • Enhanced application responsiveness with caching and pagination strategies for large service catalogs.
  • Developed Angular and Bootstrap front-end modules integrated with backend APIs for citizen-facing portals.
  • Applied HTML5, CSS3, SASS, LESS, and JavaScript to deliver responsive UI components aligned with accessibility standards.
  • Configured and deployed Docker containers for isolated environments and seamless integration into Jenkins pipelines.
  • Built and maintained CI/CD pipelines using Jenkins, Maven, and Nexus Repository Manager for automated builds and deployments.
  • Integrated Git and Bitbucket for version control, branching strategies, and collaborative development.
  • Conducted unit testing with JUnit and Mockito, and automated functional/regression testing using Selenium, Postman, and SOAP UI.
  • Developed BDD scenarios with Cucumber to ensure business rules were consistently validated.
  • Configured centralized logging and monitoring with Log4j, SLf4j, and Splunk, enabling proactive issue detection.
  • Produced UML diagrams, workflow documentation, sequence diagrams, and deployment guides for development and compliance audits.
  • Participated in Agile Scrum ceremonies (sprint planning, backlog grooming, stand-ups, sprint reviews, retrospectives) using JIRA and Confluence.
  • Coordinated batch processing with Autosys for scheduled license renewals and payment reconciliations.
  • Assisted QA and DevOps teams in performance tuning and security validation for citizen-facing applications.
  • Supported production deployments, hotfix releases, incident triage, and issue resolution, ensuring minimal downtime.
  • Ensured compliance with PCI-DSS standards for payment processing and secure handling of citizen data.
  • Client: State of Colorado | Denver, CO.

Java Developer

Target
03.2016 - 09.2018
  • Designed and developed backend services for retail order management, inventory tracking, and supply chain systems using Java 8, Spring Boot, Spring MVC, and Hibernate.
  • Built and exposed REST APIs for POS system integration and developed SOAP services using JAX-WS for legacy retail applications.
  • Developed multithreaded processes to handle high-volume retail orders, inventory updates, and payment reconciliation.
  • Designed and optimized relational schemas, complex queries, stored procedures, triggers, and indexing in MySQL and MongoDB to improve data performance.
  • Integrated third-party payment gateways via REST and SOAP APIs, ensuring PCI-DSS compliance for secure handling of credit card transactions.
  • Implemented caching and pagination strategies to optimize performance for product catalogs, shopping carts, and transaction history.
  • Migrated legacy SOAP services into RESTful microservices using Spring Boot adapters, reducing maintenance overhead.
  • Configured and deployed applications across JBoss, WebLogic, and WebSphere application servers for large-scale enterprise operations.
  • Enhanced API security using OAuth2, JWT, and SSL certificates to protect customer and transaction data.
  • Developed Angular and JavaScript dashboards for store managers to monitor orders, stock, and real-time store metrics.
  • Created responsive UIs using HTML5, CSS3, Bootstrap, and AJAX, integrated with backend APIs.
  • Deployed Docker containers for local development, test environments, and improved build consistency.
  • Built CI/CD pipelines with Jenkins, Maven, Ant, and Gradle, integrated with Git, Bitbucket, and GitLab for version control.
  • Enforced coding standards by integrating SonarQube quality gates and static code analysis tools like Fortify and Nexus IQ Server.
  • Monitored applications and logs using Splunk, Log4j, and SLf4j for issue resolution and proactive monitoring.
  • Performed unit and integration testing with JUnit, Mockito, and automated regression and UI tests using Selenium and Postman.
  • Conducted API testing with SOAP UI to validate SOAP-based retail services.
  • Created UML diagrams, design documents, release notes, and deployment guides for new and enhanced modules.
  • Participated in Agile ceremonies including sprint planning, backlog refinement, daily stand-ups, demos, and retrospectives.
  • Supported production systems by deploying hotfixes, performing root cause analysis, and improving system scalability during peak retail seasons.
  • Delivered enhancements that improved transaction throughput, order accuracy, and customer experience across e-commerce and in-store systems.
  • Collaborated with DevOps teams to configure deployments on Linux/Unix servers, ensuring high availability and fault tolerance.
  • Client: Target | Frisco, TX.

Java Developer

Morgan Stanley
12.2013 - 01.2016
  • Analyzed business requirements for trading and financial transaction platforms and contributed to design discussions for secure and scalable backend solutions.
  • Designed and developed backend modules using Java 8, J2EE, Spring MVC, Struts, Hibernate, and JDBC for processing high-volume financial transactions.
  • Built RESTful and SOAP web services to integrate with external trading platforms, payment gateways, and clearinghouse systems.
  • Designed and developed JSP- and Servlet-based web applications with XML/XSLT for dynamic content rendering and report generation.
  • Implemented EJB components and JavaBeans for transaction workflows requiring distributed transactions and reusability.
  • Integrated IBM MQ and JMS for secure and reliable messaging across multiple financial applications.
  • Applied JNDI for resource lookups and external service integrations.
  • Designed schemas and optimized queries across Oracle and MS SQL Server, implementing stored procedures, triggers, and indexing for performance improvements.
  • Performed SQL query tuning, partitioning, and PL/SQL optimization for batch-heavy systems.
  • Migrated legacy batch jobs to Spring Batch with error handling, scheduling, retry, and auditing mechanisms.
  • Configured deployments across Apache Tomcat, WebSphere, and WebLogic for enterprise-grade financial systems.
  • Enhanced security and authentication by applying OAuth2, SSL certificates, and role-based access controls for trading portals.
  • Conducted unit and integration testing using JUnit, Mockito, and Powermock, ensuring quality in mission-critical applications.
  • Automated API and functional testing using SOAP UI and Postman for internal and vendor-facing services.
  • Configured Log4j for centralized logging and integrated with Splunk for system monitoring and troubleshooting.
  • Developed UML diagrams, sequence diagrams, and architecture documentation for trading workflows.
  • Wrote Shell scripts, Python utilities, and Groovy scripts for automation, log parsing, and batch process validation.
  • Created CI/CD pipelines with Jenkins, SVN, and Ant, automating deployments and reducing release cycle times.
  • Participated in Agile Scrum ceremonies (sprint planning, backlog refinement, daily stand-ups, reviews, retrospectives).
  • Assisted in production support activities, including defect triaging, hotfix deployments, and post-trade settlement issues.
  • Collaborated with auditors and compliance teams to ensure SOX and PCI-DSS adherence, along with financial data integrity standards.
  • Provided knowledge transfer sessions, mentoring junior developers, and contributing to coding best practices in the team.
  • Supported multi-platform deployments across Linux/Unix, Windows, and MacOS environments.
  • Client: Morgan Stanley | Jersey City, NJ.

Java Developer

Exotel
07.2012 - 09.2013
  • Analyzed business requirements for cloud telephony and call management platforms, working with senior developers to design backend modules.
  • Developed Java/J2EE applications using JSP, Servlets, Struts, Hibernate, and JDBC for call routing, SMS gateways, and CRM workflows.
  • Built and exposed REST APIs for customer onboarding, call/SMS logging, and telecom billing integration.
  • Developed SOAP services for interoperability with legacy telecom providers and provisioning systems.
  • Designed JSP-based web interfaces with XML/JSON parsing for call flow configurations and reporting dashboards.
  • Implemented Hibernate ORM for persistence and optimized MySQL queries for subscriber data and call detail records (CDRs).
  • Automated log parsing, data extraction, and test data generation using Shell scripts and small Python utilities.
  • Supported multithreaded batch jobs to process high-volume SMS delivery reports and call activity records.
  • Configured Apache Tomcat servers for deployments, testing, and environment validation.
  • Performed unit and integration testing with JUnit and Mockito and supported QA with SOAP UI and Postman for API validation.
  • Configured Log4j for logging and collaborated with team members to resolve production issues.
  • Participated in Agile sprints (daily stand-ups, sprint planning, reviews) and delivered small feature sets.
  • Assisted in production deployments, defect resolution, and provided documentation for API workflows, deployment steps, and call flow diagrams.
  • Client: Exotel | Bangalore, India.

Education

Bachelor of Technology - Electronics and Communication Engineering

01-2012

Overview

14
14
years of professional experience

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Mahendra Sai Sallagundla