Senior Full-Stack Engineer (Java/Scala/Python)

Sasikala Vasantha

PH: 925-***-**** ******************@*****.*** linkedin.com/in/sasikala-vasantha55/ Cupertino, CA

Professional Summary

Full Stack Engineer with around 6 years of experience designing and operating large-scale distributed systems and privacy-focused platforms. Strong expertise in Java, Scala, and Python, building highly available microservices using Spring Boot, Kafka, REST, and GraphQL, deployed on Kubernetes and AWS. Experienced in designing scalable React and TypeScript front-end applications that integrate seamlessly with distributed backend services. Skilled in control-plane style service design, event-driven architecture, and JVM performance optimization. Hands-on experience integrating AI/ML and LLM-powered capabilities into production systems for analytics, personalization, and intelligent search. Proven ability to modernize Java platforms, deploy cloud-native services on AWS, and operate production systems using CI/CD, Docker, Kubernetes, and Terraform, with a strong focus on reliability, performance, and user trust.

Work Experience

Full Stack Developer Apple, United States Jul 2023 - Present

Designed large-scale, partner-facing web applications using React, TypeScript, HTML5, and CSS3, establishing front-end architecture patterns, optimizing state management and rendering performance, and integrating REST APIs to handle complex workflows and high-volume datasets.

Improved UI performance and accessibility across complex user flows, built reusable React components and shared utilities, and implemented end-to-end API integration using Node.js, validating functionality through unit and integration testing with Jest and Playwright.

Led phased upgrades of a shared Apple Ads backend library from Java 11 to 17 to 21, refactoring DB-backed JSON outputs into strongly typed domain models and ensuring backward compatibility across Spring Boot distributed services.

Implemented backend microservices in Spring Boot and Node.js to process high-volume user events, integrating Kafka producers/consumers and persisting data in MySQL, MongoDB and DynamoDB, exposing services via gRPC and GraphQL for low-latency integrations across downstream systems.

Engineered secure APIs using OAuth 2.0 and JWT, delivering REST and GraphQL endpoints role-based access control, and service-to-service authentication across Spring Boot APIs and Kafka-driven workflows to protect sensitive user profile data in a high-throughput Apple Ads distributed system.

Built real-time user profile ingestion pipelines where Kafka-driven Scala consumers process opt-in/opt-out and profile updates, validating events and propagating changes across Hive, HBase, and Cassandra for near-real-time availability across segment consumer and segment server workflows.

Designed large-scale, privacy-first ad prediction systems (CTR/CVR) using Python and deep learning, building end-to-end ML pipelines for training, experimentation, and online serving, and applying exploitation strategies to improve ad quality, trust, and advertiser performance across Apple Services.

Implemented CI/CD pipelines using GitHub and Rio to automate build and scan workflows, triggering Apache Airflow DAGs for orchestration, and instrumenting services with Datadog metrics, tracing, and alerts to detect latency, ingestion failures, and data inconsistencies in production.

Extended distributed backend services onto AWS by deploying API workloads on Lambda, backend processing on EC2, and event data to S3, managing secrets with KMS and enforcing least-privilege IAM access for production systems.

Provisioned large-scale Kubernetes clusters using Terraform for infrastructure automation, Helm charts for application deployments, containerizing services with Docker, enabling consistent service rollout, environment parity, and controlled versioned deployments across multiple environments.

Software Developer IBM, India Jun 2019 - Aug 2021

Designed Angular SPA UI components using JavaScript/HTML/CSS and integrated Java/Python backend services for request processing, permission enforcement, and Oracle SQL data access across enterprise workflows and worked on SaaS applications across multiple environments.

Supported Java web services and client applications by managing Java/security certificates, enabling Java Web Start access, and resolving Microsoft Edge/Google Chrome compatibility issues.

Developed Spring Boot backend services for SPA workflows, exposed REST APIs and implemented database-driven business rules, validations, and request lifecycle handling.

Led operations for Oracle Database 19c and Oracle E-Business Suite R12.2, including 12c to 19c upgrades, instance cloning, user/responsibility administration, and production/non-production support.

Managed release deployments across 10+ Oracle EBS environments (Sandbox/Dev/QA/Preprod/Prod) and coordinated application and database script migrations using GitLab, WinSCP, and Linux.

Executed production and non-production deployments using IBM UrbanCode, provided on-call support and monitored application and database health via Splunk, OEM 13c, and Oracle RUEI.

Migrated Java full-stack applications from on-prem Oracle to AWS by updating Spring Boot configurations, validated Oracle SQL queries and verified data consistency, deployed services on EC2, and used S3 for migration artifacts and cutover verification.

Built and deployed Java SOAP services over HTTP on AWS, configured Oracle connectivity and validated end-to-end request/response processing for enterprise integrations.

Automated CI/CD workflows with Jenkins, Docker image build/tag pipelines, and provisioned AWS infrastructure using Terraform with environment-specific configuration and credential management.

Academic Projects

Big Data Analytics with Machine Learning for Healthcare and Financial Forecasting Aug 2022 - Dec 2022

Built a machine learning pipeline that combined genomics data, sensor readings, and patient records to flag early health risks, so clinicians could prioritize high-risk patients and support more personalized treatment suggestions.

Cleaned and organized longitudinal patient data (visits over time) and trained a deep learning model to learn patterns in disease progression, helping teams predict likely next complications/readmissions and plan follow-ups earlier.

Developed a forecasting model on large financial datasets to predict trends over time, and used feature importance/attribution to explain drivers, so analysts could understand why the model expects a rise/fall and make more confident decisions.

Set up a repeatable training and testing workflow (time splits and backtesting) to compare models across market periods, so the final approach was more stable in changing conditions and could be used as a reliable signal for planning and risk control.

Skills

HTML, CSS, TypeScript, JavaScript, Java, Scala, Python, Spring Boot, Spring MVC, Microservices, Node.js, Angular, React, Redux, REST APIs, JAX-RS, JSON, Kafka, Oracle, SQL, PostgreSQL,GraphQL, MongoDB, DynamoDB, DB2, Cassandra, Hive, HBase, AWS, EC2, S3, EMR, ECS, ECR, Athena, KMS, Lambda, Amazon CloudWatch, CI/CD, Airflow, Jenkins, Selenium, Docker, Kubernetes, Terraform, Linux, Jest, Cypress, JUnit, SonarQube, Splunk, Datadog, Git, GitHub, Jira, Agile, Scrum.

Certifications:

Microsoft Certified: Azure Developer Associate

AWS Certified Machine Learning – Specialty

Education

Master of Computer Science Wright State University, Dayton, OH, USA Apr 2023

Bachelor of Engineering in Electronics and Communication Engineering K L University, AP, India May 2019

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