Client Industry: Healthcare Technology & Medicare Services
Engagement Type: Data Platform Modernization, Streaming Integration, Application Development
Core Technologies Delivered
- Cloud: AWS S3, Kinesis, Lambda, ECS
- Data: Spark, Elasticsearch, FHIR/HL7
- Backend: Java Spring Boot, C#/ASP.NET
- Frontend: React/TypeScript, Angular/NestJS
A St. Louis-based Keyhole Senior Consultant supported a national healthcare technology organization across multiple long-running initiatives focused on data platform modernization, real-time healthcare integrations, and mission-critical application development. The work spanned several systems and evolved alongside the client’s transition from on-premise infrastructure to AWS-based, cloud-native architectures.
Data Platform Modernization (St. Louis Healthcare)
The engagement began with a large-scale transition from legacy on-premise databases to AWS. Data sets were exported to Amazon S3, transformed using Apache Spark on EC2, and streamed through AWS Kinesis into AWS Lambda for conversion into FHIR-compliant data structures. The consultant designed and implemented a generic CSV-driven mapping library that dynamically converted result sets into FHIR object graphs, enabling flexible, repeatable data transformations without code changes. Processed data was stored in Elasticsearch for downstream access and analytics.
- Large-scale migration from legacy databases to AWS
- S3 exports → Spark transformations → Kinesis streaming → Lambda FHIR conversion
- Designed reusable CSV-driven mapping library for flexible FHIR object graphs (no code changes needed)
- Processed data stored in Elasticsearch for analytics access
Healthcare Application Development
The consultant later contributed to a patient care application used by St. Louis healthcare providers to ensure consistency of care year over year. The solution included a React and TypeScript single-page application hosted on AWS S3 and CloudFront, backed by Spring Boot services running in AWS ECS with DynamoDB persistence. As a vertical team member, the consultant worked across frontend, backend, and infrastructure concerns.
- Built patient care SPA for year-over-year consistency (React/TypeScript on S3/CloudFront)
- Backend Spring Boot ECS services with DynamoDB persistence
- Full-stack ownership across frontend, backend, and infrastructure
Enrollment & Insurance Systems
The focus shifted to a federal HIPAA-compliant Medicare enrollment application consisting of C# batch processing, an ASP.NET web application, and an MSSQL backend. The consultant supported all aspects of the system, including data processing, application logic, and ongoing enhancements critical to enrollment operations.
- Supported Medicare enrollment app: C# batch processing, ASP.NET web app, MSSQL backend
- Delivered data processing, application logic, and compliance enhancements
Real-Time HL7 Streaming Platform
In parallel, the consultant led work on a real-time healthcare integration platform that processed incoming HL7 message streams using Java Spring Boot microservices on AWS. The system leveraged Kinesis, Lambda, API Gateway, Aurora, and S3 to build mastered patient encounter records, transform them into FHIR Encounter objects, and securely publish them to partner systems via OAuth2-protected REST APIs.
- To support operational visibility, the consultant also built a monitoring dashboard using NestJS and Angular, deployed as microservices in AWS.
- Led HL7 → FHIR transformation pipeline using Java Spring Boot microservices
- Kinesis/Lambda orchestration with API Gateway, Aurora, S3 persistence
- Built NestJS/Angular monitoring dashboard for operational visibility
- Secure OAuth2 REST APIs for partner systems
Key Results Delivered
- Migrated legacy datasets to AWS cloud-native architecture
- Implemented reusable FHIR transformation library (zero code changes per dataset)
- Deployed real-time HL7→FHIR streaming with monitoring dashboard
- Full-stack Medicare enrollment enhancements for compliance
Across all initiatives, the engagement emphasized scalable cloud architecture, reliable streaming data pipelines, healthcare interoperability standards, and hands-on senior engineering ownership, enabling the client to modernize legacy systems while supporting critical healthcare operations.
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