Application Developer (Java, JavaScript) (Full-Stack)

This position is listed on behalf of a partner company, who manages all applications and next steps. Our partner is looking for an Application Developer (Java, JavaScript) (Full-Stack) based in the United States.

This role offers an opportunity to build the application services behind a public health IT monitoring and compliance evidence platform. You will develop Java-based services that ingest public health technology data, monitor published FHIR endpoints, validate resources, and generate reproducible evidence cases. Working across backend services, data pipelines, APIs, and supporting tools, you will help create reliable and repeatable endpoint observation workflows. You will implement deterministic validation rules that make compliance pass/fail decisions, while ensuring AI-assisted components only summarize and support analysis rather than determine final outcomes. The position combines Java and JavaScript development with AWS infrastructure, automated testing, and healthcare interoperability standards. You will collaborate with technical and engineering leads in a part-time, remote contract environment.

Accountabilities

• Build ingestion connectors for the Certified Health IT Product List (CHPL), Service Base URL Lists, developer-published FHIR Bundles, Lantern, and other approved public sources.

• Preserve raw source artifacts, timestamps, request metadata, response headers, and hashes to support traceability and reproducibility.

• Normalize developer, product, version, criterion, CHPL ID, endpoint, organization, and validation records into the project's common data model in DynamoDB, applying lineage and source-of-truth precedence rules.

• Implement publication checks that retrieve endpoint lists and classify availability failures, including URLs not found, timeouts, obscuring redirects, malformed responses, and non-machine-readable content.

• Build safe, non-authenticated endpoint observation capabilities for metadata and CapabilityStatement retrieval.

• Detect endpoint drift, including endpoints that are added, removed, moved, or changed.

• Run FHIR R4 validation against Endpoint, Organization, and Bundle resources, preserving both raw and normalized validation results.

• Assemble evidence case packages containing source metadata, request and response logs, validation outputs, severity assessments, and rule traceability.

• Support evidence deduplication, clustering, and export to Government-designated systems.

• Design and maintain scheduling, retry and backoff mechanisms, rate limiting, error handling, and audit logging for pipeline and agentic components.

• Ensure test runs are replayable so reviewers can reproduce and rerun tests associated with any evidence case.

• Develop unit and integration tests, including stub and mock endpoints to simulate failure scenarios.

• Participate in code reviews and maintain clear, current technical documentation.

• Enforce strict data-handling boundaries: do not request, collect, or store patient data, protected health information (PHI), credentials, or tokens unless explicitly authorized in writing by the Government.

• Maintain the separation between AI-generated summaries or drafts and deterministic validation logic responsible for final compliance determinations.

Requirements

• At least 5 years of Java 17+ development experience, including concurrency and networked services.

• At least 3 years of experience with Spring Boot or an equivalent framework.

• At least 2 years of JavaScript/Node.js experience for tooling and front-end development.

• At least 4 years of experience building REST APIs and working with JSON.

• At least 3 years of working knowledge of HTTP and TLS fundamentals.

• At least 3 years of experience with the AWS SDK, DynamoDB data modeling, and Amazon S3.

• At least 2 years of experience building and operating containerized services.

• At least 4 years of automated testing experience, including JUnit and integration testing.

• At least 3 years of experience conducting code reviews and producing technical documentation.

• At least 1 year of experience building with LLM APIs or using AI coding assistants in software development, including testing and validating AI-generated output.

• Authorization to work in the United States.

• Strong software engineering fundamentals, problem-solving skills, and attention to detail.

• Ability to develop reliable, secure, and repeatable services while working with technical specifications and data integrity requirements.

• Strong collaboration and communication skills, including the ability to work effectively with technical leads, engineering specialists, systems engineers, and project managers.

Preferred Qualifications

• Experience with HAPI FHIR or other FHIR R4 validation tools and standards, including US Core and CapabilityStatements.

• Knowledge of HTTP client internals, including timing and connection instrumentation.

• Experience designing scheduling, retry and backoff strategies, and rate-limiting mechanisms.

• Familiarity with Testcontainers, stub services, or mock services for failure testing.

• Experience with SMART on FHIR, Inferno, or ONC certification testing.

• Previous experience in health IT or federal programs.

Benefits

• W-2 hourly pay: $55–$60 USD per hour.

• 1099 hourly pay: $65–$70 USD per hour.

• Choice of W-2 or 1099 engagement.

• Remote work arrangement within eligible U.S. states.

• Part-time schedule of 10–29 hours per week, with variable hours.

• One-year contract opportunity.

• 401(k) with company match.

• Paid time off, increasing with length of service.

• Health, vision, and dental insurance.

• Company-provided life insurance and voluntary life insurance.

• Short-term and long-term disability coverage.