Senior backend developer for FHIR healthcare web & mobile application

About the role

We’re building a clinically robust, FHIR-conformant backend for a gynecology/women’s health product. Our current Django backend is not fully HL7 FHIR compliant, you will correct it, and route payloads to a FHIR server (e.g., HAPI) for validation. The emphasis is on workflow correctness (Requests ↔ Events ↔ Definitions) and reliable front-end ⇄ backend linking, not on “just modeling resources.”

Your Tasks

Make our API FHIR-conformant

• Design/implement R5 resources (e.g., Patient, Encounter, ServiceRequest, Observation, Procedure etc.) with correct cardinalities, bindings, and references.
• Build Django/DRF serializers & mappers (ORM ⇄ FHIR JSON) and enforce code systems (LOINC/SNOMED/ICD-10).
• Stand up HAPI FHIR (Docker) and wire $validate into CI; reject non-conformant payloads.

Refactor & migrate existing data

• Audit current models/fields; produce a mapping matrix (legacy → FHIR).
• Write data migration/ETL to backfill or transform records into valid FHIR instances.
• Implement error handling for HAPI validation responses; create dev-friendly messages.

Harden the integration

• Add contract tests (pytest/Postman) with golden samples.
• Document resource profiles used, invariants, and example requests/responses.
• Optimize performance (pagination, search params, indexes; JSONB where helpful).

Tie into workflows

• Use basedOn/partOf consistently; add Task/Appointment where needed.
• Keep this pragmatic, focus remains on resource correctness.

Success in 30 days

• Endpoints emit/accept valid R4 resources; CI fails on $validate errors.
• A signed-off mapping spec (legacy → FHIR) and initial profiles (only where needed).
• Key resources live and clean: Patient, Practitioner, Encounter, Observation, ServiceRequest, Procedure, MedicationAdministration, Questionnaire/Response.
• Postman collection + pytest suite with sample payloads and automated validation.

Must-have qualifications

• Hands-on HL7 FHIR R4: you’ve built real resources (not just read about them), know cardinalities, references, bindings, terminology.
• Django/DRF expert: ORM modeling, serializers, viewsets, pagination, auth.
• Proven data mapping/normalization experience: from legacy schemas to standards; comfortable with migrations & ETL.
• HAPI FHIR (or Firely) experience incl. $validate, profiles, slicing basics.
• Strong API testing (pytest, Postman/Insomnia), Git-based CI.
• Portfolio of prior FHIR projects (links, code samples, or references).

Nice to have

• SMART on FHIR / OAuth2 (Keycloak), RBAC/consent.
• Terminology services (e.g., VSAC/SNOMED server), IG Publisher/Simplifier.
• Bulk Data (NDJSON), PostgreSQL JSONB, Celery/RQ, OpenAPI, observability.