Position: Software Developer - Full Stack – Senior

Type: Contract

Start Date: 2026-11-23

End Date: 2027-03-31

Location: Toronto

Work Schedule: Hybrid (onsite as required)

MANDATORY SKILLS

- Advanced FHIR Subscription and SubscriptionTopic experience, including resource triggers, filters, lifecycle and status management, notification Bundles, delivery channels, heartbeat notifications, event retrieval, validation, and conformance testing.
- Demonstrated FHIR Subscription and SubscriptionTopic implementation experience using Java, Node.js, AWS Lambda, and asynchronous queues, including topic and event design, subscription filters and lifecycle management, notification Bundle processing, idempotency, retries, dead-letter handling, duplicate-event handling, replay, observability, and production troubleshooting.
- React and SMART on FHIR experience, including launch and authorization flows, scopes, context handling, FHIR API integration, accessible user-interface development, and testing.
- NextGen Connect (Mirth) and HL7 v2 integration experience, including transformation, validation, routing, acknowledgements, error handling, interface testing, and integration with Ontario digital health standards and provincial services such as the Hospital Report Manager (HRM) Standard, Provider Registry, Client Registry, and eReferral
- Public Sector Experience: must have

Sr. Software Developer - Full Stack for integration with the Agency Enterprise Pub/Sub service

The Agency requires 2 Senior Full Stack Developers to support the Enterprise Pub/Sub Applications Team. The resources will update The Agency applications and associated workflows to integrate with the Agency Enterprise Pub/Sub service,



which is based heavily on FHIR Subscription and SubscriptionTopic.

The work will replace scheduled polling with subscription-driven event processing where appropriate so applications can respond when clinical information, referrals, reports, status changes, or other relevant events become available. The roles spans FHIR event architecture, backend, serverless integration, interface, and user-interface development.

The resource will define and implement FHIR Subscription and SubscriptionTopic behaviour; build Java and Node.js services, AWS Lambda functions, and queue-based event-processing components; develop React applications that use SMART on FHIR; and configure NextGen Connect (Mirth) channels for HL7 v2 workflows. The work includes subscription lifecycle management, filtering, notification handling, application and workflow changes, testing, monitoring, and transition of existing polling processes.

REQUIRED SKILLS:

- Strong hands-on experience with FHIR Subscription and SubscriptionTopic, including topic definitions, resource triggers, filter criteria, subscription status and lifecycle, notification Bundles, delivery channels, heartbeat notifications, and event retrieval.
- Senior-level experience developing Java and Node.js services, REST APIs, FHIR integrations, event publishers and consumers,



and production application logic.
- Robust experience implementing FHIR Subscription and SubscriptionTopic workflows with AWS Lambda and asynchronous queues, including notification Bundle handling, retries, dead-letter handling, idempotency, concurrency, duplicate-event handling, and replay.
- Strong React development experience building production applications that use SMART on FHIR launch, authorization, context, scopes, and FHIR API integration patterns.
- Hands-on experience with NextGen Connect (Mirth), HL7 v2 integration, and Ontario digital health standards and provincial services, including the Hospital Report Manager (HRM) Standard, Provider Registry, Client Registry, and eReferral, covering message transformation, validation, routing, acknowledgements, error handling, conformance testing, and production support.

RESPONSIBILITIES:

- Assess polling-based integrations and workflows, identify the clinical or application events that should trigger notifications, and map each workflow to the appropriate FHIR SubscriptionTopic and Subscription behaviour.
- Define, implement, and maintain SubscriptionTopic resources, including supported resource triggers, event definitions, filter parameters, notification shapes, and conformance requirements.
- Implement Subscription creation, validation, activation, status management, renewal, deactivation, delivery configuration, heartbeat handling, event retrieval, and subscriber lifecycle controls.
- Design, develop, test, and support Java and Node.js services that publish events, manage subscriptions, consume notification Bundles, call FHIR APIs, and route resulting actio

📌 Senior Full Stack Software Developer (Toronto)
🏢 Flexstaf I.T.
📍 Toronto