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.
- Strong 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 actions to application workflows.
- Develop and maintain AWS Lambda functions and queue-based integrations for asynchronous event processing, validation, enrichment, workflow coordination, and downstream application updates.
- Implement reliable processing controls for idempotency, duplicate detection, retries, dead-letter handling, controlled concurrency, ordering where required, reconciliation, replay, and recovery.
- Develop and support React applications that use SMART on FHIR to present subscription-related workflows, launch within supported contexts, obtain authorized FHIR access, and interact with FHIR resources and application APIs.
- Develop and maintain NextGen Connect (Mirth) channels that receive, transform, validate, route, and acknowledge HL7 v2 messages and connect those workflows to FHIR resources, application services, and Enterprise Pub/Sub events.
- Validate Subscription, SubscriptionTopic, notification Bundle, and related FHIR resource instances against the applicable FHIR definitions, The Agency profiles, terminology, and business rules.
- Implement event correlation, structured logging, metrics, alerts, audit records, subscription health monitoring, and operational dashboards so teams can trace processing across publishers, Enterprise Pub/Sub, subscribers, and downstream applications.
- Create and maintain unit, integration, contract, conformance, interface, regression, end-to-end, performance, and failure-recovery tests covering FHIR subscription workflows, backend services, serverless processing, HL7 v2, and React components.
- Apply secure configuration, authentication, authorization, least-privilege access, privacy-aware logging, and appropriate handling of personal health information, and prepare technical designs, mappings, runbooks, and knowledge-transfer materials with project stakeholders.
DESIRED SKILLS:
- Experience implementing the FHIR R5 Subscription model or the R5 subscription backport for earlier FHIR releases, including SubscriptionTopic, rest-hook or WebSocket delivery, status notifications, heartbeat notifications, and event retrieval.
- Experience with AWS messaging, integration, and observability services such as Amazon SQS, Amazon SNS, Amazon EventBridge, Amazon API Gateway, and Amazon CloudWatch.
- Experience with infrastructure as code, automated build and deployment pipelines, containerized workloads, configuration management, and automated security scanning.
- Experience defining versioned FHIR profiles, event schemas, interface contracts, compatibility rules, correlation identifiers, and governance practices for shared enterprise integrations.
- Experience using NextGen Connect (Mirth) to integrate with Ontario digital health standards and provincial services, including the Hospital Report Manager (HRM) Standard, Provider Registry, Client Registry, and eReferral, with hands-on responsibility for HL7 v2 transformation, validation, routing, acknowledgements, conformance testing, and production support.
REQUIRED COMPETENCIES:
- Advanced FHIR Subscription and SubscriptionTopic experience, including resource triggers, filter criteria, lifecycle and status management, notification Bundles, delivery channels, heartbeat notifications, event retrieval, validation, and conformance testing.
- FHIR Subscription and SubscriptionTopic implementation experience for event-driven clinical workflows, including topic and event design, subscription filters and lifecycle management, notification Bundle processing, asynchronous queue processing, idempotency, retries, dead-letter handling, duplicate-event handling, observability, replay, and production troubleshooting using Java, Node.js, and AWS Lambda.
- React and SMART on FHIR experience, including launch and authorization flows, scopes, context handling, FHIR API integration, accessible user-interface development, automated testing, and secure handling of clinical information.
- NextGen Connect (Mirth), HL7 v2, and Ontario digital health standards experience, including the Hospital Report Manager (HRM) Standard, Provider Registry, Client Registry, and eReferral, covering message transformation, validation, routing, acknowledgements, error handling, interface and conformance testing, production support, and integration with FHIR, Java, Node.js, or serverless components.
RATED CRITERIA:
- 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. 25 Points
- 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. 25 Points
- React and SMART on FHIR experience, including launch and authorization flows, scopes, context handling, FHIR API integration, accessible user-interface development, and testing. 25 Points
- 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. 25 Points
Total: 100 Points
DELIVERABLES:
- FHIR SubscriptionTopic definitions and supporting artifacts that document event triggers, supported filters, notification content, delivery expectations, and conformance rules for assigned Enterprise Pub/Sub workflows.
- Subscription lifecycle components for creation, validation, activation, status management, renewal, deactivation, delivery configuration, heartbeat handling, event retrieval, and subscriber support.
- Updated Agency applications and workflows that integrate with Enterprise Pub/Sub and replace assigned polling-based processes with FHIR subscription-driven event processing.
- Production-ready Java and Node.js services, APIs, publishers, consumers, adapters, and integration components for managing subscriptions and processing FHIR events and notifications.
- AWS Lambda functions and queue-based processing components for validation, enrichment, retries, dead-letter handling, idempotency, duplicate detection, reconciliation, replay, and downstream updates.
- React components that use SMART on FHIR launch, authorization, context, scopes, and FHIR APIs to support the assigned subscription and application workflows.
- NextGen Connect (Mirth) channels and configurations for HL7 v2 ingestion, transformation, validation, routing, acknowledgement handling, error management, and integration with FHIR and event-processing components.
- FHIR profiles, examples, validation rules, event and interface mappings, contract tests, conformance tests, integration tests, end-to-end tests, and release-validation evidence.
- Structured logs, metrics, alerts, dashboards, subscription health monitoring, audit records, reconciliation controls, incident diagnostics, operational procedures, and production-support runbooks.
- Technical designs, API and interface specifications, workflow documentation, security and configuration notes, deployment instructions, demonstrations, release-support materials, and knowledge-transfer artifacts.
ADDITIONAL TERMS
The term of this Engagement Assignment is for 124 Business Days, with an option to extend for up to an additional 64 days at the Agency’s discretion. The Engagement Assignment may be extended for unused Business Days at the Agency’s discretion.
The resource will comply with the Agency’s policies and procedures.
The resource will be issued an Agency laptop and is expected to provide at least one additional monitor, an external keyboard and a mouse at their own expense. In addition, when the resource is working from their home location, they must have a private office space and are not permitted to work in an open communal space. Internet connection must be hard-wired and suitable bandwidth to support the IT requirements of this role. If these conditions cannot be met within their home office space, the resource will transition to full time in office, and the hybrid option will no longer be available.
The Agency systems cannot be accessed from outside the province of Ontario, and Agency assets including laptops and related equipment cannot be removed from the province of Ontario, without prior written approval from the Agency.
Knowledge Transfer Details:
- The resource will ensure full knowledge transfer is provided to the Agency team before end of engagement. Some of this might occur at the end of the engagement but will also be shared as information is obtained/consolidated. Key deliverables will be shared with team.
- The resource must provide all related documentation as part of knowledge transfer protocol. Documents will be reviewed by the appropriate leads and signed off by manager/director.
- The resource will work collaboratively with the Agency team throughout the assignment and ensure key deliverables, milestones, and documentation are shared.
- A walkthrough of any demos, development, etc. will be required before the end of the engagement.
