Client: Supply Ontario – RQ00828 We are seeking 2 Senior Full Stack Developers with extensive hands-on experience in FHIR Subscription and Subscription Topic implementations, Java, Node.js, AWS Lambda, asynchronous event processing, React, SMART on FHIR, NextGen Connect (Mirth), and HL7 v2 integration. The successful candidates will support the Enterprise Pub/Sub Applications Team in modernizing application workflows by replacing scheduled polling processes with subscription-driven event processing. The roles require strong expertise in FHIR event architecture, backend and serverless development, healthcare system integration, user-interface development, testing, monitoring, and production support, while ensuring secure and reliable handling of clinical information. Role Snapshot
- Job Title: RQ00828 – Software Developer – Full Stack – Senior
- Number of Positions: 2
- Client: Supply Ontario
- Work

Location:
525 University Avenue, Toronto, Ontario, Canada
- Work Arrangement: Hybrid (Onsite as required by the Hiring Manager)
- Estimated Start Date: November 23, 2026
- Estimated End Date: March 31, 2027
- Business Days: 124.00
- Extension: Option to extend for up to an additional 64 business days
- Hours: 7.25 hours per day, 5 days per week
- Assignment Type: Hybrid
-

Location:
Onsite as needed basis
- Public Sector

Experience:
Must Have Must Have
- Advanced FHIR Subscription and Subscription Topic 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 Subscription Topic 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 referral. Description 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 Subscription Topic. 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 span FHIR event architecture, backend, serverless integration, interface, and user-interface development. The resource will define and implement FHIR Subscription and Subscription Topic 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
- Solid hands-on experience with FHIR Subscription and Subscription Topic, 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 Subscription Topic 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 referral, 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 Subscription Topic and Subscription behaviour.
- Define, implement, and maintain Subscription Topic 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, Subscription Topic, 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 Subscription Topic, 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 Event Bridge, 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 referral, with hands-on responsibility for HL7 v2 transformation, validation, routing, acknowledgements, conformance testing, and production support. Required Competencies
- Advanced FHIR Subscription and Subscription Topic 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 Subscription Topic 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 referral, covering message transformation, validation, routing, acknowledgements, error handling, interface and conformance testing, production support, and integration with FHIR, Java, Node.js, or serverless components. Deliverables
- FHIR Subscription Topic 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 Notes Engagement Duration and Extension 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. Agency Policies and Procedures The resource will comply with the Agency’s policies and procedures. Equipment And Home Office Requirements 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 have 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 work, and the hybrid option will no longer be available. Geographical Restrictions 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. Assignment Type And Onsite Requirements This position is currently listed as "Hybrid". The resource under this request will be required to work onsite as per the Hiring Manager's sole discretion.

Location:
Onsite as needed basis. Public Sector

Experience:
Must Have.

How to Apply
If you are interested and

your profile
matches the requirements, kindly send the following mandatory documents to [email protected] by Monday, November 2, 2026, at 1:00 PM EST . Mandatory Documents
- Updated Resume in Word format (Mandatory)
- Skills Matrix and References (Mandatory)
- Expected Hourly Rate (Mandatory)
- Visa Status (Mandatory)
- LinkedIn ID (Mandatory) Without the mandatory documents, we cannot submit a candidate. Apply Online: Please visit our career website to apply for this opportunity. If you are interested in learning more about this opportunity, or if you know someone who may be interested, please feel free to forward this opportunity to them. WhatsApp Group For daily job updates, you can also join our WhatsApp group using the link below: Join our WhatsApp Group Email is the best way to reach us.

📌 – Software Developer – Full Stack – Senior (Toronto)
🏢 S M Software Solutions
📍 Toronto