Senior Full Stack Application Developer

Location Thornhill, Canada# Senior Full Stack Application Developer at Wellness Living Location Thornhill , Canada Salary $110000 - $130000 /year

Job Type Full-time

Date Posted January 7th, 2026

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*
* Title:

** Senior Full Stack Application Developer
** Salary:** $110,000 - $130,000 + Benefits + Vacation (exact placement within this range will depend on skills and qualifications)  
*
* Location:

** Thornhill, Ontario (hybrid)   
** Length:
** Full-time, permanent  At Wellness Living, we empower thousands of health and wellness business owners to turn their entrepreneurial dreams into reality. Our mission-critical software fuels their vision, supporting millions of clients around the world in their wellness journeys. With a deep commitment to putting our customers first, we foster a culture that values high performance, adaptability, and accountability. If you are a skilled professional who thrives in a fast-paced, customer-focused environment and are passionate about making a meaningful impact on the health and wellness industry, we would love to connect with you.
Our team is driven by four core values that shape everything we do. If you share these values and meet the qualifications outlined for this role, we encourage you to apply - we’d love to learn more about you!  
** Customer First**– We approach every challenge with a customer-focused lens, driven by an obsession with our customers’ happiness and success.  
** Excellence**– We approach every task, whether big or small, with a steadfast commitment to exceptional execution and the pursuit of greatness.  
** Accountability**– We take full ownership of our decisions, actions, and outcomes – both successes and failures.  
** Adaptability**– We recognize that sustained success demands that we be malleable and purposefully evolve, acknowledging that the world is dynamic and constantly changing.
*
* About the Role:

** We are seeking a
** Senior Full-Stack Application Developer to play a key,
** hands-on role in our microservices and domain-driven modernization journey. This role is ideal for an experienced engineer who combines strong frontend craftsmanship with backend and distributed systems thinking and has
** implemented** (not just discussed) modern cloud-native architectures.

You will design, build, and evolve
** scalable, event-driven, multi-tenant SaaS applications
** used across multiple brands in the healthcare and fitness technology space. You will work end-to-end, from React-based user experiences to secure APIs and microservices built with Node.js and Java (Spring Boot) while collaborating closely with product, architecture, Dev Ops, and data teams.

This role requires
** direct implementation experience**, an ownership mindset, and the ability to work effectively in an environment where systems are actively transitioning from monolithic patterns to domain-aligned microservices.
*
* Key Responsibilities:

**** Full-Stack Application Development
*** Design, develop, and maintain
** production-grade full-stack applications
** using
** React**,
** Node.js**, and
** Java/Spring Boot
*** Build modular, reusable frontend components aligned with
** design systems**, accessibility standards, and responsive UX best practices
* Develop secure, scalable
** RESTful and event-driven APIs**, ensuring performance, reliability, and backward compatibility
** Microservices, DDD & Event-Driven Systems
*** Implement
** microservices aligned to business domains and bounded contexts
*** Contribute to
** domain-driven design (DDD)
** discussions and translate domain models into working services
* Design and implement
** event-driven workflows
** using messaging or streaming platforms (e.g., Kafka, Kinesis, SNS/SQS)
* Apply patterns such as
** idempotency**,
** event versioning**, and
** eventual consistency
*** Implement and integrate
** modern authentication and authorization
** solutions using
** OAuth2, OpenID Connect (OIDC), and JWT
*** Work hands-on with identity platforms such as
** Auth0 and/or Fusion Auth
*** Design role-based and permission-based access controls suitable for
** multi-tenant SaaS environments
*** Build and deploy services using
** Docker, Kubernetes**, and
**…