Python React Developer Jobs in Ontario (NOW HIRING)

Sitero is an emerging leader in Clinical services and software solutions for the life sciences industry. We have experience and expertise in a diverse range of therapeutic areas and focus on innovative, technology-enabled solutions that allow our clients to focus on their core strengths. For early phase studies through Phase III clinical trials, our experienced team delivers high-touch services and technology to ensure the safety of all stakeholders across the clinical research community with an emphasis on ethics, compliance, and innovation. 

Sitero is looking for a skilled Senior Software Engineer to primarily use Python to design, build, and maintain enterprise-grade features across our Life Sciences SaaS platform. You will work across the full technology stack — from crafting clean, responsive React frontends to building robust Python microservices — in a regulated environment that demands high code quality, security, and reliability.

As part of our Engineering team, you will collaborate closely with Product Management, QA, DevOps, and Clinical domain experts to deliver compliant, scalable software that supports clinical trials, pharmacovigilance, and patient safety workflows globally.

Job Title: Senior Software Engineer                           

Location: Mississauga, Ontario (Hybrid). 3x per week in office, 2x per week remote                

Function: Engineering                    

ESSENTIAL DUTIES AND RESPONSIBILITIES:

Full Stack Development

• Design and develop full-stack features using Python/FastAPI or Django (backend) and React/TypeScript (frontend)
• Build and maintain RESTful APIs and GraphQL endpoints consumed by internal and external systems
• Develop reusable, maintainable UI components and integrate them with backend services
• Participate in architecture reviews and contribute to technical design decisions

Backend Engineering

• Develop microservices following domain-driven design patterns and 12-factor app principles
• Implement secure authentication and authorization using OAuth 2.0, OIDC, and Python security libraries
• Optimize SQL/NoSQL queries, manage database migrations (Alembic), and design efficient data models
• Integrate with third-party APIs, HL7/FHIR standards, and clinical data systems where applicable

Quality & Compliance

• Write comprehensive unit, integration, and end-to-end tests (pytest, React Testing Library, Playwright/Cypress)
• Adhere to 21 CFR Part 11, HIPAA, and GxP standards in all development activities
• Support IQ/OQ/PQ validation activities and maintain traceability between requirements and code
• Participate in code reviews, enforce coding standards, and contribute to static analysis (SonarQube, Ruff/Black)

Collaboration & Delivery

• Work in Agile/Scrum sprints; contribute to sprint planning, grooming, and retrospectives
• Partner with QA on test planning, defect triage, and release readiness
• Document technical designs, API specifications (OpenAPI/Swagger), and runbooks
• Mentor junior developers and support onboarding of new team members

Technology Stack

Category

Technologies

Backend

Python 3.10+, FastAPI, Django/Django REST Framework, SQLAlchemy, Celery, Pydantic

Frontend

React.js, TypeScript, HTML5, CSS3/SCSS, Redux / Zustand, Vite/Webpack

Database

PostgreSQL, MySQL, MongoDB, Redis — query optimization & schema design

Cloud & DevOps

AWS (EC2, S3, RDS, Lambda) or Azure, Docker, Kubernetes, CI/CD pipelines

API & Integration

OpenAPI/Swagger, OAuth 2.0 / OIDC, Kafka/RabbitMQ, Microservices architecture

Testing

pytest, pytest-asyncio, React Testing Library, Playwright/Cypress, SonarQube, automated regression suites

Tooling

Git/GitHub, JIRA, Poetry/pip, VS Code / PyCharm, Agile/Scrum

EDUCATION AND EXPERIENCE REQUIRED:

• Bachelor's or master’s degree in computer science, Engineering, or a related field
• 5–8 years of professional software development experience
• Strong proficiency in Python 3.10+ and backend frameworks such as FastAPI or Django REST Framework
• Solid frontend experience with React.js, TypeScript, and modern CSS (SCSS/Tailwind)
• Hands-on experience with relational databases (PostgreSQL or MySQL) and query optimization
• Familiarity with containerization (Docker) and orchestration (Kubernetes)
• Experience with cloud platforms — AWS or Azure — and CI/CD pipeline management
• Strong understanding of RESTful API design, versioning, and documentation practices
• Working knowledge of Agile methodologies and tools like JIRA

Preferred Qualifications

• Experience in Life Sciences, Healthcare IT, or regulated software environments (GxP/21 CFR Part 11)
• Exposure to clinical data standards: CDISC, HL7 FHIR, or EDC/CTMS platforms
• Knowledge of event-driven architecture using Kafka or RabbitMQ
• AWS Certified Developer or equivalent cloud certification
• Familiarity with Python data science ecosystem (pandas, NumPy) or ML integrations
• Experience with AI/ML integrations or LLM-powered features in enterprise applications
• Contributions to open-source projects or published technical content

COMPENSATION & BENEFITS:

Salary range of $120,000-150,000 CAD

Sitero proudly offers an impressive compensation package and benefits through Canada Life, including a competitive salary, paid time off, and healthcare and retirement benefits.

EMPLOYMENT TYPE:

Full Time, Permanent

COMMITMENTS:

• Standard Hours 40 hours per week, one hour lunch, Monday – Friday. Additional hours as needed.
• 3x per week in office
• 2x per week remote from home

DISCLAIMER: 

Sitero is an equal opportunity employer and welcomes all job applicants.  All qualified applicants will receive consideration for employment without discrimination on the basis of race, color, religion, sex, sexual orientation, gender identity, national origin, protected veteran status, disability, or any other factors prohibited by law.