Python Backend Engineer Developer Jobs in Ontario

Principal Backend Engineer, Vice President Citi is looking for a Principal Backend Engineer to take strategic ownership of the backend systems powering a global digital experience platform that serves hundreds of thousands of clients and processes millions of web requests every day. In this role, you will set the technical direction for backend architecture, lead hands-on development of critical services, and shape the engineering standards that ensure the platform remains scalable, secure, and resilient at enterprise scale. You will work at the intersection of architecture, delivery, and technical leadership - influencing decisions that have direct impact on how Citi's clients and internal users connect with its digital ecosystem.

Responsibilities Define and evolve the backend architecture for an enterprise-scale digital platform, ensuring systems are built for scalability, reliability, and long-term maintainability. Design and build high-performance backend services and APIs in Java, covering core capabilities including user authentication, authorization, content routing, and data integration. Implement security-first engineering practices across all backend components, including single sign-on, centralized access control, and alignment with cyber defense standards.

Optimize platform performance through caching strategies, asynchronous processing, and efficient data access patterns to meet the demands of millions of daily transactions. Architect integration solutions that connect a broad range of content provider applications into the unified platform through secure HTTPS-based interfaces. Lead technical decision-making in collaboration with product management, front-end engineers, architects, and infrastructure teams to deliver features end-to-end.

Mentor senior engineers through structured code reviews and hands-on guidance, raising engineering standards across design patterns, testing, and operational practices. Serve as the technical escalation point for complex production incidents, leading root cause analysis and driving resolution for critical backend services. Required Qualifications & Skills 6 to 10 years of backend software development experience, with demonstrated expertise architecting and delivering large-scale enterprise platforms.

Expert-level proficiency in Java and its associated frameworks, applied to building high-performance, fault-tolerant services in production environments. Deep working knowledge of distributed systems, microservices architectures, and RESTful API design at scale. Hands-on experience implementing identity and access management solutions, including OAuth2 and OpenID Connect protocols and fine-grained authorization models.

Solid experience with cloud-native development using Docker and Kubernetes, and hands-on exposure to GCP and AWS environments. Working knowledge of both relational and NoSQL database technologies, with the ability to select and apply the right solution to complex data challenges. A bachelor's degree or equivalent practical experience, with a master's degree preferred.

Beneficial Skills & Qualifications Familiarity with additional backend technologies including Unix environments, Oracle databases, and distributed caching solutions. Experience integrating AI capabilities into backend services or workflows. Working knowledge of frontend integration considerations including ReactJS, Content Security Policy, corporate design systems, and accessibility standards.

What We Offer At Citi, you will work on technology that operates at a scale few engineering roles can match - shaping the backend systems that millions of users depend on every day. This is a role for an engineer who wants genuine technical ownership, strategic influence, and the opportunity to grow within one of the world's leading financial institutions. Hybrid working model with 3 days in the office and 2 days working remotely, giving you the structure of in-person collaboration alongside genuine flexibility.

Strategic technical ownership of backend systems with a global footprint, with the autonomy to drive architectural decisions that matter at enterprise scale. Access to continuous learning and development resources to deepen your technical expertise and grow your career at Citi. Competitive financial wellbeing offering, including compensation and benefits structured to reflect the seniority and impact of the role.

A collaborative, performance-driven environment where your engineering decisions have measurable impact on clients and colleagues worldwide. Wellbeing support and work-life balance initiatives designed to sustain high performance over the long term. Build the backend infrastructure that powers a global digital platform - apply now to bring your architectural expertise to Citi.

------------------------------------------------------ Job Family Group: Technology ------------------------------------------------------ Job Family: Applications Development ------------------------------------------------------ Time Type: Full time ------------------------------------------------------ Primary Location Full Time Salary Range: $120,800.00 - $170,800.00 ------------------------------------------------------ Most Relevant Skills Please see the requirements listed above. ------------------------------------------------------ Other Relevant Skills For complementary skills, please see above and/or contact the recruiter. ------------------------------------------------------ Automated Processing and AI We use automated processing, including artificial intelligence, for our legitimate business interests (or our reasonable and appropriate business purposes) to identify and align the candidate's skills and abilities with a specific job opening

Additionally, if you so choose, or consent, we can match your skills and abilities to other suitable roles at Citi. Importantly, all our hiring processes and decisions, including determining your suitability for a role, are conducted, checked, and decided by individuals. Our automated processing and AI do not involve relying on automatic or autonomous decision-making.

Please refer to any Jurisdictional Considerations, with specific provisions for your country (where relevant) for further details. ------------------------------------------------------ This job opening is for an existing job vacancy. ------------------------------------------------------ Citi is an equal opportunity employer, and qualified candidates will receive consideration without regard to their race, color, religion, sex, sexual orientation, gender identity, national origin, disability, status as a protected veteran, or any other characteristic protected by law.

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