Senior Full Stack Software Engineer Jobs in Ontario

Senior Software Engineer, Full-Stack Applications - AI Innovation Teams

As one of the world's top three credit ratings agencies, Fitch Ratings plays a critical role in global capital markets by providing credit analysis, ratings, research, and commentary to financial market participants. For over 100 years, Fitch Ratings has been creating value for global markets through its rigorous analysis and deep expertise, which have resulted in a variety of market leading tools, methodologies, indices, research, and analytical products. Fitch Ratings is part of Fitch Group, a global leader in financial information services with operations in more than 30 countries, which also includes Fitch Solutions. With dual headquarters in London and New York, Fitch Group is owned by Hearst.

Join our fastgrowing Toronto innovation hub, where we're building productiongrade AI to reshape global credit decisions. Here, you won't just ship features-you'll help reinvent an industry using decadesdeep proprietary data and a modern tech stack, free from heavy legacy. Backed by full enterprise support, you'll build reliable, explainable intelligence at real scale within a collaborative, outcomedriven community. If you're looking for purposeful work, constant learning, and a place where your impact and growth accelerate-this is where you'll thrive.

Want to learn more about our Toronto Innovation Hub? Visit: https://careers.fitch.group/go/Toronto-Innovation-Hub/9713801/

Fitch Ratings is seeking a Senior Software Engineer to join our new AI Innovation teams in Toronto-where we're building the AI-powered platforms and applications that will transform financial analysis. This isn't about maintaining legacy systems or making incremental improvements. This is about leading the development of what comes next: intelligent applications, full-stack platforms that seamlessly integrate cutting-edge AI capabilities, and user experiences that will fundamentally change how Ratings analysts work and how Fitch delivers insights to global financial markets.

We're at a defining moment. Fitch is making a major strategic bet on AI, investing heavily in Toronto as our innovation center, and we're building teams that combine exceptional full-stack engineers with world-class ML engineers. As a Senior Software Engineer, you'll own critical components of the applications and infrastructure that bring breakthrough AI to life-driving technical decisions, architecting scalable solutions, implementing backend services, and creating the integrations that make sophisticated ML models accessible and useful. You're joining at the perfect time to make significant technical impact while shaping the direction of transformative AI-powered platforms.

We need experienced full-stack engineers who understand AI's potential and can lead technical initiatives-not AI specialists, but seasoned technologists who can architect solutions that leverage generative AI, intelligent automation, and ML to transform workflows. If you're energized by "let's architect this the right way and push what's possible" rather than "this is how we've always done it," this is a high-impact role where you'll work alongside talented ML engineers, mentor engineers, and drive technical excellence in one of the most exciting areas of technology today.

What We Offer:

• Lead transformative full-stack applications with AI at the core - Drive architecture and implementation of net-new applications using Java/Springboot, Python, and REACT that integrate cutting-edge generative AI and ML capabilities; own technical decisions that enable elegant user experiences and bring intelligent automation to life
• Shape technical direction at the intersection of full-stack engineering and AI - Partner directly with ML engineers building breakthrough AI systems; influence architectural decisions; establish patterns for AI integration; mentor engineers while deepening your expertise in AI-powered applications that will define the next generation of financial technology
• Greenfield innovation with enterprise backing and ownership - Lead technical initiatives building net-new platforms from scratch with ownership of architectural decisions, modern frameworks, and cutting-edge technologies-backed by the resources, compute power, and organizational support that enable you to focus on building breakthrough solutions
• Toronto as Fitch's AI innovation hub - Be part of our strategic investment in Toronto as a center of excellence for AI-driven innovation; work in one of North America's most vibrant tech ecosystems alongside talented full-stack and ML engineers; establish yourself as a technical leader in this growing innovation center
• Strategic impact and high visibility - Own production applications that analysts and financial professionals use daily; see your architectural decisions directly enable sophisticated AI capabilities; drive systems that change how global financial markets operate; gain visibility through technical leadership and meaningful contributions
• Technical leadership and influence - Drive engineering best practices, mentor team members, participate in architectural reviews, and grow toward principal/architect/leadership tracks; opportunity to establish yourself as a thought leader in AI-powered applications with influence across teams
• Innovation-first culture with technical ownership - Drive experimentation with emerging technologies and shape technical direction; work with talented engineers who celebrate curiosity, embrace experimentation, and value your technical perspective and experience; environment where your leadership matters.

We'll Count on You To:

• Architect and lead full-stack applications - Design and drive implementation of scalable application features using Java/Springboot, Python, and REACT; own architectural decisions for user interfaces, backend services, APIs, and infrastructure; establish technical patterns that make AI capabilities accessible and maintainable
• Lead AI/ML integration architecture - Drive the technical approach for integrating generative AI, LLMs, and intelligent automation into full-stack applications; establish patterns for connecting ML models with user experiences; own technical decisions on how AI features are architected and implemented
• Champion engineering excellence - Establish and enforce engineering best practices, conduct code reviews, mentor engineers on code quality, drive CI/CD pipeline improvements, and lead technical discussions that balance innovation with reliability; own technical debt management and architectural improvements
• Drive technical decisions across teams - Lead collaboration with ML engineers, product managers, and business stakeholders; influence technical strategy; facilitate architectural discussions; and ensure alignment between AI innovation and application delivery through technical leadership
• Mentor and elevate team capabilities - Provide technical mentorship to engineers, lead knowledge-sharing initiatives, conduct design reviews, drive technical growth through thoughtful feedback, and contribute to building a culture of engineering excellence and continuous learning
• Balance innovation with pragmatic delivery - Drive features that move fast while establishing engineering standards; lead technical discussions on trade-offs; proactively identify and solve complex technical challenges; and own building applications that are both cutting-edge and production-ready
• Own production reliability and technical excellence - Lead troubleshooting of complex issues, drive system performance and scalability improvements, establish monitoring and observability practices, and own operational excellence of systems you architect

What You Need to Have:

• Deep full-stack engineering expertise - 12+ years of hands-on experience building web applications, with expert-level proficiency in Java, Springboot, Python, REACT, and modern web technologies; proven track record of delivering complex, production-quality full-stack solutions at scale
• Polyglot programming mastery - Extensive professional experience with both Java and Python; ability to drive technical decisions across different technology stacks and architect solutions that span diverse codebases
• Strong architectural and design expertise - Proven experience designing maintainable, scalable systems; deep understanding of design patterns, RESTful APIs, microservices, distributed systems; ability to make and own architectural decisions that impact multiple teams
• Bachelor's degree in Computer Science, Software Engineering, or related field (or equivalent experience)
• Mastery of modern development practices - Expert knowledge of software development fundamentals including test-driven development, advanced Git workflows, sophisticated CI/CD pipelines, and driving code quality across teams
• Leadership and collaboration skills - Proven ability to lead cross-functional teams, mentor engineers, influence technical direction, communicate complex technical concepts to diverse audiences, and drive alignment across ML engineers, product, and stakeholders
• Strategic mindset with AI understanding - Solid understanding of how AI/ML and generative AI can transform workflows; experience evaluating emerging technologies; comfort with technical ambiguity; track record of driving adoption of AI-powered capabilities in production applications
• Advanced problem-solving and technical depth - Exceptional analytical skills, experience navigating complex technical challenges, ability to drive multiple strategic initiatives, and proven success tackling sophisticated problems at the intersection of full-stack engineering and AI

What Would Make You Stand Out:

• Cloud-native architecture expertise - Deep hands-on experience with Docker, Kubernetes/EKS, AWS/Azure, microservices architecture, sophisticated CI/CD pipelines, and architecting cloud-native solutions at scale
• AI integration and production experience - Hands-on experience architecting and implementing AI/ML capabilities in production applications, working with LLM APIs, generative AI services, or building systems that leverage emerging AI technologies; proven track record making AI useful in production environments
• API architecture and system integration expertise - Expert experience designing scalable RESTful APIs, architecting complex integrations, designing asynchronous workflows, and creating robust interfaces between systems
• Advanced frontend architecture - Deep expertise with modern REACT patterns, complex state management, performance optimization, and architecting intuitive user experiences for sophisticated functionality
• Technical leadership in innovation environments - History of leading technical initiatives in fast-paced environments, driving architectural decisions for greenfield products, or owning technical direction in early-stage initiatives built from the ground up
• Mentorship and technical influence - Proven track record of mentoring engineers, driving technical growth across teams, leading code review culture, and establishing engineering best practices; recognized as a technical leader by peers
• Financial services or complex domain expertise - Deep understanding of analytical workflows, financial products, or complex business domains; experience translating business complexity into elegant technical solutions
• Technical thought leadership - Active participation in Toronto's tech community, speaking at meetups or conferences, contributing to open source, or recognized expertise in relevant technical domains
• Passion for engineering excellence and architecture - Drive high standards for architectural practices, clean code, comprehensive testing, and maintainable systems; recognized for technical craftsmanship and establishing quality standards
• Track record of technical evolution - Demonstrated history of driving technology adoption, leading architectural transformations, and expanding technical capabilities across teams and organizations.

If you're ready to lead the development of innovative AI-powered applications, dr...