Top Software Engineer Jobs in Toronto

Lead architecture and evolution of Juniper Square’s distributed services, cloud infrastructure, and developer platform. Design scalable, multi-tenant, event-driven systems; build paved-road developer tooling, CI/CD, and observability. Hands-on coding, prototyping, and performance troubleshooting. Enable production AI/LLM workloads, ensure security/compliance, support enterprise upmarket needs, and mentor engineering teams to raise operational excellence and reliability.

Design, develop, and optimize adaptive radiotherapy desktop software: DICOM integration and networking, 3D image processing, deformable registration, coordinate transforms, dose visualization and DVH evaluation. Build performant WPF applications under near real-time constraints, integrate with oncology systems, collaborate with physicists and product, contribute to architecture, testing, code reviews, and mentor teammates.

Build and operate backend systems enabling enterprise deployments of Coder. Design and implement scalable backend architecture, improve upgrade and migration reliability, investigate and resolve production scalability issues, own operator-facing backend features, document tradeoffs, participate in design reviews and on-call rotations.

Design, build, and productionize LLM-powered applications and agentic AI systems. Develop data and inference pipelines, deploy and monitor models, define evaluation frameworks, optimize performance/cost, and enforce governance, safety, and observability to deliver scalable AI-driven customer experience solutions.

Develop and maintain backend services and RESTful APIs for a credit card and payments platform. Work across the full stack with MySQL and third-party integrations, debug production systems, collaborate on feature design, and learn the payments domain while shipping production code.

Lead architecture and development of scalable, secure full‑stack services for card and payments systems using PHP and Python. Design REST APIs and microservices, optimize MySQL performance, drive CI/CD and testing standards, champion security and compliance, influence AI tooling strategy, and mentor mid and junior engineers.

Work directly with clients to scope, prototype, and deploy AI-powered workflows. Build scalable systems using LLMs, embedding and retrieval systems, and backend infrastructure. Translate messy data and operational constraints into production-ready solutions, iterate with stakeholders, and maintain deployed systems (including on-call support).

Develop and optimize auto-labelling systems using ML and computer vision, manage data pipelines, and collaborate with researchers.

The Senior Software Engineer will develop automation tools for marketing campaigns, build applications on Google Cloud, and work in an agile team. Responsibilities include mentoring, creating APIs, and contributing to design decisions with a focus on best practices.

Design and implement infrastructure solutions for reliable, scalable data-intensive systems, optimize PostgreSQL databases, and enforce Infrastructure as Code best practices.

Lead design, build, and operation of scalable AI-enabled backend services and data pipelines that extract and resolve information from semi-structured legal documents. Develop LLM-powered workflows, improve citation recognition and resolution, ensure observability and security, collaborate with cross-functional partners, and mentor engineers while owning production lifecycle and reliability.

Manage and lead a team of engineers, oversee software development for ML platforms, and ensure high-quality project execution while collaborating across teams.

Develop scalable systems across product and infrastructure, lead architecture decisions, mentor engineers, and improve system performance using various technologies.

The Principal Software Engineer will design and build scalable platform services for the authorization platform in a healthcare context, mentor team members, and drive architectural decisions.

Lead design and delivery of end-to-end software architecture for machine HMI stacks. Provide technical and functional leadership, review code and architecture, mentor developers, make technology decisions (performance, safety, scalability), contribute hands-on in Angular, graphics, Python/C++, and system integration, and improve development processes and quality assurance.

Build developer tooling, demos, and integrations to enable secure AI agent experiences; contribute to open source; lead architecture, documentation, and cross-functional work to ensure secure, resilient agent-to-service systems.

Lead the design, implementation, and operation of core developer infrastructure (build systems, CI, SCM, remote dev envs). Drive architecture, scalability, onboarding improvements, standardize CI/build patterns, mentor engineers, and improve engineering productivity and reliability at scale.

Build and maintain scalable Python back-end microservices and data pipelines supporting document ingestion, RAG/IR systems, vector indexing, and LLM-powered knowledge services. Optimize performance, observability, APIs, and cloud deployments for production SaaS environments.

Set architectural vision and implementation strategy while remaining hands-on across the full stack (.NET Core/C#, Angular). Design and develop scalable REST APIs, enforce architecture guidelines, mentor engineers, drive cross-team initiatives, own CI/CD and DevOps practices, and champion AI-assisted development and AI feature integration into the product in partnership with Product and Operations.

Build and maintain scalable web applications and backend services using React, TypeScript, Next.js and Node.js. Design APIs (REST, gRPC, GraphQL), work with PostgreSQL and cloud infrastructure, improve CI/CD and developer tooling, contribute to architecture, mentor engineers, and deliver AI-powered features and CRM workflows.

Build and operate Wealthsimple's ML platform to take models from experimentation to production: design architecture, build framework-agnostic training/inference services, ensure scalability and observability, enable self-serve tooling for data scientists, and own long-lived ML infra projects (Kubernetes, Ray, LLM integrations).

Design, build, and operate public-facing REST APIs and integration platform components. Implement platform standards (auth, rate limiting, versioning), bulk/batch sync, contract testing, CI/CD, SDKs, and integration marketplace workflows. Own production services end-to-end (monitoring, on-call, incident response) and improve reliability, performance, and developer experience for enterprise integrations.

Lead architecture and core runtime foundations for a distributed scanner platform, driving reliability, observability, performance, and engineering rigor while collaborating with hardware and ML teams and mentoring engineers.

Lead design and implementation of high-scale backend systems powering real-time reservation availability. Drive product features and infrastructure upgrades, build and optimize microservices for multi-data-center scalability, enforce reliability through automated testing, collaborate via code reviews and pair programming, and adopt AI technologies responsibly.

Lead design and implementation of AI-driven data analytics platforms and pipelines for Lyft's Marketplace. Define architecture and roadmap, build backend microservices and APIs, drive AI innovation (agentic workflows, model evaluation, causal models, anomaly detection), collaborate with product and data teams, resolve incidents, and mentor engineers to improve business operations and metrics governance.