Top Software Engineer Jobs in Toronto

Lead technical work enabling global-ready products: act as technical stakeholder, define roadmaps, remove major technical blockers, write and review high-quality tested code, mentor engineers, simplify abstractions, and collaborate across distributed teams to deliver scalable web/SaaS solutions.

Senior SDET responsible for designing and implementing automated test frameworks, executing system/E2E and performance tests, integrating tests into CI/CD, collaborating with engineers and product owners, mentoring junior staff, and driving test automation architecture and release activities.

Lead design, implementation, and operation of large-scale distributed scanning and data-collection services. Build and maintain services in Python and Go, improve performance, scalability, reliability, and observability, collaborate with security/product/data teams, diagnose production issues, drive architecture and roadmap decisions, and mentor engineers across a distributed team.

As a Senior Software Engineer, you will develop high-quality software applications, mentor teams, and drive project deliveries while collaborating with various stakeholders.

Lead design and delivery of platform capabilities for a federated GraphQL and event-driven architecture. Build and optimize gRPC endpoints, GraphQL APIs, and SQL/Postgres queries. Own observability (DataDog, Bugsnag), scalability, reliability, incident response, and integrations. Mentor engineers and drive cross-team technical efforts to reduce friction and accelerate product delivery.

Own IAM platform architecture and strategy, design OAuth2/OIDC flows and token lifecycle, drive cross-team technical decisions, de-risk and resolve production IAM issues, set engineering standards, mentor, and align with product and security stakeholders.

Own and advance a core Helius backend system supporting Solana infrastructure. Design and release high-performance products, optimize latency and throughput, make architectural decisions, improve observability and incident response, and mentor engineers. The role requires end-to-end ownership of production systems at scale, with close collaboration with founders and engineering leadership. Relevant systems include data streaming, historical APIs, account indexing, and access control infrastructure.

Own the technical direction of a core Helius backend system, including architecture, reliability, performance, roadmap, and production operations. Design scalable distributed systems, storage, streaming, or edge infrastructure; drive profiling and performance improvements; establish operational excellence; partner with founders on strategy; mentor engineers; and lead ambiguous cross-team initiatives.

Execute scheduled, ad hoc, and release-milestone software tests; review test cases; report defects in issue-tracking systems; communicate status in standups; and collaborate with software test managers and development teams. The role requires knowledge of QA methodologies, black-box, grey-box, and white-box testing, strong communication and organization, independent and team-based work, and participation in planning and professional meetings.

Build and maintain full-stack web applications and production LLM-powered features (RAG, agents). Develop evals, observability, API integrations, databases, background jobs, containerized deployments, and collaborate across product, design, and engineering to ship AI products.

Design, build, and own CI/build/test pipelines for a compiler/runtime/simulator stack; scale and parallelize large test suites, manage heterogeneous CI runner fleets and scarce hardware, implement perf-regression baselines and observability, and define hermetic, safe-by-default build and test standards to maximize developer velocity.

As an intern, you'll develop software and machine learning systems for robots, focusing on perception, intelligence, behavior, and real-time software integration.

Serve as the Tier 3 technical escalation owner: diagnose and fix code-level production issues across Node/TypeScript/AWS systems, deploy fixes, build runbooks, analyze incident trends, drive process improvements, and mentor the Application Support team.

As a Staff Full Stack Software Engineer, you will design and build foundational infrastructure, develop enterprise features, and ensure system reliability handling sensitive legal data.

As a Senior or Staff Software Engineer on the Localization team, you will design algorithms for state estimation systems, optimizing multi-sensor data fusion for real-time vehicle localization in autonomous driving.

As a Senior Software Engineer on the Mapping team, you will architect and develop robust, scalable systems for autonomous vehicle mapping, collaborating with multidisciplinary experts and handling complex data processing.

Design, implement, and maintain scalable C#/.NET applications; write tests and automation; mentor team members; participate in full development lifecycle, code reviews, debugging, and architecture decisions.

Develop software solutions, guide teams on cloud technologies, analyze requirements, resolve issues, and lead module execution while ensuring compliance with best practices.

Seeking a Senior Software Development Engineer in Test to architect and maintain test infrastructure, automation frameworks, and build CI/CD pipelines for cloud-based products. Responsibilities include mentoring, improving test strategies, and ensuring software quality and performance.

Design, build, and operate integrations, APIs, data exchange systems, and AI-enabled connections for accounting and ERP platforms. Own integration pipelines, SLAs, data contracts, observability, and production support. Provide technical direction through architecture reviews, code reviews, and pair programming while partnering cross-functionally on roadmap decisions. The role requires hands-on software development, scalable data architecture, secure integrations, experimentation, and participation in an on-call rotation.

Develop and optimize Elasticsearch performance across distributed and serverless architectures. Build performance models, profiling and benchmarking workflows, regression detection, and AI-assisted optimization harnesses. Analyze bottlenecks in logging, metrics, vector search, and ES|QL; implement scalable, thread-safe, high-performance Java code; and collaborate across teams through technical reviews and guidance. Experience with JVM internals, distributed systems, performance engineering, and benchmarking is required.

Lead architectural and code-level performance engineering for Elasticsearch. Own major optimization initiatives, develop performance models, profile distributed systems, identify bottlenecks, build benchmarks and regression detection, and improve scalability across stateful and serverless architectures. Develop AI-assisted optimization and benchmarking harnesses, collaborate across teams, and mentor engineers. Work includes Java and JVM optimization, concurrency, distributed systems, vector search, storage engines, and native library integration.

Architect and build production AI-powered HR systems using agentic workflows, multi-agent systems, APIs, and workflow automation. Integrate Workday and other HR tools, implement governance, audit logging, privacy controls, and human approval gates, and ensure reliable payroll-adjacent workflows. Document solutions, train People team users, drive adoption, and measure automation impact. The role requires strong software engineering, AI application development, HR technology, Workday, data privacy, and workflow automation experience.

Build and maintain high-throughput, low-latency backend services for Life360’s AdServer and Exchange platform. Own projects from architecture and implementation through deployment, improve real-time bidding and auction logic, integrate advertising partners, and support observability, incident response, and reliability. Collaborate with architects and product teams, use AI coding tools daily, mentor junior engineers, and contribute to engineering standards.

Design, build, and modernize high-scale, low-latency backend services and APIs for ad delivery. Work on distributed systems, performance, observability, cost efficiency, and architecture while collaborating with product, data, and engineering teams in a remote-first environment.