Top Software Engineer Jobs in Montreal

Principal Full Stack Software Engineer responsible for guiding technical direction, designing large-scale SaaS features, and building secure, reliable distributed systems. The role involves collaborating across product, design, and engineering; evaluating technical trade-offs; debugging team inefficiencies; contributing to code reviews and complex fixes; mentoring engineers; and improving engineering practices around testing, performance, security, privacy, and service operations.

Build and ship full-stack web applications and scalable APIs for Affirm’s advertising platform. Break projects into deliverable phases, collaborate with product, design, and analytics partners, write tested and extensible code, monitor service metrics, support on-call operations, review code, and contribute to engineering growth and hiring activities.

Build and launch scalable backend systems and APIs for Affirm’s partner and merchant integrations. Responsibilities include breaking projects into deliverable phases, collaborating with product, design, and analytics teams, monitoring service health, participating in on-call operations, debugging code, conducting code reviews, and supporting team development. The role requires backend development experience with Python or Kotlin, distributed systems knowledge, and familiarity with AWS, MySQL, and Kubernetes.

Develop backend tools and systems that improve batch development, testing, and reliability. Responsibilities include breaking projects into deliverable phases, collaborating with product and infrastructure teams, monitoring system metrics, supporting on-call operations, writing tested and extensible code, debugging, participating in code reviews, and contributing to engineering growth activities.

Build and scale Affirm’s managed cache platform using Redis and Valkey. Responsibilities include cluster migrations, capacity and shard planning, failover and replication, upgrades, self-service automation, monitoring, SLOs, incident response, and advising teams on caching strategy. The role also involves designing tested backend systems, collaborating across engineering and product teams, participating in on-call operations, and contributing to code reviews and team development.

Build and improve high-traffic consumer web experiences using React and TypeScript. Develop experimentation, instrumentation, marketing integrations, attribution, and measurement systems while meeting privacy requirements. Collaborate with Product, Design, Marketing, Analytics, and Data Engineering, write tested and extensible code, monitor system metrics, support availability and on-call efforts, participate in code reviews, and contribute to team development.

Lead the technical direction and delivery of Bitcoin and stablecoin experiences for iOS across Cash App, Square, and Bitkey. Build and ship complex features end to end, establish architecture and shared systems, integrate backend services, improve testing and release safety, and mentor engineers. Collaborate across product, design, Android, web, and backend teams while applying AI-assisted development practices and contributing to secure, reliable customer experiences.

Lead technical direction and hands-on development of Bitcoin and stablecoin iOS products across Cash App, Square, and Bitkey. Own architecture, implementation, testing, service integration, rollout, observability, security, and post-launch improvements. Build foundational systems, mentor engineers, influence cross-team standards, collaborate across platforms, and integrate AI-assisted development tools while maintaining software quality and reliability.

Design and build backend APIs, microservices, and checkout platform components for Affirm’s financial products. Improve system performance, reliability, tooling, and engineering standards while collaborating across teams. Own components over their lifecycle, contribute to technical decisions, ship high-quality software at scale, and support peer development through communication and knowledge sharing.

Leads the technical direction and implementation of large-scale SaaS product features. Designs and builds secure, reliable, maintainable enterprise solutions using microservices and distributed systems. Collaborates cross-functionally on product strategy, debugs team inefficiencies, performs code reviews, resolves complex bugs, and improves engineering practices around testing, performance, security, and privacy. Mentors and coaches engineers while identifying organizational blockers and redundant efforts.

Build and operate full-stack compliance platforms for transaction search, entity labeling, ingestion, and workflow automation. Responsibilities include designing microservices and event-driven systems, writing tested code, improving sensitive financial data quality, building self-service tools and high-volume pipelines, partnering with Compliance and Risk teams, and participating in on-call operations. The role also involves using AI-powered development tools, reviewing code, and supporting engineering standards.

Develop and scale backend streaming and data infrastructure using technologies such as Kafka, Flink, AWS, and Kubernetes. Design, launch, test, and maintain distributed systems, monitor service availability, participate in on-call support, collaborate with product and engineering stakeholders, review code, and contribute to technical planning and team development.

Build and operate end-to-end full-stack features for Loom billing, subscriptions, integrations, and platform migrations. Develop responsive React interfaces, scalable backend APIs and microservices, payment and identity integrations, and reliable cloud-based systems. Responsibilities include observability, monitoring, testing, code reviews, documentation, security, performance optimization, and participation in Agile ceremonies and technical design reviews.

Lead the development of foundational iOS platform systems, shared frameworks, developer tools, architecture standards, and multi-quarter migrations across Cash App and Square. Drive performance, reliability, security, testing, observability, release safety, and AI-assisted development practices. This hands-on individual contributor role influences multiple teams, develops technical leaders, and partners broadly to improve iOS engineering quality, productivity, and product outcomes.

Design, build, and operate scalable backend services, APIs, and data models for Expedia's content and product catalog systems. Lead system and low-level design, end-to-end feature delivery, CI/CD, observability, incident response, and operational excellence. Collaborate with product, architecture, and engineering teams, mentor developers, and integrate AI/ML solutions to improve content quality, coverage, and developer productivity.

Build and launch backend identity decisioning systems that validate consumer identity and satisfy KYC requirements. Collaborate with Product, Compliance, Auth, Fraud, and engineering teams; break projects into deliverable phases; write tested, extensible code; monitor system metrics and availability; participate in on-call support, code reviews, interviewing, and team development.

Lead backend engineering work for Affirm’s lakehouse infrastructure, delivering reliable, scalable distributed data systems. Own quarterly goals, guide engineers through ambiguous problems, collaborate with product and analytics stakeholders, improve technical standards, monitor system availability, support on-call operations, and mentor team members. The role focuses on large-scale data platforms and technologies including Iceberg, Flink, Airflow, Spark, Kafka, Snowflake, AWS, MySQL, Kubernetes, and Terraform.

Design, build, scale, and operate high-volume payment APIs and distributed systems serving global traffic. Lead complex engineering projects from requirements through production, improve reliability, performance, observability, fault tolerance, and security, and participate in on-call and incident response. Collaborate across product and engineering teams, use AI-assisted development tools responsibly, and mentor engineers through technical reviews and documentation.

Design, build, scale, and operate high-volume payment APIs and distributed systems serving global traffic. Lead complex engineering projects from requirements through production, improve performance, observability, reliability, fault tolerance, and security, and participate in on-call incident response. Collaborate across product and engineering teams, use AI-assisted development tools responsibly, and mentor engineers through technical reviews, documentation, and guidance.

Design and maintain reliable ETL pipelines for fragmented financial-market data, normalize feeds into internal models, develop relational and time-series models for multiple asset classes, and build automated reconciliation and data-quality systems. Collaborate with quantitative researchers, traders, and engineering teams to deliver scalable reference-data infrastructure. The role requires strong SQL, Python or Java, Unix and shell scripting skills, financial instrument data knowledge, analytical problem-solving, and technical documentation or reverse-engineering experience.

Develop and improve Unity Editor tools, including Unity Search and Graph Toolkit, with smoother workflows, better performance, and intuitive interfaces. Build multi-context authoring and visual feedback features, write automated tests, collaborate with UX designers, gather user feedback, translate needs into software requirements, and resolve bugs. The role requires strong C# skills, Unity Editor expertise, automated testing experience, and openness to AI-assisted development tools.

Build backend data and measurement systems connecting marketing acquisition activity to signup, conversion, and GMV outcomes. Develop reliable pipelines, identity and event data systems, attribution capabilities, and marketing technology integrations while incorporating privacy, consent, and consumer-data requirements. Lead engineers through ambiguous problems, own quarterly goals, improve system reliability and code quality, collaborate cross-functionally, and mentor team members.

Own and evolve high-traffic consumer web experiences, experimentation, instrumentation, marketing technology integrations, conversion tracking, and measurement systems. Lead engineers through ambiguous projects, define technical plans, improve reliability and observability, support on-call operations, establish quality standards, and mentor team members. Partner with Product, Marketing, Analytics, Data Engineering, and platform teams to build performant, privacy-aware systems that address consent, cookies, tagging, and consumer-data requirements.

Develop and deliver full-stack web and mobile application experiences across Affirm’s consumer products. Responsibilities include breaking projects into tasks, collaborating with product, design, and analytics teams, building and maintaining APIs and user interfaces, monitoring application availability, participating in on-call support, conducting code reviews, debugging, and contributing to interviews and team development.

Lead fraud decisioning engineering initiatives, architect and build complex backend systems, write and review high-quality code, mentor engineers, coordinate cross-functional teams, and improve fraud detection through analytics and data-driven decisions. Responsibilities include technical planning, system design, delivery, monitoring, maintenance, stakeholder alignment, and participation in engineering hiring and interview development.