Senior Frontend Developer - React+ AI experience (all genders)

Senior Frontend Developer

Lightspeed is looking for a Senior Frontend Developer to join our team. As a frontend engineer, you will support Lightspeed's mission to build intelligent, AI-powered tools and capabilities that transform how our teams and customers work.

For this role specifically, you will join our Agent OC Squad. This squad is focused on bringing generative AI capabilities directly into our product — building features that provide real value to customers by leveraging LLMs, agent frameworks, and other emerging AI technologies where they can make a meaningful difference. At the same time, the team establishes the foundations, best practices, and platform patterns that enable other internal teams to do the same. You'll be actively building generative AI features into the product while shaping the standards and tooling that scale AI adoption across the organization.

Above all, your work will help shape the future of intelligent automation at Lightspeed!

Who You Are

• You're a frontend engineer who is excited about AI and eager to explore how LLMs and agents can reshape user experiences.
• You thrive in ambiguity and enjoy the challenge of building something from scratch on a new team.
• You take ownership of outcomes, not just code — you care about what gets built and why.
• You are self-motivated and can function effectively in a team environment with minimum supervision.
• You are always seeking improvement and progress, and you care deeply about building reliable, intuitive user experiences.

What You'll Be Responsible For

• Designing and Building AI-Powered Interfaces: Design and build intuitive frontend interfaces that effectively expose AI and LLM capabilities to users and partners.
• Frontend Architecture for AI Workflows: Create scalable, performant React-based UIs that handle asynchronous and long-running operations, streaming responses, and real-time agent interactions.
• Product Thinking and Ownership: Contribute to product direction and roadmap for AI-powered features, helping define what to build and why — not just how.
• Cross-Functional Collaboration: Work closely with backend engineers, Product Managers, and Designers to integrate AI features and ship products that delight users.
• Component Development and Quality: Build reusable, well-tested React components with a focus on performance, observability, and platform reliability.
• Knowledge Sharing and Mentorship: Support your peers, share knowledge, and raise the engineering bar through code reviews and mentorship.

What You'll Be Bringing to the Team

• Outstanding JavaScript/TypeScript knowledge with 5+ years of production experience, including expert-level React.js and modern frameworks (Next.js, etc.).
• Proven technical leadership and ability to set frontend technical direction.
• Strong understanding of API integration patterns, data fetching strategies, and frontend performance optimization.
• Commitment to code quality — clean, maintainable, well-tested code with strong testing practices and accessibility standards.
• Experience with modern styling approaches (CSS Modules, Tailwind, CSS-in-JS) and web components / shadow DOM.

What will increase your chances:

• Experience with AI-powered frontend development: agent SDKs (Vercel AI SDK, assistant-ui), Generative UI concepts, or LLM API integrations.
• Familiarity with real-time communication (WebSockets, streaming) and AI-specific patterns (RAG, vector search, semantic retrieval).
• Experience building responsive, adaptive interfaces such as chat UIs, conversational flows, or backend-for-frontend architectures.
• Experience contributing to or working with open-source frontend or AI projects.
• Familiarity with cloud infrastructure (AWS, GCP), CI/CD systems, Docker, or observability tooling.

What's in it for you

• Lots of autonomy, flexible work culture
• Genuine career growth opportunities within a company that's continuously expanding
• Make a meaningful impact by helping teams and customers work more effectively with AI
• Be part of a team large enough for growth yet agile enough for real impact
• Work on high-traffic products with a global user base
• Opportunity to work alongside other highly skilled engineers, learn and expand your skill set, forge wonderful relationships and make your mark within the diverse and inclusive Lightspeed culture, a true Canadian tech success story

… and enjoy a range of benefits that'll keep you happy and healthy:

• Lightspeed share scheme (we are all owners).
• Flexible working policy.
• Mental health online platform and counseling & coaching services.
• Health and wellness benefits.
• LinkedIn Learning license (learning is always ongoing).
• Volunteer day to be able to give back to society!

Lightspeed is a proud equal opportunity employer and we are committed to creating an inclusive and barrier-free workplace. Lightspeed welcomes and encourages applications from people with disabilities. Accommodations are available on request for candidates taking part in all aspects of the selection process.

Where to from here?

Obviously, this has to be mutually beneficial: we want you to step into a role you love, and we want to offer you a place you're proud to come to every day. For a glimpse into our world check out our career page here.

Lightspeed is building communities through commerce, and we need people from all backgrounds and lived experiences to do that. We were founded in 2005, in Montreal's gay village and our original members were all part of the LGBTQ+ community. The ethos of our business has been about inclusion from the very beginning, and we strive to provide a workplace where everyone belongs.

Who we are:

Powering the businesses that are the backbone of the global economy, Lightspeed's one-stop commerce platform helps merchants innovate to simplify, scale, and provide exceptional customer experiences. Our cloud commerce solution transforms and unifies online and physical operations, multichannel sales, expansion to new locations, global payments, financial solutions, and connection to supplier networks.

Founded in Montréal, Canada in 2005, Lightspeed is dual-listed on the New York Stock Exchange (NYSE: LSPD) and Toronto Stock Exchange (TSX: LSPD). With teams across North America, Europe, and Asia Pacific, the company serves retail, hospitality, and golf businesses in over 100 countries.

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