Internship Shopify App Developer Jobs in Toronto, ON

About Reactiv

Reactiv is an AI-powered platform that helps Shopify merchants build beautifully branded, high-converting mobile apps without the usual complexity. At the core of what we do is Reactiv Clips, a feature that removes the need for app downloads so brands can deliver fully customized app experiences instantly and without friction. By lowering the barrier to great mobile experiences, we're building the future of mobile commerce, and we're growing our engineering team to help shape what comes next.

About the Role

We're looking for a Junior to Intermediate Frontend Developer to help build and improve the dashboard that Shopify merchants use to design and manage their apps. You'll ship real features from early on, with support and mentorship from our engineering team to help you grow. Most of your work will be in React and TypeScript, building polished, accessible interfaces, with the chance to contribute to our React Native mobile app along the way. This is a hands-on role for someone earlier in their career who wants to develop into a strong frontend engineer in a collaborative, hybrid environment. You don't need to check every box below; if you're solid on the fundamentals and eager to learn the rest, we want to hear from you.

What You'll Do

• Build and maintain user interfaces for our merchant dashboard using React and TypeScript.
• Turn design specifications into clean, accessible, and responsive interfaces, working closely with our design team.
• Collaborate with product, design, and backend engineers to define, design, and ship new features.
• Occasionally contribute to our React Native mobile app as you grow.
• Help keep our frontend fast and reliable by improving performance and responsiveness.
• Take part in code reviews, both giving and receiving feedback, as part of how we maintain quality.
• Troubleshoot and fix issues to improve the experience for merchants.

What We're Looking For

Required

• Working knowledge of React and a solid grasp of its core concepts.
• Comfortable writing TypeScript, or strong JavaScript with a willingness to pick up TypeScript quickly.
• Experience building and maintaining user interfaces with React components.
• An eye for detail and a care for accessible, well-crafted UI.
• Strong problem-solving instincts and eagerness to learn in a fast-moving, collaborative team.
• Roughly 2 to 4 years of experience building web or mobile applications, or equivalent project and portfolio work.

Nice to Have

• Exposure to React Native, or interest in contributing to mobile.
• Experience with a React framework such as Next.js or React Router (formerly Remix).
• Familiarity with state management such as Redux, Zustand, or Context API.
• Experience with frontend build tools and workflows (Vite, Webpack, Babel, npm/yarn).
• Familiarity with CSS-in-JS libraries like styled-components or Emotion.
• Experience writing automated tests (Jest, React Testing Library).
• Understanding of RESTful APIs and GraphQL.
• Familiarity with the Shopify ecosystem, or an interest in e-commerce.
• Basic understanding of relational databases such as Postgres.

Why Join Us

• Mentorship and growth: You'll have regular code review, pairing, and support from experienced engineers, with a clear path from junior to intermediate and beyond.
• Level up with AI: We're constantly exploring how AI can make us better engineers, and you'll have real freedom to experiment with cutting-edge tools rather than wait for permission. It's a fast way to grow.
• Real impact: The interfaces you build are used by merchants running their businesses around the world.
• Hybrid work environment: We believe in a hybrid model to create opportunities for intentional in-person collaboration (and mentorship) while balancing that with the deep focus time that comes from working remotely. You'll join the team in our Toronto office 2 to 3 days a week with the flexibility to work remotely the rest of the time.
• You're an owner: Every engineer at Reactiv gets equity, so you share in the upside you help create. You're not just building the product, you own a piece of it.
• Benefits from day one: Extended health and dental coverage that kicks in the day you start, no waiting period.
• Unlimited PTO: We take time off seriously here. Most of our engineers take around three weeks a year, and more when they need it, and we actively encourage stepping away to rest and protect against burnout.

How to Apply

Send your resume and any project links, portfolio, or GitHub profile. A cover letter is optional, but we'd welcome a short note on why this role interests you.