Full Stack Developer (Junior/Intermediate)

Reactiv; Toronto; Hybrid; CAD 65,000 - 90,000; Full time

Benefits offered by this job

Equity

Hybrid work

Extended health & dental

Unlimited PTO

Mentorship

Job summary

Reactiv is an AI-powered platform helping Shopify merchants build branded, high-converting mobile apps with minimal complexity. We are growing our engineering team and seeking a Junior to Intermediate Full Stack Developer to work on the dashboard, e-commerce APIs, and merchant-facing features.

You'll mainly use TypeScript across React on the frontend and Node.js on the backend, with opportunities to dive deeper into your preferred area in a collaborative, hybrid environment in Toronto.

Qualifications

• Working knowledge of React and core concepts.
• Experience building backend services or APIs with Node.js.
• Comfortable writing TypeScript or strong JavaScript.
• Understanding of RESTful APIs and how frontend/backend communicate.
• Relational databases like Postgres or MySQL.
• Strong problem-solving and team collaboration skills.
• Approximately 2–4 years of web app experience or equivalent projects.

Responsibilities

• Build and maintain features across the merchant dashboard with React/TypeScript and backend services in Node.js.
• Write and consume RESTful and GraphQL APIs connecting frontend to server-side functionality.
• Design simple schemas and queries in Postgres/MySQL, and optimize over time.
• Contribute to Shopify integrations to keep merchant data in sync.
• Collaborate with product, design, and engineers to ship new features.
• Improve performance and reliability on both frontend and backend.
• Participate in code reviews and fix issues across the stack.

Skills

React

Node.js

TypeScript

REST API

GraphQL

PostgreSQL

MySQL

Problem solving

Tools

Next.js

Jest

React Testing Library

OAuth

AWS

Shopify

Job description

Full Stack Developer
Junior / Intermediate

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 Full Stack Developer to help build and improve
the platform our merchants rely on every day, from the dashboard they use to design and
manage their apps to the e-commerce APIs that power them. 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 TypeScript across React on the frontend and Node.js on the
backend, with the chance to go deeper on whichever side excites you most. This is a
hands-on role for someone earlier in their career who wants to develop into a strong full
stack 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 features across our merchant dashboard React and TypeScript) and our backend services and e-commerce APIs Node.js and TypeScript).
• Write and consume RESTful and GraphQL APIs that connect our frontend experiences to server-side functionality.
• Work with relational databases such as Postgres: designing simple schemas, writing queries, and learning optimization along the way.
• Contribute to our Shopify integrations that keep merchant data in sync.
• Collaborate with product, design, and other engineers to define, design, and ship new features.
• Help keep the platform fast and reliable by improving performance and responsiveness on both sides of the stack.
• Take part in code reviews, both giving and receiving feedback, as part of how we maintain quality.
• Troubleshoot and fix issues across the stack to improve the experience for merchants.

What We're Looking For

Required

• Working knowledge of React and a solid grasp of its core concepts.
• Some experience building backend services or APIs with Node.js.
• Comfortable writing TypeScript, or strong JavaScript with a willingness to pick up TypeScript quickly.
• An understanding of how frontend and backend talk to each other: RESTful APIs, requests, responses, and error handling.
• Familiarity with relational databases such as Postgres or MySQL.
• Strong problem-solving instincts and eagerness to learn in a fast-moving, collaborative team.
• Roughly 2 to 4 years of experience building web applications, or equivalent project and portfolio work.

Nice to Have

• Experience with GraphQL.
• Familiarity with the Shopify ecosystem, or an interest in ecommerce.
• Exposure to AWS services Lambda, S3, RDS, DynamoDB or other cloud infrastructure.
• Experience with a React framework such as Next.js or React Router (formerly Remix).
• Experience writing automated tests Jest, React Testing Library, or integration tests).
• Understanding of authorization concepts such as OAuth and JSON Web Tokens.
• Familiarity with CI/CD practices.
• Exposure to React Native, or interest in contributing to mobile.

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 features 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.