Senior Full Stack Developer

About Reactiv

Reactiv is building the future of mobile commerce. A world where the mobile web disappears, and every shopping journey becomes instant, contextual, and native.

Our platform lets brands turn any moment of intent - an ad click, QR scan, LLM search result, or real-world moment - into a fully personalized app experience with zero friction or downloads. Using Apple's App Clips, Reactiv gives marketers a new acquisition surface, a new retention channel, and a new way to build long-term customer relationships through high-intent, push-enabled experiences.

Beyond Clips, Reactiv provides the full stack for next-generation commerce: deep data integration, an AI-driven marketing engine, and tools that let brands deliver richer, higher-converting experiences everywhere their customers are. We're redefining how brands acquire, convert, and retain customers on mobile, and building the platform that powers the next decade of commerce.

If you want to help shape what comes after the mobile web, we'd love to meet you.

Position Overview

As a Senior Full Stack Developer at Reactiv, you'll play a pivotal role in our engineering team, focusing on the continuous enhancement of our Dashboard and Ecommerce APIs. This role involves a balanced mix of front-end wizardry and server-side expertise to develop new features, optimize performance, and maintain the scalability and security of our platform. You'll collaborate with cross-functional teams to translate business needs into technical specifications, creating an impactful user experience for our clients.

Key Responsibilities

• Feature Development & Integrations: Design, develop, and maintain high-quality, reusable, and reliable code across our Dashboard and E-commerce APIs, while owning and evolving integrations with Shopify and third-party services to deliver scalable, reliable synchronization and functionality for ecommerce clients.
• Optimization: Identify bottlenecks and bugs, and devise solutions to these problems to ensure the high performance and responsiveness of systems.
• Collaboration: Work closely with the UI/UX team to bring to life designed experiences with precision, ensuring they are intuitive and user-friendly.
• Testing and Maintenance: Implement robust testing environments and frameworks to ensure the reliability and security of the application.
• Mentorship: Guide and mentor junior developers, promoting best practices and a culture of continuous learning within the team.

Skills & Qualifications

Essential Skills

• Extensive experience in and TypeScript.
• Proficiency in React with a strong understanding of its core principles and workflows (such as Flux or Redux).
• Solid experience with relational and non-relational databases (such as MySQL, Postgres, DynamoDB), including schema design, queries, and optimization techniques.
• Strong experience with GraphQL, RESTful APIs, and server-side logic to integrate front-end elements with server-side functionality.
• Experience with Shopify platform, particularly developing and maintaining Shopify apps or integrations.
• Experience with security best practices, test-driven development, and integration and unit testing.
• Experience optimizing performance and abstracting solutions into reusable patterns that accelerate platform scalability and long-term growth.
• Strong problem-solving skills and the ability to make sound architectural decisions.

Desirable Skills

• Experience with , React Router or Remix is a significant plus.
• Hands-on experience with AWS services (Lambda, EC2, RDS, DynamoDB, S3, etc.) and understanding of cloud infrastructure best practices.
• Knowledge of modern authorization mechanisms, such as OAuth and JSON Web Tokens.
• Familiarity with front-end build pipelines and tools (such as Webpack, NPM, etc.).
• Familiarity with infrastructure as code tools (such as SST, CDK, Terraform, Pulumi).

Education & Experience

• 5+ years of experience in full stack development, with a portfolio that showcases your contributions to projects.