Senior Full Stack Developer (React, Node.js, JS & CSS)

Role Overview

Instrumental is hiring a Senior Full Stack Developer to join its growing international digital agency. This is a hands-on, fast-paced role building modern web applications, custom HubSpot solutions, and scalable backend systems. The role is full-time and remote or hybrid based on team needs.

Responsibilities

• Build and maintain applications using React and Node.js
• Develop HubSpot CRM UI Extensions and interactive front-end components
• Create serverless functions and custom-coded workflow actions using Node.js
• Develop and maintain HubSpot CMS themes, templates, and modules (training provided if needed)
• Ensure high-quality, performant, accessible web experiences
• Collaborate using project tools and workflows (e.g., ClickUp/Jira/Asana/Teamwork, Slack, GitHub)
• Work cross-functionally with designers and strategists to translate requirements into technical solutions
• Stay current with modern web technologies and best practices
• Engage thoughtfully with AI tools as part of everyday workflow (not to replace design craft)

Requirements

• 5+ years of professional full-stack JavaScript development
• Strong proficiency in React.js and state management (e.g., Redux, Zustand, Context API)
• Solid experience with Node.js (e.g., Express, serverless functions, API development)
• Strong modern CSS knowledge (e.g., SCSS, Tailwind, CSS-in-JS, Grid/Flex)
• Experience working with APIs and data fetching (e.g., Axios or similar)
• Strong Git workflow experience (branches, pull requests, code reviews)

Nice to Have

• Experience with HubSpot CMS/CRM development