JavaScript/React Frontend Engineer with strong REST API + Java, .NET or Node.js - Only W2

Role: Javascript/React Frontend Engineer with strong REST API + Java, .NET or Node.js Location: NYC, NY (Hybrid - 3 days a week in office is must) Job Type: W2 Contract Experience Level: Senior Must-have JavaScript with React + strong Rest API experience with either Java, .Net or Node.js so needs to be fullstack. Job Description • Frontend-Focused Full-Stack Engineer (React + JavaScript) with strong Rest API experience with either Java, .Net or Node.js. • We are looking for Frontend-Focused Full-Stack Engineers to help enhance and scale a growing AdTech platform centered on digital advertising capabilities. • This role emphasizes modern frontend development with React and JavaScript, while contributing to backend integrations through REST APIs across multiple technologies (Java, .NET, Node.js). • You will play a key role in delivering high-performance user experiences for advertising platforms, including campaign management, targeting, measurement, and integrations across media and publishing ecosystems. Key Responsibilities Frontend (Primary Focus) • Design and build modern, scalable frontend applications using React and JavaScript (TypeScript preferred). • Develop intuitive UI/UX for key AdTech capabilities, including: • Campaign management dashboards • Targeting and personalization interfaces • Reporting and analytics views • Optimize frontend performance, responsiveness, and usability. • Collaborate closely with Product, Marketing, and Design teams to deliver high-quality user-facing features. Backend & API Collaboration (Secondary Focus) • Integrate frontend applications with REST APIs built in Java, .NET, or Node.js. • Contribute to API design discussions to ensure efficient frontend-backend interaction. • Support development and maintenance of backend services where needed, focusing on: • API contracts • Data flow optimization • Service integration Platform & Engineering Contribution • Help scale and enhance an existing AdTech MVP platform to enterprise-grade solutions. • Participate in system design discussions, code reviews, and technical planning. • Work with cloud-based and distributed systems. • Support CI/CD processes, deployment pipelines, and platform reliability. • Contribute to integrations with advertising platforms such as Google Ad Manager, Koddi, and similar ecosystems. • Assist in troubleshooting production issues and improving performance and stability. Required Qualifications • 6 8 years of software engineering experience, with strong emphasis on frontend development. • Strong expertise in: • JavaScript (ES6+) • React (including hooks, state management, component architecture) • Experience building complex, data-driven UI applications. • Experience working with: • REST APIs (integration and/or design) • Modern frontend tooling (e.g., Webpack, Vite, CI/CD pipelines) • Understanding of backend systems using one or more of: • Java • .NET • Node.js • Experience with cloud-based applications and services. • Familiarity with Agile development environments. • Understanding of CI/CD, DevOps practices, and application resiliency.