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

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.