Front End Engineer II

At Magnite, we cultivate an environment of continuous growth and collaboration. Our work impacts what millions of people read, watch, and buy, and we’re looking for people to help us tackle that responsibility with creativity and focus. Magnite (NASDAQ: MGNI) is the world’s largest independent sell-side advertising platform. Publishers use our technology to monetize their content across all screens and formats including CTV / streaming, online video, display, and audio. Our tech fuels billions of transactions per day!

We are looking for an Engineer II to join our Streaming UI team in Belfast. Our team is responsible for building the mission‑critical React applications that our publishers and account managers use to navigate the entire ad‑serving lifecycle—from managing high‑value inventory and deals to utilizing complex tools for diagnostics, reporting, and forecasting. As part of a global engineering powerhouse, you will play a key role in making the complexity of real‑time ad serving intuitive and actionable for our users.

You will be joining a predominantly engineering‑focused office in Belfast, working in close daily collaboration with our Streaming API teams across New York, Los Angeles, and Colorado. We are looking for a skilled React developer who is comfortable leveraging API and UI mocks to build seamless front‑end experiences. You should be a team player who takes pride in writing clean, unit‑tested code and is energized by the "golden hour" of collaboration (3 pm – 5 pm GMT) when our UK and US teams sync up to solve problems. We want someone who is unafraid to take responsibility and is passionate, fast, and detail‑oriented in their work. You will spend your time technically hands‑on—designing, coding, testing, and engaging with product and engineering peers to turn requirements into reality.

If this sounds like you, or the engineer you want to be, we want to hear from you!

In this role you will:

• Write production‑ready code and unit tests that meet both system and business requirements
• Respond to feature requests, bug reports, performance issues and ad‑hoc questions
• Work collaboratively with multiple teams to deliver quality software
• Support the operation of services in production

We’re looking for someone with:

• Extensive experience building and scaling modern, high‑traffic React applications
• Proficiency in front‑end data handling, including the ability to leverage API mocks and integrate seamlessly with RESTful services like Java Spring Boot
• Strong understanding of UI/UX implementation, with the ability to translate design mocks into high‑fidelity, responsive, and reusable components
• A proven track record of writing production‑ready code and comprehensive unit tests to ensure application stability
• Experience working in a collaborative, distributed engineering environment, specifically with U.S.-based cross‑functional teams
• The ability to be available during core overlap hours (3 pm – 5 pm GMT) for real‑time collaboration with teams in New York, Colorado, and Los Angeles
• Strong computer science fundamentals, including a deep understanding of browser performance, state management, and asynchronous programming
• A Minimum of B.S. in CS/EE, Math, Physics, or a related field
• The ability to balance high‑quality development with pragmatism and the rapid delivery of products
• Creative problem skills and someone who can navigate the complexities of ad serving tools like account dashboards and reporting tools
• The drive to want to work in an environment where software engineers are full participants in shaping the product and the business.
• Excellent communication skills and a "team player" mentality
• High attention to detail

Comprehensive Perks and Benefits:

• Holiday Breaks and Quarterly Wellness Days
• Equity and Employee Stock Purchase Plan
• Family‑Focused Benefits and Parental Leave
• Private Medical Insurance
• Competitive Pension Plan
• Disability and Life Insurance
• Mobile Phone Subsidy
• Fitness and Wellness Reimbursement