At WHOOP, we're on a mission to unlock and inspire performance for life. WHOOP empowers members to perform at a higher level through a deeper understanding of their bodies and daily lives. The Growth team is responsible for accelerating member acquisition, activation, engagement, and retention through rapid experimentation and thoughtful product development. As a Software Engineer II (Backend), you’ll contribute directly to building and optimizing backend systems that power WHOOP’s growth initiatives. You’ll deliver high-impact features that directly influence member and business outcomes. You’ll work closely with Product, Design, and fellow engineers in a fast-paced, experiment-driven environment where iteration, measurement, and continuous improvement are core to how we build. RESPONSIBILITIES: • Collaborate closely with product managers, designers, and fellow engineers to develop scalable and reliable backend services. • Build, maintain, and optimize APIs and infrastructure supporting our acquisition funnels, e-commerce experiences, and membership growth experiments. • Write well-tested, maintainable code using technologies such as Java, Kafka, Postgres, and AWS. • Break down feature requirements into actionable tasks, prioritize work, and consistently deliver on sprint commitments. • Contribute to backend architecture discussions and implementation of scalable, high-availability services that support millions of users. • Work with data scientists and analytics engineers to support experimentation and measure performance. • Participate in code reviews and collaborate on best practices with your engineering peers. QUALIFICATIONS: • Professional backend engineering experience in a production environment. • Proficiency in building APIs and working with relational databases (e.g., RESTful APIs, Postgres). • Experience with event-driven systems and asynchronous processing tools such as Kafka or SQS. • Skilled in writing comprehensive tests and clear documentation. • Demonstrated ability to work cross-functionally and communicate clearly with technical and non-technical stakeholders. • A growth mindset and eagerness to learn from feedback and new challenges. • Bonus: Experience with A/B testing frameworks or growth-focused engineering initiatives.