machine learning engineer for rewards platform

The company operates a bootstrapped rewards platform with 80 million users and has been profitable since day one. Its machine learning models directly influence user engagement and company earnings.

• Design and ship production machine learning models that directly impact user engagement and company earnings;
• Translate complex mathematical business problems into concrete ML formulations;
• Build and optimize reward and payout structures, balancing user motivation with cost sustainability and advertiser value;
• Diagnose and troubleshoot underperforming reward campaigns, identifying root causes and implementing solutions;
• Contribute to the design and implementation of core ML infrastructure, including training pipelines and live model serving.

• Hands-on experience shipping production ML models end-to-end;
• Experience working across data pipelines, models, and live serving;
• Strong grounding in statistics, including A/B testing, regression, and probability;
• Motivation by business impact as well as technical elegance, with a focus on high-leverage solutions;
• Willingness to build ML infrastructure alongside the team rather than only use existing systems;
• Nice to have: causal inference or uplift methods.

• London, England, United Kingdom.