Fullstack Product Engineer

Ship AI-native product experiments that improve conversion and retention We are hiring a Fullstack Product Engineer to own product experiments from user problem through production readback. Include “Product engineering is cool” in the subject line. Otherwise, your application will be disqualified. You will work across the application stack, use AI as a serious development tool, and make product decisions with real user and business data. The role rewards fast learning and strong engineering judgment, not raw code volume. About Single Grain Single Grain is a revenue marketing agency. We build pipeline-focused systems that compound, not campaigns that expire. We have helped more than 500 companies, from venture-backed startups to the Fortune 500, drive measurable growth. We operate as an AI-native team. Every role uses AI to improve speed, quality, judgment, and leverage. AI-generated code still requires sound architecture, testing, security, observability, and human review. Your mission Build and improve products that create customer value and convert more users into retained, paying customers. Primary KPI: increase trial-to-paid conversion from the current baseline toward 40%, while maintaining product quality and learning velocity. By month six, the target operating cadence is at least two meaningful product experiments per month. What you will own Turn user problems and product hypotheses into scoped experiments. Build production features across the front end, back end, dat