Full Stack Engineer - Growth & Experimentation – Krak

Role overview Build and improve consumer-facing features for a mobile product, focusing on growth and experimentation. This frontend-leaning full-stack role uses React Native and TypeScript for rapid product changes, with enough backend work to carry experiments from idea to launch. You will partner closely with Product, measure outcomes, and decide what to expand, revise, or stop.

Responsibilities - Develop and ship small, high-velocity features in React Native and TypeScript. - Own experiments end to end, from hypothesis and implementation through rollout, measurement, and iteration. - Improve onboarding, activation, feature discovery, engagement, and trading activity through tested product changes. - Build acquisition and value-added features on top of existing product capabilities. - Implement backend services and APIs as needed to deliver experiments without waiting on another team. - Analyze test results and tradeoffs across conversion and other metrics, then make evidence-based decisions about next steps.

Requirements - At least three years building and shipping large-scale consumer applications, with strong practical React and React Native experience. - Demonstrated experience running consumer growth experiments with measurable effects on conversion, activation, retention, or revenue. - Backend skills sufficient to design and implement services and APIs; openness to working with Rust is expected. - Strong JavaScript or TypeScript fundamentals and experience with APIs, WebSockets or other real-time systems, mobile performance, and testing. - Practical A/B testing experience, including feature flags, statistical significance, product analytics, and funnel or cohort analysis. - Product-minded ownership and the ability to work autonomously amid ambiguity and changing priorities.

Nice to have - Experience in fintech, digital banking, payments, trading, or crypto products. - Familiarity with Statsig or a similar experimentation platform, Rust, SQL-based self-serve analysis, or AI-enabled development tools. - Native iOS or Android development, distributed systems, or work in a high-scale consumer technology environment.