Senior Full Stack Engineer, Growth & Experimentation – Krak

Role overview Join a small product engineering team focused on growing a consumer finance app through rapid experimentation. You’ll mainly build in React Native and TypeScript, while contributing to backend services as needed so you can take ideas from hypothesis to launch, measurement, and iteration.

Responsibilities - Build and release customer-facing features and lightweight experiments across mobile products. - Partner with Product to identify opportunities in acquisition, onboarding, activation, engagement, and trading activity. - Design and run experiments across broad or market-specific audiences, then assess results and decide whether to iterate, scale, or stop. - Improve feature discovery and develop growth features that encourage customers to invite others or use more of the product. - Implement or adapt backend services and APIs when an experiment needs work across the stack. - Make technical and product decisions with limited upfront direction and changing priorities.

Requirements - At least six years building and shipping large-scale applications for consumers, including substantial React and React Native work. - A record of running growth experiments for consumer products and demonstrating results in conversion, activation, retention, or revenue. - Ability to design and implement backend services and APIs, with willingness to learn Rust. - Strong JavaScript and TypeScript skills, including experience with APIs, WebSockets, real-time systems, mobile performance, testing, and current development practices. - Experience designing and analyzing A/B tests, using feature flags and product analytics such as funnel and cohort data to guide decisions. - End-to-end ownership of product features and the judgment to work independently amid ambiguity.

Nice to have - Experience with customer-facing products in fintech, digital banking, payments, trading, or crypto. - Familiarity with Statsig or a similar experimentation platform, including regional and global rollouts. - Rust experience, SQL, or self-service analytics skills. - Experience with AI-assisted development, native mobile engineering, distributed systems, microservices, or large-scale consumer technology.