Senior Full Stack Engineer (B2B - Warsaw) at fresha

Location: Warsaw, Poland — Onsite (4 days on-site) Contract: B2B · 25–40 k PLN net / month + RSUs     The AI-powered OS for beauty, wellness and self-care Fresha is the operating system for the global beauty, wellness and self-care industry, connecting and powering everything from salons and barbers to spas, medspas, fitness studios and health practices. Marketplace + SaaS platform + Fintech   Fresha is the leading AI operating system trusted by millions of consumers and businesses worldwide. Fresha is used by 130,000+ businesses and 450,000+ stylists and professionals worldwide, processing over 1 billion appointments to date. Empowering businesses with an all-in-one platform for bookings, point-of-sale, marketing, and more, while connecting consumers to local services. Your Impact as a Full Stack Engineer   At Fresha, we believe AI is a force multiplier for feature delivery, not just a coding assistant. We provide every engineer with top-tier tooling (Claude, GitHub Copilot, Cursor) to strip away technical toil—so you can focus your energy on shipping high-impact product features. We value engineers who know how to leverage these tools to drive momentum within our 6-week cycles, accelerating the journey from concept to code while maintaining the deep technical judgment to verify, secure, and own the final user experience.    Are you ready to make a significant impact in a fast-paced, autonomous environment? We're seeking an exceptional Backend Engineer to join our cross-functional product team in Warsaw.   What You'll Do:   * Collaborate closely with Product, Design, Frontend, Infrastructure, and Mobile engineers to take features from discovery to rollout and beyond. * Be responsible for features from discovery to observability: technical design, implementation, testing, and rollout. * Design, build, and maintain efficient, scalable, and reliable Ruby/Elixir code. * Work with a polyglot stack (Ruby, Elixir, GraphQL, TypeScript, gRPC) and modern messaging systems (Kafka). * Operate within a Kubernetes-driven environment as we continue moving to a microservice architecture. * Embrace Domain-Driven Design to build high-quality, impactful products from inception to delivery.   To foster a collaborative environment that thrives on face-to-face interactions and teamwork, all Fresha employees work from the office four days per week, with the flexibility to work remotely on Wednesday each week. Warsaw: 20th Floor, Aleje Jerozolimskie 81, 02-001 Warsaw, Poland  What you will be doing • Frontend - Implement new functionality & UIs within our web frontend, which is written in React/NextJS • APIs - Design & document APIs in GraphQL & gRPC, which can be used by multiple consumers (within the team & by other teams) • Efficiency - Build & maintain efficient and developer-friendly APIs • Monitoring - Own the uptime & monitoring of our team-owned services • Problem-solving - Identify bottlenecks and bugs, and devise solutions to these problems • Lifecycle - Be involved in all stages of building products from inception, through delivery, to upkeep & operation • Culture - Contribute to a healthy engineering culture of feedback and growth This list is not exhaustive and there may be other activities you are required to deliver. What we are looking for • SPAs - Commercial experience in writing SPAs, especially using React • CSS - Experience implementing UIs with CSS, including GPU-only animations. Experience with RTL is a plus • GraphQL - Experience using and developing GraphQL APIs • Build Tooling - Experience working with and configuring typical javascript build tooling, such as webpack, esbuild, typescript, etc • Documentation - Ability to write easy-to-understand high-standard documentation • Communication - Strong communication skills, ability to self-organise and work well within teams • Environment - Comfortable working in a fast-paced and changing environment At Fresha, we value passion and potential as much as specific skills. If you're enthusiastic and eager to learn, we encourage you to apply, even if you don't meet every listed requirement. We believe in fostering growth and providing the support needed for you to excel in your role. Interview Process • Screen call - Video call with a member from the Talent Team - 30 - 60 minutes • 1st stage - Technical Video call/In-person interview with our Engineers- Up to 90 minutes • Tech stage - Technical Video call/In-person interview with our Engineers - up to 2 hours • Final stage - Video call/In person meet with our CTO - up to 60 minutes We aim to complete the entire interview process and deliver feedback within 4 weeks. Every job application received is reviewed manually by our talent team. While we strive to assess applications within 7 days, the sheer volume of talented individuals expressing interest may occasionally extend this timeframe