Senior Full-stack Developer (AI-Native) — Xebia

Xebia, a global AI-first digital transformation and engineering partner with 5,000 professionals across 16 countries, is hiring a Senior Full-stack Developer (AI-Native) for an on-site role in Bulgaria, Poland, or Romania to build an AI-powered autonomous accounting platform. The role requires at least 6 years of commercial fullstack experience, Node.js, TypeScript, React, Next.js, PostgreSQL, and hands-on production experience with LLM APIs, tool calling, streaming, and agent workflows, with daily use of AI development tools like Cursor, GitHub Copilot, and Claude Code.

Senior Full-stack Developer AI-Native - Salary - Not published - Location - Bulgaria; Poland; Romania - Work type - On-site - Level - Senior - Posted - today Apply on company site opens in new tab https://job-boards.greenhouse.io/xebiacee/jobs/6166532004 Xebia is a global AI-first, digital transformation, and engineering partner. With over 25 years of experience and a team of 5,000 professionals across 16 countries, we help organizations design and build scalable products, platforms, and data-driven solutions. We specialize in Artificial Intelligence, Data and Cloud, Intelligent Automation, and Digital Products, combining deep technical expertise with a strong focus on engineering excellence and a people-first culture. In the CEE region, we’re a team of nearly 1,000 experts delivering modern applications, data platforms, and AI solutions for clients such as McLaren, Aviva, Deloitte, Spotify, Disney, ING, UPS, Tesco, Truecaller, AllSaints, Volotea, Schmitz Cargobull, Allegro, InPost, and many, many more. We work with leading technologies including AWS, Azure, GCP, Databricks, and Snowflake, and combine strong engineering culture with a consulting mindset and a continuous focus on growth and knowledge sharing. Join a small, tight-knit product team building an AI-powered, autonomous accounting platform for the smallest businesses and the accountants who serve them. You'll own features end-to-end — from an idea in a conversation, through the API and data model, to what the customer actually sees and trusts. A core part of the work is building AI agents and the tools and workflows around them, in a product that's live in production, not a pilot. This is a Senior-level role. What you'll do - Build and improve the product experiences small business owners and accountants use every day - Develop backend services and integrations with the systems accounting runs on - Design and ship reliable AI-powered workflows LLM APIs, tool calling, streaming, agent flows where "usually right" is not good enough - Improve reliability and performance, and keep the codebase a good place to work - Work closely with product, engineering, and domain experts to take ideas all the way to customers You will be: - Minimum 6 years of commercial experience in fullstack software development - Backend: Node.js + Express, strong command of TypeScript - Frontend: React and Next.js SSR/SSG, App Router - Designing and building REST APIs GraphQL a plus - PostgreSQL - data modeling and query optimization - Testing: unit and integration tests e.g. Jest/Vitest - CI/CD and containerization Docker - Experience with the cloud AWS / GCP / Azure - Hands-on AI/LLM production experience: LLM APIs, tool calling, streaming, prompting, or agent workflows - AI-native: daily work with AI development tools e.g. Cursor, GitHub Copilot, Claude Code - Ability to verify, debug, and refactor AI-generated code Your profile: - Self-reliance and ownership - driving a task from analysis through to deployment - Ability to make architectural decisions and justify them - Clear technical communication with the team and stakeholders - Experience in a startup or small, fast-moving team Practical experience using AI-powered assistants e.g. Claude Code, GitHub Copilot, Cursor to improve productivity, quality, or decision-making in software delivery. Work from the European Union region and a work permit are required. Nice to have: - Experience with NoSQL databases e.g. MongoDB, Redis - Building AI features: RAG, embeddings, prompt engineering, agents - End-to-end testing Playwright / Cypress - Microservices architecture and monorepo experience Nx / Turborepo - Cloud certifications AWS/GCP/Azure - ORM familiarity e.g. Prisma, TypeORM -Experience applying GenAI in a more structured way within the SDLC, including defined workflows, prompt patterns, or tool integrations embedded into daily work. -Interest in and familiarity with emerging AI-driven practices e.g. agent-based workflows, automation patterns, AI-augmented development , with a willingness to explore and experiment beyond standard approaches. Recruitment Process: CV review – HR call – Interview – Client Interview – Decision