Senior Full-stack Developer (AI-Native)

Engg; Poland; On-site; PLN 200,000 - 320,000; Full time

Job summary

Xebia is seeking a senior full-stack developer to join a small product team building an AI-powered autonomous accounting platform for small businesses and accountants. You will own features end-to-end — from idea to API, data model, and customer view. Build AI agents and workflows in production, not pilots.

You will lead backend and frontend work, ship reliable AI-powered workflows, and collaborate with product, engineering, and domain experts to turn ideas into customer-ready features.

Qualifications

• 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 (Jest/Vitest).
• CI/CD and containerization (Docker).
• Experience with the cloud (AWS / GCP / Azure).
• Hands-on AI/LLM production experience: API usage, tool calling, streaming, or agent workflows.
• AI-native: experience with AI development tools (Cursor, GitHub Copilot, Claude Code).
• Ability to verify, debug, and refactor AI-generated code.

Responsibilities

• Build and improve the product experiences for small business owners and accountants.
• Develop backend services and integrations with accounting systems.
• Design and ship reliable AI-powered workflows and agent-driven features.
• Improve reliability, performance, and code quality.
• Collaborate with product, engineering, and domain experts to deliver value to customers.

Skills

Node.js

Express

TypeScript

React

Next.js

REST APIs

PostgreSQL

Data modeling

Jest/Vitest

CI/CD

Docker

AWS

GCP

Azure

AI/LLM production

Tool calling

Cursor

GitHub Copilot

Claude Code

Playwright

Cypress

Tools

Docker

Nx/Turborepo

Playwright

Cypress

GitHub Copilot

Cursor

Claude Code

Prisma

TypeORM

MongoDB

Redis

Job description

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