Principal/Senior Software Engineer

Engg; Poland; On-site; PLN 140,000 - 190,000; Full time

Job summary

Xebia is seeking a senior software engineer to drive the design and development of production-grade full-stack applications, with a focus on TypeScript, JavaScript, React, and backend runtimes like Node.js or Deno.

You will collaborate across product, architecture, and platform teams, implement secure APIs, data models in PostgreSQL, and leverage cloud-native services like Supabase while embracing CI/CD and observability.

Qualifications

• 10+ years of professional software engineering experience.
• Strong hands-on expertise in TypeScript and JavaScript.
• Experience with React and backend runtimes such as Node.js or Deno; PostgreSQL data modeling.

Responsibilities

• Lead design and development of full-stack enterprise apps.
• Design and integrate REST APIs and webhooks; ensure security and performance.
• Mentor engineers and promote best practices across teams.

Skills

TypeScript/JavaScript

React

Node.js/Deno

PostgreSQL

CI/CD

Tools

Supabase

REST APIs

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.

You will be:

• designing and developing production-grade full-stack web applications and enterprise software, providing hands-on technical leadership and helping establish engineering patterns, standards, and best practices, translating product requirements and emerging ideas into pragmatic, scalable technical solutions, working across frontend and backend, with a strong focus on TypeScript, JavaScript, React, and Node.js or Deno, designing and integrating REST APIs, webhooks, event-driven integrations, and third-party SaaS platforms, contributing to technical decisions around authentication, authorisation, data access, security, performance, and reliability, mentoring engineers, sharing knowledge, and helping raise engineering capability across the team, collaborating with Product, Architecture, Platform Engineering, and other engineering teams, experimenting with emerging technologies and turning successful prototypes into production-quality solutions, supporting modern CI/CD, testing, observability, and production engineering practices.

Your profile:

• 10+ years of professional software engineering experience, ideally across modern full-stack web applications and enterprise products, strong hands-on expertise in TypeScript and JavaScript, with significant production experience in React and backend runtimes such as Node.js or Deno, solid experience with PostgreSQL, including data modelling, querying, performance, and application integration, as well as Supabase or comparable cloud-native / Backend-as-a-Service platforms, including authentication and data access controls such as RLS, strong experience designing and integrating REST APIs, webhooks, event-driven solutions, and third-party SaaS platforms, including OAuth 2.0 and secure API integrations, strong understanding of modern authentication, authorisation, permissions, and secure application design, experience with modern frontend development patterns, automated testing across unit, integration, and end-to-end levels, and responsive application design, strong understanding of CI/CD, Git-based workflows, and modern SDLC practices, with experience deploying and supporting production applications with a focus on observability, performance, reliability, security, and operational readiness, excellent problem-solving and debugging skills, particularly across complex full-stack and third-party integration scenarios, strong communication and collaboration skills, with the ability to work effectively across engineering, product, architecture, and platform teams, automation-first and product-focused mindset, comfortable working with emerging technologies while maintaining the engineering discipline required to operate software at enterprise scale, practical experience using AI-powered assistants (e.g. Claude Code, GitHub Copilot, Cursor) to improve productivity, quality, or decision-making in software delivery.

Nice to have:

• experience using LLM APIs, AI SDKs, or developing AI-enabled applications, familiarity with the Vercel ecosystem, TanStack Query, React Router, Tailwind CSS, or shadcn/Radix, experience working with developer platforms such as GitHub or Jira. 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