Senior Fullstack Developer

• Remote work.
• B2B Contract with 160-190 zł/h net + vat
• A role combining hands-on full stack development with genuine end-to-end product ownership.
• Opportunity to work with modern AI-assisted development approaches and turn innovative prototypes into production-ready solutions.
• A varied technical environment covering frontend, backend, cloud, databases and system integrations.
• Cooperation with an international team and both technical and non-technical stakeholders.
• A high level of independence and ownership over delivered solutions.

• Proven experience in full stack software development.
• Experience owning an application or product throughout its lifecycle – from development to deployment, maintenance, support and further evolution.
• Practical experience transforming prototypes, proof-of-concept solutions or inherited code into secure and maintainable production software.
• Ability to assess unfamiliar codebases and make pragmatic decisions about what should be retained, refactored or rebuilt.
• Frontend development experience with a component-based framework such as React.
• Very good knowledge of TypeScript, HTML and CSS.
• Backend development experience and practical knowledge of REST API design.
• Commercial experience with C# and .NET or a comparable backend technology such as Node.js.
• Experience working with relational databases such as SQL Server or Azure SQL, including writing efficient SQL queries.
• Knowledge of secure coding practices and experience identifying and remediating software vulnerabilities.
• Experience with automated testing, code review and CI/CD processes.
• Practical knowledge of Git and platforms such as Azure DevOps or GitHub.
• Experience developing and running applications in a public cloud environment, preferably Microsoft Azure.
• Familiarity with AI-assisted coding tools and the ability to evaluate, correct and harden AI-generated code.
• Ability to work independently, organise your own workload and communicate progress, risks and dependencies clearly.
• English communication skills sufficient to cooperate with technical and non-technical stakeholders.

Responsibilities

• Take end-to-end ownership of key applications, including the customer portal, covering their roadmap, development, operation, maintenance and further evolution.
• Be accountable for the availability, security, quality and technical direction of the applications you own.
• Balance the development of new functionality with reliability, maintenance and long-term product health.
• Transform rapidly developed and AI-assisted prototypes into structured, secure and supportable production applications.
• Review prototype code and decide what should be retained, refactored or rebuilt.
• Close the gap between a working proof of concept and a stable solution that can be safely operated and maintained by the wider engineering team.
• Define and maintain consistent coding, architecture and security standards.
• Write clean, maintainable and well-tested code.
• Review and strengthen application security, including dependencies, secrets management, access control and data handling.
• Identify and remediate vulnerabilities before applications are released.
• Implement automated testing, error handling, logging, monitoring and CI/CD processes.
• Ensure applications are observable, resilient and recoverable.
• Build and maintain REST APIs, integrations and automated data flows across internal and external platforms.
• Integrate applications with cloud, monitoring, ticketing, backup and recovery solutions.
• Replace manual data transfers between systems with reliable, automated processes.
• Cooperate with engineering, delivery and prototype development teams to understand the intended solution and bring it successfully into production.
• Independently plan and manage assigned work while providing clear updates on progress and potential risks.