Tech Lead Full Stack Developer (f/m/x)

Sii is the leading technology consulting, digital transformation, engineering, and business services vendor in Poland. They employ more than 7,300 professionals and implement projects in various industries for clients worldwide. The company has won the Great Place to Work title 10 times in a row.

• At least 8 years of software engineering experience, including 3+ years in full-stack roles designing, building, and launching web platforms
• Strong expertise in modern frontend frameworks (React, Angular, or Vue), including component-driven architecture, state management, routing, and responsive UI
• Solid backend experience covering RESTful APIs, microservices, domain-driven design, scalable architectures, and fault tolerance
• Proven ability to build platforms and tools from scratch and deliver end-to-end solutions under tight timelines
• High level of autonomy: ownership of technical decisions, task management, and delivery with minimal supervision
• Experience with relational (PostgreSQL, MySQL) and NoSQL (MongoDB, Cassandra) databases
• Proficient with Git and version control workflows
• Deep understanding of architectural best practices combined with a fast-paced, pragmatic, and results-driven delivery mindset
• Availability to work from the Kraków office 6–8 times per month
• Fluency in English required
• Residing in Poland required

• Architect, design, and build a scalable web platform from scratch, covering both frontend and backend
• Lead development of user-facing features using modern frontend frameworks
• Develop and maintain backend services, including APIs, microservices, data models, and business logic
• Design resilient, performant architecture across databases, services, and APIs
• Collaborate closely with product, business, and engineering stakeholders in an Agile (Scrum) environment
• Ensure high-quality, rapid delivery through CI/CD pipelines, automated testing, and code reviews
• Design and build scalable cloud infrastructure, preferably on GCP, using infrastructure as code, containerization, and serverless solutions
• Mentor engineers, promote team autonomy, uphold architectural standards, and drive technical excellence
• Work with both relational and NoSQL databases

• Availability to work from the Kraków office 6–8 times per month
• Fluency in English required
• Residing in Poland required
• Sii ensures all employment decisions are based solely on qualifications and competencies and promotes equal treatment and diversity