Senior Web Developer

Senior Web Developer
Location: Warsaw, Poland _(Hybrid – 3 days in the office, 2 days remote)_
Keystone AI is an award-winning IT and consulting company founded in Sweden, with a strong presence across Scandinavia and Europe. We partner with leading organizations to build modern, scalable digital solutions while combining strong engineering culture with long-term collaboration and business impact.
We're looking for an experienced Senior Web Developer to join our client's engineering team and help build, maintain, and enhance a modern web platform and content management systems. You'll develop new features, resolve technical issues, improve code quality, and work within the architectural standards established by the Tech Lead while collaborating closely with cross-functional teams. Using AI-assisted development tools, you'll help deliver high-quality solutions and contribute to the continuous evolution of the platform.
– Deliver new features from specification through production deployment.
– Collaborate with internal teams and external vendors on API integrations and core system connectivity.
– Investigate, troubleshoot, and resolve bugs while ensuring platform stability.
– Participate in code reviews and contribute to improving code quality.
– Write unit and integration tests and perform quality assurance on your own work as well as peer contributions.
– Utilize AI-assisted development tools to accelerate development and focus on solving complex technical challenges.
– 6+ years of professional web development experience.
– Strong expertise in Nest.js (Node.js), React, and Next.js with proven experience building integrated systems.
– Experience integrating web platforms with backend systems and external APIs.
– Experience writing testable code and participating in code review processes.
– Experience with version control systems, deployment pipelines, and deployment operations.
– Proven experience using AI-assisted development tools to improve development speed and quality.
– Fluent English.
1.  Screening Call (30 min): A short introductory conversation with our recruitment team to discuss your background, motivation, and role expectations.
2\. Cultural Fit Interview: A meeting focused on collaboration style, communication approach, and how you operate in an international environment.
3.  Technical Interview: A deeper technical discussion covering data architecture, analytics engineering, and HR data topics, including a hands-on deep dive relevant to day-to-day responsibilities.
4.  Final Interview (45 min): A concluding conversation focused on behavioural aspects, leadership and ownership mindset, and managerial alignment.