Senior Full Stack Software Engineer

KAYAK, part of Booking Holdings (NASDAQ: BKNG), is a leading travel search engine. With billions of queries across our platforms, we help people find their perfect flight, stay, rental car, and vacation package. We are also transforming business travel with a new corporate travel solution, KAYAK for Business. As part of KAYAK, you will join a travel company operating a portfolio of global metasearch brands, including momondo, Cheapflights, and HotelsCombined. From start-up to industry leader, innovation is in our DNA, and every employee has the opportunity to make their mark. The role KAYAK is looking for a Senior Full Stack Engineer to join our SEM Experience team in Kaunas. The team builds and scales marketing experiences that help travelers discover KAYAK, including dynamic landing pages and user-journey tracking capabilities that personalize experiences and support engagement across our brands and platforms. You will work across the frontend and backend stack, partnering closely with engineers, product managers, designers, and marketing specialists. This is a hands-on senior individual contributor role with meaningful ownership of technical decisions, feature design, production reliability, and continuous improvement across the full application lifecycle. In this role, you will Design, develop, and maintain full-stack product features used by millions of travelers. Build and optimize dynamic user-facing landing pages and supporting services that personalize content based on search intent and keywords. Develop and improve APIs, backend services, and integrations that support reliable user journeys and marketing experiences. Translate product and marketing requirements into robust, scalable technical solutions. Make sound architectural decisions, evaluate trade-offs, and build prototypes where needed to validate new approaches. Review and scope feature requests, helping the team turn broad ideas into clear, actionable engineering work. Collaborate with product managers, designers, marketing specialists, and fellow engineers to deliver well-integrated experiences. Participate actively in code reviews, raising the quality bar while incorporating constructive feedback. Write and maintain unit, integration, and end-to-end tests across the frontend and backend. Troubleshoot production issues, perform root-cause analysis, and implement preventative improvements. Identify opportunities to improve performance, reliability, maintainability, and developer experience across the stack. Share knowledge, support technical discussions, and mentor less-experienced engineers through day-to-day collaboration. Please apply if you have A bachelor’s degree in Computer Science, Engineering, or a related field, or equivalent professional experience. 5+ years of professional experience building and maintaining web applications. Strong hands-on experience with frontend technologies such as TypeScript, React, Redux, and CSS, including Sass or Less. Strong hands-on experience with backend technologies such as Java and Spring. Experience working with relational databases, preferably MySQL, and writing effective SQL. A solid understanding of programming fundamentals, software design principles, and web application architecture. Experience working across multiple layers of a full-stack system, including UI, backend services, databases, and search technologies such as Elasticsearch. Experience writing and maintaining automated unit and end-to-end tests. Strong debugging, analytical, and problem-solving skills. The ability to work independently, take ownership, and collaborate effectively in a distributed, cross-functional team. Strong English communication skills, both written and verbal. Preferred qualifications Familiarity with Git and web servers such as Tomcat or Apache. Hands-on experience with CI/CD pipelines and automated testing frameworks. Exposure to Docker, Kubernetes, or other containerization technologies. Experience operating high-traffic, consumer-facing web applications. Experience with observability, production troubleshooting, and performance optimization. Experience mentoring engineers or leading technical initiatives without formal people-management responsibility. Compensation Compensation consists of three elements: Base pay: from €3,330 up to €6,660 gross per month . Significant yearly bonuses, approximately 10% of annual salary. Booking Holdings RSU (Restricted Stock Units) package worth $20,000 gross , with the possibility of receiving yearly refreshes. Benefits and perks Work from (almost) anywhere for up to 20 days per year. Funds for your career growth. Access to thousands of on-demand e-learnings. Generous additional health insurance. Flexible sick time off and additional financial support for sick leave. Additional day off on your birthday. Company-wide vacation week once a year during the winter holidays. Additional financial support during parental leave. Free lunch twice a week and daily snacks at the office. Free yoga twice a week. Paid volunteering time. No-meeting Fridays. Office and team events, including summer camp, KAYAK birthday, and winter party. Company-paid therapy sessions through SpringHealth. Company-paid Headspace subscription. Internal communities. Inclusion At KAYAK, we want everyone to have the space to grow, share ideas, and do great work. That’s why we focus on hiring the best talent from all walks of life and experiences, supporting them well, and making sure no one feels they have to fit a mold to belong here. If you need accommodations during the application or interview process, or on the job, we’re here to support you. Please reach out to your recruiter to request any accommodations. #LI-MP1