Java Senior Software Engineer, K4B Directs

About the role

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're also transforming business travel with a new corporate travel solution, KAYAK for Business.

As an employee of KAYAK, you will be part of a travel company that operates a portfolio of global metasearch brands including momondo, Cheapflights and HotelsCombined, among others. From start-up to industry leader, innovation is in our DNA and every employee has an opportunity to make their mark. Our focus is on building the best travel search engine to make it easier for everyone to experience the world.

At KAYAK for Business (K4B), we're building the future of corporate travel technology — and the engineering teams behind it are at the heart of that mission. Our K4B engineering team in Lithuania is growing, and we're looking for a Senior Java Backend Developer to help design, build, and own our direct supplier integrations. The Direct team connects K4B straight to airlines and other travel suppliers, bringing business travelers content, fares, and services that go beyond what traditional channels offer, across search, booking, and servicing. You will help shape the team's technical direction, take on some of our hardest integration and reliability problems, and support other engineers as they grow.

This role requires working from our Vilnius office at least 3 days per week.

IN THIS ROLE YOU WILL:

- Lead the design and delivery of new direct supplier integrations, from reading partner documentation to production rollout.

- Own the quality and reliability of live integrations — monitoring them, diagnosing production issues, and handling gaps between a supplier's documentation and its real behavior.

- Evaluate the user and business value of work before committing to build, and track success metrics after release.

- Build and evolve integrations with third-party APIs (SOAP/XML, REST, and proprietary protocols), handling their quirks, rate limits, and failure modes.

- Design for suppliers that differ widely in protocols, data models, and reliability, while keeping our own model clean and consistent.

- Act as a point of contact with partners on integration issues: investigate problems, agree on solutions, and follow tickets through to resolution.

- Contribute to technical decisions: write design documents, review architecture and code, and help set standards for quality and testing.

- Support mid-level and junior engineers through code reviews, pairing, and technical guidance, and work with product, QA, and partner teams on scoping and rollout.

- Use AI coding tools as part of your day-to-day workflow — AI-assisted development is a normal part of how our team works.

PLEASE APPLY IF YOU HAVE:

- Education in Computer Science or a related field, or equivalent practical experience.