Java Senior Software Engineer, K4B Directs

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.

Significant hands-on experience with Java, including designing and operating production backend systems.

Strong experience with the Spring framework and SQL databases.

Experience integrating with third-party systems and working directly with their providers on communication, troubleshooting, and ticket escalation.

Experience onboarding new partners or suppliers onto an existing platform.

A track record of leading projects end to end and supporting the growth of other engineers.

Fluent English communication skills.

Comfort working in a hybrid model, with at least three office days per week.

Bonus skills:

Experience with airline direct-connect or NDC APIs.

Knowledge of the travel domain: fares, offers and orders, ancillaries, ticketing.

Experience with API certification or supplier testing programs.

Familiarity with AI coding tools and interest in using them to accelerate development.

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

Additional financial support for your sick leave

Additional day off on your birthday

Company-wide vacation week once a year (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 such as summer camp, KAYAK birthday, winter party and more!

Company-paid therapy sessions through SpringHealth

Company-paid subscription to HeadSpace

Internal Communities

Compensation

Senior Java Backend Developer salary consists of three elements:

Base pay: from 3330 EUR up to 6660 EUR gross monthly.

In addition:

Significant yearly bonuses, approx 10 percent of annual salary

Booking Holdings RSU (Restricted Stock Units) package, worth [amount] gross, with possibility to receive yearly refreshes

Inclusion

At KAYAK, we want everyone to have the space to grow, share ideas and do great work. That's why we're focused on hiring the best talent from all walks of life and experiences, supporting them well and making sure no one feels like they have to fit a mold to belong here.

Need any adjustments for the interview, application or on the job? No problem - just give us a heads-up. We've got you.

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