Principal Software Architect

About the role

KAYAK, part of Booking Holdings, is a travel search engine and is looking for a Principal Software Architect to define the long-term technical vision and architecture strategy for the KAYAK for Business engineering organisation. This is a senior individual contributor role with broad influence across several engineering teams, at the intersection of distributed systems, external integrations and AI-driven product experiences. At least 3 days per week must be spent in the Kaunas or Vilnius office.

Key responsibilities

• Define and own the long-term technical vision and architecture strategy for KAYAK for Business, covering search, booking, servicing, AI, identity and enterprise integrations.
• Oversee the design of reliable, scalable, secure, extensible and maintainable systems across the K4B platform.
• Lead major technical initiatives across teams, linking technical priorities to business goals.
• Lead architectural discovery: evaluate options, define boundaries and integration points, run proofs of concept and write RFCs and ADRs.
• Present architecture proposals to engineering leadership and cross-functional teams.
• Identify architectural risks, technical debt, performance and operational gaps and drive improvements.
• Establish engineering standards for reliability, observability, recoverability, security and maintainability.
• Mentor senior engineers and technical leaders through design discussions, documentation, code review and pairing.
• Contribute to cross-team alignment on shared patterns, contracts and infrastructure.

Required profile

• Proven experience designing scalable architectures for e-commerce systems.
• Track record of leading architectural design across multiple teams, producing design documents and facilitating technical reviews.
• Ability to influence technical direction across teams without direct authority.
• Experience with observability and production operations, including instrumentation, logs, metrics and incident response.
• Strong written and verbal English, able to explain complex technical concepts to technical and non-technical audiences.

Required skills

• Java or another JVM-based language, with a solid understanding of building reliable, observable and maintainable services.
• Advantage: travel technology experience (booking flows, order management, travel distribution integrations).
• Advantage: B2B integration and identity standards, service-to-service authentication and enterprise identity platforms.
• Advantage: AI or machine learning in production backends, event-driven architectures, message queues, async processing, and service-oriented monorepos.

What we offer

• Base pay of 7,000 to 10,000 EUR gross per month, plus a yearly bonus of about 10% of annual salary.
• RSUs worth 40,000 USD gross, with possible yearly refreshes.
• Work from almost anywhere up to 20 days per year, free lunch twice a week and daily snacks.
• Health insurance, flexible sick time, extra sick leave support, a day off on your birthday, a company-wide winter holiday week, paid volunteering time and no-meeting Fridays.
• Career growth funds, on-demand e-learning, yoga twice a week, paid therapy sessions and HeadSpace subscription.