Software Engineer L1

Katanox; Amsterdam; On-site; EUR 42,000 - 60,000; Full time

Job summary

Katanox in Amsterdam is hiring an early-career Software Engineer for the Connectivity team. You will join a hands-on group, own small features end-to-end from your first weeks, and pair with senior engineers to grow into larger integrations.

We value solid fundamentals in data structures and algorithms, and you will work with Kotlin or Java and real third-party APIs, building reliable systems for B2B workflows and payments.

Qualifications

• Strong fundamentals: data structures and algorithms.
• Experience with APIs and typed languages (Kotlin/Java).
• Fluent English; Amsterdam-based or nearby location preferred.

Responsibilities

• Build and extend integrations with hotel systems and the Katanox marketplace.
• Ship changes to the public API used by travel buyers.
• Work with real third-party APIs, handling retries and edge cases.
• Own services in production: diagnose and fix issues, add monitoring.

Skills

Kotlin

Java

APIs

Data structures

Algorithms

Education

Bachelor's degree in CS or related

Job description

We are hiring an early-career Software Engineer for the Connectivity team in our Amsterdam hub.

About Katanox

Katanox is building the infrastructure layer for hospitality: software that connects hotels and travel buyers and moves money between them. Our platform brings distribution and payments into one workflow (contracting, connectivity, reconciliation, and settlement), so partners can operate with less fragmentation and fewer manual handoffs.

For engineers, this means building reliable systems that handle complex B2B workflows and real financial constraints, with a focus on data integrity, auditability, security, and operational excellence. We're headquartered in Amsterdam with hubs in London and New York.

About the role

You'll join the Connectivity team, which owns the Katanox marketplace end-to-end. On the supply side, hotels connect through their property management systems and channel managers. On the demand side, travel buyers integrate through our public API. In between sits the contracting flow, which decides which buyer can sell which hotel on which terms.

Availability, rates, and inventory enter the platform on one side, reservations leave on the other, and contracts in the middle decide what each buyer sees. If a rate update from a hotel is dropped, a buyer sells the wrong price. If a reservation is not delivered, a guest arrives to no room.

This is an L1 role. We expect you to arrive with solid fundamentals and real curiosity, not years of production experience. You will pair with senior engineers, own small pieces end-to-end from your first weeks, and grow into owning an integration yourself.

What you will work on

• Build and extend integrations with hotel systems: map a partner's availability, rates, and reservation models onto ours, in Kotlin, with tests and code review.
• Ship changes to the public API that travel buyers use to search and book.
• Work with real third-party APIs, with their retries, rate limits, and odd edge cases, and keep that mess out of the rest of the platform.
• Own your services in production: when a rate update or a booking fails somewhere between a hotel and a buyer, you find out why, fix it at the source, and add the monitoring that catches it next time.

What you will grow into

• Owning a whole integration or API area end to end, from design to rollout.
• The contracting flow: the rules that decide which buyer can sell which hotel on which terms.
• Keeping availability and pricing correct at scale. Millions of searches a day depend on the data your services ingest.
• Weighing in on architecture decisions with the senior engineers you pair with.

What we are looking for

• Around zero to two years of professional experience, or a strong internship and side-project record. A degree is welcome but not required.
• Solid fundamentals: data structures, algorithms, testing, and enough system design to reason about a service boundary.
• Working knowledge of Kotlin or Java, or another typed language and a clear interest in Kotlin.
• Comfort reading other people's API documentation and code, and patience for edge cases. Connectivity is a domain of exceptions.
• Curiosity about how travel distribution and payments work, and the ownership to pick up a problem rather than wait for someone else.
• Fluent in English, and based in or around Amsterdam.

How we work

A cornerstone of our culture is in-person collaboration. We follow a "hub" model with unique hubs in Amsterdam, London, and New York, where we regularly collaborate face-to-face, onboard customers and colleagues, hold design sessions, and host events.

We do not hire for strictly remote roles. We expect people to spend meaningful time in our hubs because this is how we maintain our culture, build trust, and move quickly together.

We're also a financially regulated company. That means high standards for security, auditability, and decision-making. This means your work ships with the rigor and reliability you'd expect from systems that move real money.

Our values

At Katanox, our values are the blueprint for how we work together and build our product.

• Team over the individual, no ego: We prioritize the success of the whole team over individual agendas. We win together, share credit, and leave egos at the door.
• Data beats excitement: We welcome bold ideas, but we commit based on evidence. We use data, experimentation, and clear hypotheses to decide what to build.
• Dare to do: We are proactive, take smart risks, and move from talking to doing. We learn by shipping and improve through iteration.
• See it, own it, and close it: When we spot a problem or opportunity, we take responsibility to drive it to completion instead of assuming someone else will.
• We apply radical candor: We care personally and challenge directly. We give and receive honest feedback so we can grow faster as individuals and as a team.
• In person first, call second: We prioritize in-person collaboration in our hubs to build trust, move quickly, and solve hard problems together.
• Build collaboratively: We actively involve the right people, share context early, and co-create solutions across teams and disciplines.
• Iterate fast and pragmatically: We ship small, learn quickly, and avoid over-engineering. We focus on solutions that work in reality, not just in theory.