Senior Software Engineer (For Independent Contractors)

at Booking.com

📍 Amsterdam, Netherlands

EUR 60-138 per hour

SENIOR

✅ Hybrid ✅ On-site

✅ Contract / Freelance

🕙 43 hours per week

Tech Stack
Tag name is followed by "@" symbol and proficiency level value. About proficiency levels:

1-2 — basic awareness. Minimal hands-on experience, and a rudimentary understanding of the technology's purpose;

3-6 — daily use. Comfortable and regular usage, capable of handling common tasks and challenges related to the technology;

7-9 — you are an expert, you can teach others, you know all the pitfalls and tricks;

10 — exceptional knowledge, comprehensive understanding, and adeptness in all aspects of the technology, including advanced problem-solving. Think twice before claiming or demanding such level.

AI @ 4 AWS @ 4 Communication @ 7 Data Science @ 4 Experimentation Flink @ 4 GraphQL @ 4 Java @ 7 JavaScript @ 4 Kafka @ 7 Perl @ 4 Security @ 4

Details

Join the Experimentation Core team to help build and maintain the platform powering experimentation across Booking.com. The platform supports real-time metrics, experiment lifecycle management, and statistical frameworks used by engineers and data scientists.

Responsibilities

Build and own complex, high-scale systems end to end.
Develop and maintain the core experimentation platform.
Work on systems involving real-time metrics, experiment lifecycle management, and statistical frameworks.
Own services in production, including monitoring and SLIs/SLOs.
Collaborate with engineering, data science, and product stakeholders.
Maintain high standards for coding, testing, security, and production ownership.
Work at the intersection of software engineering and data science on statistically and mathematically complex products.

Requirements

Strong coding, testing, and production ownership skills.
Strong experience with asynchronous messaging and queuing systems such as Kafka or SQS.
End-to-end service ownership mindset, including monitoring and SLIs/SLOs.
Deep, hands-on experience with Java.
Solid understanding of security best practices.
Strong communication skills.
Experience collaborating with data science teams or working on data-science-adjacent products.
Strong system design judgment and the ability to thrive in ambiguous environments.