RecSys 2019 Overview


trivago is a global hotel search platform focused on reshaping the way travelers search for and compare hotels, while enabling advertisers of hotels to grow their businesses by providing access to a broad audience of travelers via our websites and apps. We provide aggregated information about the characteristics of each accommodation to help travelers to make an informed decision and find their ideal place to stay. Once a choice is made, the users get redirected to the selected booking site to complete the booking.

It’s in the interest of the traveler, advertising booking site, and trivago to suggest suitable accommodations that fit the needs of the traveler best to increase the chance of a redirect (click­out) to a booking site. We face a few challenges when it comes to recommending the best options for our visitors, so it’s important to effectively make use of the explicit and implicit user signals within a session (clicks, search refinement, filter usage) to detect the users’ intent as quickly as possible and to update the recommendations to tailor the result list to these needs.


The best five teams will be rewarded with the following prizes:

Winner: 8.000 Euro
Second: 4.000 Euro
Third: 2.000 Euro
Fourth: 1.000 Euro
Fifth: 1.000 Euro

The Challenge

We’ve partnered with researchers from TU Wien, Politecnico di Milano, and Karlsruhe Institute of Technology to launch the RecSys Challenge 2019, the annual data science challenge for the ACM Recommender Systems conference, to give developers, data scientists and anyone who’s interested the chance to work on real-world data science problems and large data sets. This year's challenge is to develop a session-based and context-aware recommender system to adapt a list of accommodations according to the needs of the user. In the challenge, participants will have to predict which accommodations have been clicked in the search result during the last part of a user session. Afterwards predictions are evaluated offline and scores will be displayed in a leaderboard. To this end, we have released a public dataset of hotel search sessions. Register here to download the dataset and start the challenge!

More information

More information about the challenge details regarding evaluation, metrics, submission format, etc. can be found on the dataset page and you will find all you need to know about the challenge timeline, workshop, paper submission and selection on the official RecSys Challenge website.

Details about partcipation

License agreement/Terms and conditions

You can only participate in the challenge and download the Dataset if you accept the Terms and Conditions.


Challenge Organisers


Behind the scenes @ trivago

Join the trivago RecSys Challenge 2019

Register now!

trivago techblog

With employees from all over the world, trivago is an international IT company operating on a very large scale. Our goal is to provide the best hotel search possible. This blog is the ideal place to talk about our ideas, our prototypes and our tech stack which make our vision become reality. We love to collaborate and communicate so please be invited to contact us and comment on our posts.

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We are hiring!

Tackling hard problems is like going on an adventure. Solving a technical challenge feels like finding a hidden treasure. Want to go treasure hunting with us?

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Need help?

Check out the RecSys Challenge Google Forum or get in touch by mail via