ACM RecSys Challenge 2019


The RecSys Challenge 2019 will be organized by trivago, TU Wien, Politecnico di Milano, and Karlsruhe Institute of Technology. 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. trivago has established 55 localized platforms in over 190 countries and provides access to over two million hotels, including alternative accommodations, with prices and availability from over 400+ booking sites and hotel chains.

This year’s challenge focuses on travel metasearch. The goal of this challenge is to develop a session-based and context-aware recommender system using various input data to provide a list of accommodations that will match the needs of the user.

In the challenge, participants will be tasked with predicting which accommodations (items) have been clicked in the search result during the last part of a user session in an offline evaluation setup. To this end, trivago will release a public dataset of hotel search sessions.

A detailed description of the challenge will be made available soon (see tentative timeline).


Peter Knees, Yashar Deldjoo, Farshad Bakhshandegan Moghaddam, Jens Adamczak, Gerard-Paul Leyson, and Philipp Monreal. 2019. "RecSys Challenge 2019: Session-based Hotel Recommendations." In Thirteenth ACM Conference on Recommender Systems (RecSys ’19), September 16–20, 2019, Copenhagen, Denmark. 2 pages. https://doi.org/10.1145/3298689.3346974, BibTex

Jens Adamczak, Gerard-Paul Leyson, Peter Knees, Yashar Deldjoo, Farshad Bakhshandegan Moghaddam, Julia Neidhardt, Wolfgang Wörndl, and Philipp Monreal. 2019. "Session-Based Hotel Recommendations: Challenges and Future Directions." arXiv:1908.00071, BibTex

Participation and Data

The data for this year's challenge is provided by trivago and can be downloaded from https://recsys.trivago.cloud/. You can access the data once you create an account and agree with the terms and conditions. The information on the challenge participation can also be found on this website.

Timeline top

Note: the timeline is subject to slight modifications.

When? What?
March 2019 Dataset Release & RecSys Challenge starts The website will go live on March 05.
June 30, 2019 RecSys Challenge ends
Final submission due (11:59 PM in the UTC-12:00 time zone).
July 2019 Announcement of the final leaderboard and winners
Paper submission for RecSys Challenge Workshop
July 22, 2019 Paper submission due
23:59, AoE (Anywhere on Earth)
See paper submission guidelines
August 01, 2019 Paper Acceptance Notifications
August 14, 2019 Camera-ready due for the accepted papers.
Extended to August 28, 2019
September 16-20, 2019 Workshop will take place as part of the ACM RecSys conference in Copenhagen, Denmark.

Paper Submission Guidelines top

The workshop will feature presentations of accepted contributions to the RecSys Challenge 2019 organized by trivago, TU Wien, Polytechnic University of Bari, and Karlsruhe Institute of Technology. In the challenge, which originates from the domain of online travel recommender systems, participants have to build a click-prediction model based on user session interactions. All submissions presented in the workshop will have gone through a thorough paper review process and describe the best performing or otherwise notable approaches submitted to the challenge.

Link to the workshop website:

Program Committee top

Challenge Organizers top

Advisors top