Some data is technically necessary to be able to visit the page at all. A so-called cookie stores identifiers that make it possible to respond to your individual requests. It contains a session ID - a unique, anonymous user ID combined with an authentication identifier (user_data). A security identifier (csrf) is also stored to prevent a particular type of online attack. All of these fields are alpha-numeric, with almost no relation to your real identity. The only exception is that we monitor some requests with the IP address that you are currently using, so that we are able to detect malicious use or system defects. Additionally, a technical field is stored (singletab) to ensure that some interactions are only processed in the browser tab that is currently active. For example, a new chess game will not be opened in all your current tabs. We use your local storage to save the difference between your local clock and our server time (serverUserTimeOffset), so that we are able to display the date and time of events correctly for you. You can also enable more data fields, as described in the other sections. Your personal decision on which data storage to enable is also stored as necessary information (consent).

We offer a range of personal settings for your convenience. Options include which opponents you prefer to be paired against, your preferred chessboard and pieces, the board size, the volume setting of the video player, your preferred language, whether to show chat or chess notation, and more. You can use our web page without storing this data, but if you would like to have your individual settings remembered we recommend enabling this feature. For logged-in registered users this setting is mandatory to store information about your privacy settings, users you have blocked and your friendship settings. As a registered user we also store your data consent in these settings.

We embed a Twitter feed showing activity for the hashtag #c24live and also make it possible to share content in social networks such as Facebook, Twitter and Google+. If you enable this option social networks are able to store data in your cookies or local storage for the purpose of these features.

We would like to measure how our page is used with Google Analytics, so that we can decide which features to implement next and how to optimize our user experience. If you enable this feature Google will store your device identifiers and we will send tracking events (such as page requests) to Google Analytics. These have no direct relationship to your person except for the IP address currently being used.

To help cover the cost of free services we would like to show you advertisements from our partner networks. Members of these networks store data on the banners shown to you and try to deliver ads that are relevant. If you choose not to allow this kind of data we have to show more anonymous advertisements and will be more limited in the free services we can offer.

For registered users we store additional information such as profile data, chess games played, your chess analysis sessions, forum posts, chat and messages, your friends and blocked users, and items and subscriptions you have purchased. You can find this information in your personal profile. A free registration is not required to use this application. If you decide to contact the support team a ticket is created with information that includes your name and email address so that we can respond to your concern. This data is processed in the external service Zendesk. If you subscribe to a newsletter or are registered we would like to send you occasional updates via email. You can unsubscribe from newsletters and as a registered user you can apply several mail settings to control how your email address is used. For newsletters we transfer your email address and username to the external service MailChimp. If you buy content or subscriptions on chess24 we work with the payment service provider Adyen, which collects your payment data and processes information about the payment such as fraud protection data.