Effective date: November 9, 2026
This Privacy Policy explains how the Hollow Chess mobile game (the “App”, formerly published as Fast Chess) handles your information. The App is provided by Galactic Toast (“we”, “us”), the data controller. If you have any questions, contact us at galactictoast.dev@gmail.com.
In short: you can play the whole game as a guest without creating an account — your profile and progress then live on your device. You may optionally sign in with a Google account, an Apple account or an email and password to sync your progress across devices, play rated online matches and appear on leaderboards; if you do, we store your progress and a small amount of account information (your email, chosen display name and a user ID) on our server. We use Google’s analytics and crash reporting to understand how the game is used and to fix bugs, and we collect gameplay statistics on our own server to tune the puzzles. When you play an online match, a match server relays your chosen display name, emoji avatar and moves to your opponent so the two of you can play in real time. When you are signed in, most of the gameplay statistics that we collect on our own server are associated with your account. The per-board records in Section 4 are not: they carry only a random installation ID.
When you create a local profile you choose a display name and a single emoji avatar. That profile, together with your game progress, ratings (Elo), streaks, solved puzzles and any custom levels you build, is stored locally on your device only while you play as a guest. We do not receive or keep this data on our servers, and it is removed when you uninstall the App. If you sign in to an account, your progress and profile are also synced to our server so they follow you to another device — see Section 3.
If Android’s automatic backup is enabled on your device, this on-device data may be backed up to your own Google Drive by the Android operating system. That backup is controlled by your device settings and your Google account, not by us.
Your choice comes first. When you first use the App, it asks whether you allow usage statistics and crash reports. Until you allow it, and whenever you decline, Google Analytics, Crashlytics crash reports and the gameplay statistics described in Section 4 are switched off. Before you answer, the App keeps a small amount of gameplay statistics (up to 128 usage counts and the records of up to 16 played puzzles) in the memory of your device only. It sends them to our server if you select Allow. It deletes them if you select No thanks or close the App. You can change your answer at any time in Settings → Share usage stats.
The App uses Google Analytics for Firebase to understand how players use the game so we can improve it. Through this service the following is collected:
The App does not collect the Advertising ID of your device. The App also turns off ad storage and ad personalization in Google Analytics.
This analytics data is processed by Google on our behalf in accordance with Google’s Privacy Policy. The iOS app sends the same data to its own Google Analytics stream.
The App also uses Google Firebase Crashlytics for crash reporting. If the App crashes, a diagnostic report is sent so we can find and fix the problem. A crash report includes the technical crash trace, the state of the device at the time (such as device model, operating-system version and available memory) and a random Crashlytics installation identifier. It does not include the contents of your games or any name you have entered. Crash reports are processed by Google on our behalf.
Our web pages. The Hollow puzzle page and the web version count visits, store button taps and solved boards as daily totals, with no cookies and nothing that identifies you; your browser’s “do not track” setting turns this off.
You can use the whole game as a guest. Even if you never sign in, the App creates an anonymous, automatically generated account identifier through Google Firebase Authentication, so that it can talk to our servers securely. It contains no personal information and is not linked to you; clearing the App’s data or uninstalling it generates a new one, disconnecting future activity from any earlier activity.
If you want to sync your progress across devices, play rated online matches and appear on leaderboards, you can create an account by signing in with Google, with Apple, or with an email address and password. Sign-in is handled by Google Firebase Authentication. When you sign in, we store:
If you sign in with Apple, Apple gives us an account identifier and, if you allow it, your name and an email address. That address can be a private relay address from Apple. We use it only for your account.
If you register with a password, that password is handled entirely by Google Firebase — we never receive or store your password. Your display name is shown publicly on leaderboards and to opponents in online matches, so please do not use personal information as your display name. To keep leaderboards fair and civil, display names are screened by an automated filter and may be removed if they violate our Terms. Signing in is optional; you can sign out at any time in Settings, and you can permanently delete your account and all associated cloud data (see Section 8).
Reports and blocks. When you report a display name or block a player, we store your account identifier, the identifier of the reported or blocked player, the name that you saw, where you saw it (a leaderboard or a match), and the time. We use this data only to review reports and to apply your blocks. We delete each report 90 days after it was made. A block stays until you undo it or delete your account. When you delete your account, we delete your reports and blocks. When there is a new report, we get a notice in a private Discord channel; the notice holds only a report number and the number of open reports, with no names or identifiers.
Hollow Pro. Google Play handles the payment; we never see your card or bank details, and we receive no order number or price. If you are signed in when you buy Hollow Pro, we store on your account that it has Hollow Pro, and since when, so the PRO badge shows beside your name to other players. On a new phone, Google Play gives your purchase back to the App. If you claim Founder Pro, we store that claim on your account in the same way. Deleting your account deletes both. If you allow usage statistics, the App also counts shop events (for example that the Pro screen was opened or a purchase was cancelled), with no order number, price or payment details.
Carve & Send. When you send a carved board, our server stores the board, how long its solution is, the board it was carved from, and the time. If you are signed in, it also stores your account, so that anyone who opens the link sees your display name with the board; the App says so before you send. A board sent without an account carries no name. A friend’s first try adds to the board’s play and solve counts, and nothing about the friend is kept. Boards are deleted one year after they are made. If you delete your account, your name is removed from your boards.
Playing an online match is optional. When you start an online duel, our match server (running on Cloudflare) connects you with another player and relays, in real time:
This information is used only to run the live match and the moves themselves are not permanently stored on our server after the match ends. If you are signed in and the match is rated, the match result and your updated rating are recorded on our server for leaderboards and so your past opponents keep an accurate game history; these records are linked to your user ID, and your display name is removed from them if you delete your account. To route your connection and to protect the service from abuse, our infrastructure provider (Cloudflare) processes your IP address; standard server logs may briefly retain connection data such as IP addresses. See Cloudflare’s Privacy Policy.
The App also periodically requests a set of daily puzzles from our server. To pick puzzles near your skill level, your current puzzle ratings are sent as part of that request; your IP address is visible to Cloudflare as with any internet request. No account or personal identifier is attached to it.
To help us tune puzzle difficulty and understand which content players enjoy, the App also sends our server gameplay statistics — for example whether a puzzle was solved or failed and how long it took (never the contents of your games). When you are signed out, these statistics are tagged with a random identifier for your app installation — either an installation ID the App generates on your device, or an anonymous account identifier automatically assigned by Firebase to your installation. Neither is linked to your name, email address or any personal detail, and you can reset both at any time by clearing the App’s data or reinstalling. When you are signed in, these statistics are instead associated with your account (user ID) so we can measure active usage and enforce fair-play limits; in that case they are linked to your account and are deleted when you delete your account (see Section 8). The per-board records below are the exception.
First-launch day. From App version 2.1.10, the gameplay statistics also include the day on which you first started the App on your installation. We use it to count new players and how many of them come back. It is kept with the same identifier as the other gameplay statistics and is deleted with them, 60 days after the day that the App sent it. We keep only totals per day (for example, how many new players came back on the next day), and these totals hold no identifier.
Per-board records. From App version 2.1.6, the gameplay statistics also include one record for each puzzle that you play. A record holds:
The App sends the three session fields only after you agree to the consent text of version 2.1.7. If you agreed before version 2.1.7, the App asks you once more, with the new text.
Each record carries the random installation ID of the App, also when you are signed in. A record never holds your name, email address, account user ID, any text that you type or your device model. We use these records to set the difficulty of the puzzles. We delete each record 90 days after the day that you played the puzzle. When you turn off Share usage stats or delete your account in the App, the App deletes the records that are still on your device and tells our server to delete all records of your installation. If your device is offline, the App tries again each time it starts, until our server confirms the deletion.
Your online rating (optional). After your first rated puzzles, the App can ask for your rating on another chess website, but only if you allow usage statistics. You do not have to answer. The App keeps only a range of 200 points (for example 1200–1399), never the number that you type. It keeps the range on your device and sends it in the per-board records. We use it to compare our puzzle ratings with other ratings (analytics), and in a later version to choose puzzles for you (personalization). You can remove it from your device at any time in Settings → Your online rating → Clear. The App then stops sending it. The records that the App made before keep it until we delete them: 90 days after the day of play, or at once when you turn off Share usage stats.
The Daily Challenge is a timed run of four puzzles, the same for every player on a given day. When you finish a run, the App sends our server your total time, the time for each puzzle, the number of misses, hints and easier puzzles you used, the difficulty division you chose, the App version, and your display name and emoji avatar. The run is linked to your account user ID, or, if you play as a guest, to the anonymous identifier described in Section 3. Runs from signed-in players appear on the public daily leaderboard with their display name, avatar and time. Guest runs are not shown on the leaderboard; if you later create an account, your guest runs are moved to it.
Daily reminder: if you turn it on, the App schedules one local notification a day on your device. It is created on your device and nothing about it is sent to us. Player alerts (optional): if you turn them on, your device’s push-notification token from Google Firebase Cloud Messaging is stored on our server together with your account user ID (or the anonymous identifier, for a guest), so we can send the alerts you asked for, for example when another player is waiting for a match. The token is removed when you turn the alerts off or delete your account. On iOS, push messages go through Apple Push Notification service and Firebase Cloud Messaging. Android and iOS ask for your permission before the App can show any notification.
We do not sell your personal data. Data is shared only with:
Hollow Chess is intended for users aged 13 and older and is not directed to children under 13. We do not ask users for their age and we do not knowingly collect personal data from, or target, children under 13. The App is not aimed at children. It is labelled for ages 13+ on Google Play and is not part of any families or children’s program on Google Play or the App Store.
Age for usage statistics. The App sends the analytics, crash reports and gameplay statistics in Sections 2 and 4 only after you select Allow. Select Allow only if you are 16 or older, or if a parent agrees. In the EU (Poland), 16 is the age at which you can give this consent yourself. From version 2.1.7, the consent question in the App says: “Allow only if you are 16 or older, or a parent agrees.”
If you are a parent or guardian and believe your child under 13 has used the App, please contact us at galactictoast.dev@gmail.com and we will delete any associated data.
Our providers (Google and Cloudflare) operate globally, so your data may be processed on servers located outside your country, including in the United States. Where required, these providers rely on appropriate safeguards for such transfers.
Data transmitted between the App and our services (including online-match connections) is encrypted in transit using industry-standard TLS/WSS encryption.
We may update this policy from time to time. Material changes will be posted on this page with an updated effective date.
Questions about this Privacy Policy or your data:
Email: galactictoast.dev@gmail.com