Chessing Privacy Policy

Effective date: 10 October 2026

This policy explains what personal data Chessing collects, why, who receives it, how long we keep it, and your rights. It describes how Chessing works today.

Chessing collects health-related information, some of it sensitive. Please read sections 2, 4 and 5 carefully.

1. Who we are

You can reach us at chessing.support@gmail.com with any question about this policy or your data.

Chessing helps you find the patterns that link your daily habits (sleep, food, stress, social contact, screen time and more) to your chess performance.

2. What we collect

Account information

• Username, email address, date of birth, timezone, and country (inferred from your timezone).
• Chess.com or Lichess username and platform.
• A password, stored only as a bcrypt hash. We cannot read your password.
• If you are under 16: your first and last name and your parent or guardian's email address, which we need for the consent process in section 6.

Your daily log

• Sleep times and quality, and naps.
• Meals and drinks, including free-text descriptions that we use to estimate nutrition.
• Stress, mood and energy ratings, and notes about social interactions.
• Medications you list.
• Exercise, screen time before bed, and total social media time.
• Caffeine, alcohol and cigarette use.
• Work and study hours, sick days, and time spent outside home or work.
• Menstrual cycle days, if you record them.
• Custom goals you create.

Sensitive health information. Medication, mood, stress, energy and menstrual cycle information count as special category health data under the EU General Data Protection Regulation (GDPR) and similar laws. Section 4 explains where it goes.

People you add. You can add people you interact with (by name or nickname, with a category such as family or friend) and log interactions with them. Those people are not users of Chessing unless they sign up themselves. Use nicknames if you prefer.

Chess information. Your linked username, and public game data we fetch from Chess.com or Lichess: moves, results, ratings and timing. We run the Stockfish chess engine on our server to measure your accuracy.

Social and matching information. Lifestyle preferences used to suggest people with similar habits, your friends, comments you post on friends' entries, messages you send, and your blocking and privacy settings.

Puzzles and quizzes. Your best result on each puzzle, your daily puzzle results, and every move of your daily puzzle attempt, saved as you play so you can come back to it. For quizzes: the questions you were given, your answers and scores, and the quiz duels you play with friends. The puzzle on our home page can be played without an account, and nothing about it is saved.

Technical information. IP address, browser and device details, and server logs. We use these for security, rate limiting and troubleshooting. Our logs can include usernames, email addresses, and short snippets of content you submit (for example, the first part of a comment). We keep logs for a limited period (section 7).

Analytics. We use Umami, an analytics tool that we host ourselves on our own server. It records anonymous page views and feature usage. It sets no cookies, does not store your IP address, and does not identify you across visits. No third party receives this data.

Cookies. We use one strictly necessary session cookie, which keeps you logged in and protects forms against forged requests. We do not use advertising, tracking or third-party cookies.

We do not collect payment information, government identification or precise location.

3. Why we use your data

• To run your account: sign-in, email verification and password reset.
• To analyze how your habits relate to your chess performance, including the best, average and worst days comparison, ratings by level, and food, social and stress patterns.
• To generate AI-written summaries of your patterns, and to estimate nutrition from meal descriptions.
• To suggest people with similar habits, if you use the matching feature.
• To show your entries to friends according to your privacy settings, and to deliver messages and comments.
• To save your puzzle and quiz progress, and to show daily puzzle rankings and quiz duel results to you and your friends.
• To keep Chessing secure and prevent abuse.
• To comply with the law.

4. Who we share data with

We do not sell your personal data, share it with advertisers, or use it for advertising. We do not share it with data brokers.

We share data only with these providers, and only as needed for the features above:

• Anthropic (Claude AI), United States. We send parts of your data to Anthropic to generate AI summaries and nutrition estimates, and to standardize activity and food names used in matching. This currently includes free-text meal and activity descriptions, mood, stress and energy averages, summarized wellness data, medication names, menstrual cycle day counts, and social-impact results, which can include the names and nicknames of people you have added. Under Anthropic's commercial terms, Anthropic does not train its models on this data and keeps inputs and outputs for up to 30 days.
• Postmark (email delivery), United States. Delivers our account emails: verification, password reset, and notifications.
• Akamai / Linode, Milan, Italy. Hosts our servers, database and backups.
• Chess.com and Lichess. We send your linked username to fetch public game data. We do not send them your Chessing data. Their own privacy policies apply to their services.

We may disclose data when the law requires it.

What other users can see. Friends you connect with can see the entries and comments you share, according to your privacy settings. Messages are visible to the two people in the conversation. Friends can see your daily puzzle result: your number of moves, your stars and your rank among them. In a quiz duel, your opponent sees whether each of your answers was right or wrong as you play, your final score, and your win, loss and draw record against each other. If you delete your account, comments and messages you sent remain, with your name replaced (section 7).

Your consent at signup. To create an account you must tick a box confirming that you have read this policy and agree to it, and that you consent to the processing of your health-related log data, AI processing by Anthropic, and the storage and transfers described in sections 4 and 10. You can withdraw that consent at any time by deleting your account.

5. Sensitive health data

• Medication, mood, stress, energy and menstrual cycle information is used only to show you your own patterns and to generate your AI summaries.
• It is never sold, used for advertising, or shown to other users.
• It is sent to Anthropic as described in section 4.
• Data is encrypted in transit (HTTPS). Our live database and disk are encrypted at rest.

6. Age and parental approval

• Chessing is for people of any age. Sign-up asks for your date of birth. We do not verify ages. If we learn that an account belongs to a child under 13, through a report or otherwise, we will disable it and clear its identifying details.
• If you are under 16, a parent or guardian must approve your account before you can log in or enter any data. At signup we ask for their email address. We send them a consent form explaining what we collect and how it is used, including that some of it is shared with Anthropic. Until they return a signed consent form, the account cannot be used. A parent or guardian can withdraw consent at any time by emailing chessing.support@gmail.com. We then deactivate the account and clear its identifying details (username, email, name, parent details and password), as described in section 7.

7. How long we keep your data

• Active account: kept for as long as the account exists.
• Deleting your account: we clear your username, email, chess username, password, name, parent details and profile picture, and we disable the account so it cannot be logged into. Your daily log, goals, and puzzle and quiz results stay stored in our database but are no longer accessible to you or to anyone else, and you no longer appear in your friends' daily puzzle rankings. Comments and messages you sent remain visible to other users, with your name replaced.
• Backups: our servers are backed up daily, and older backups are kept for a short rolling period. Backup copies are not encrypted. Deleted data may remain in backups until they expire.
• Unverified email accounts: removed automatically if the email is not verified within 4 hours.
• Accounts awaiting parental approval: if a parent or guardian has not approved an account within 7 days of signup, the account and the details collected at signup (name, email, date of birth, parent email and chess username) are deleted automatically. Such an account cannot log in or enter any data, so it holds no daily log.
• Server logs: kept for a limited period and then rotated out. Logs may contain usernames, email addresses and short content snippets.
• Anthropic: keeps API inputs and outputs for up to 30 days under its terms.

8. Your rights

Depending on where you live, you may have these rights:

• Access and copy. Email us and we will send you a copy of the personal data we hold about you, in a readable format, within one month. You do not need a reason. We do not currently offer a self-service download.
• Correction. Most fields can be edited in your settings. For anything else, email us.
• Deletion. Delete your account in settings (section 7).
• Objection and restriction. Email us to object to a use of your data or to ask us to limit it.
• Withdraw consent. Delete your account.
• Complaints. You can complain to the data protection authority in your country.

We respond within one month and may ask you to verify your identity first.

9. Security

We use bcrypt password hashing, rate limiting on sign-in and other sensitive actions, CSRF protection on forms, HTTPS, and cookie-free analytics. No system is perfectly secure. If we discover a breach affecting your personal data, we will notify affected users and the relevant authorities as the law requires.

10. International transfers

Your data is stored on servers in Italy, in the European Union. Anthropic and Postmark are in the United States, and they receive only the data described in section 4.

11. Changes to this policy

If we make material changes, we will notify you in the app and by email before they take effect. Continuing to use Chessing after that means you accept the changes. If you do not, you can delete your account.

12. Contact

Questions, requests or complaints about your data: chessing.support@gmail.com