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Privacy Policy

Last updated: August 24, 2026

In short

No account, and nothing to sign up for. Fair Divider asks for no email, no phone number and no payment details. If you write to us to exercise a right, we use that email only to answer you.
Most of what we process is what you type. Participant names, the amount, the item or room descriptions and the choices made each turn, because the division cannot be computed without them. Your IP address is processed to serve the requests and kept only in short-lived security logs.
It deletes itself. Multi-device sessions are removed 7 days after they are created, the division itself is held in server memory and dropped after 24 hours of inactivity, and server logs are kept 7 days at most. If you switch analytics on, Google and Microsoft keep that data longer on their side: roughly 14 months and 90 days.
Analytics are off until you switch them on. Opt-in, never enabled by default. If you do switch them on, Microsoft Clarity replays your on-page interactions; masking keeps names, descriptions and amounts out of that recording, but it does see your approximate location from your IP. The "Cookie settings" link in the footer switches everything off again on the web; in the apps, the switch in the info menu does. The apps have no Clarity and no session replay: just the action name and the mode of use.
Your data is never sold. Our servers are in Germany and our database in the EU region; Cloudflare may route traffic through servers outside the EU under Standard Contractual Clauses, and if you switch analytics on, Google and Microsoft may process data outside the EEA. Write to [email protected] to exercise any of your rights; we answer within a month, extendable by two more for complex requests.

This summary is not the policy. The numbered sections below are what governs; where the two differ, they prevail.

1. Data Controller

Binary Spirit S.L.
Based in Spain
Contact: privacy@fairdivider.com

2. What Data We Collect

Fair Divider collects the minimum data necessary to provide the fair division service:

Participant names — entered by users when creating a division session. These may be real names or pseudonyms.
Division data — total amount to divide, item/room descriptions, choices made per turn, timestamps, and division state.
Technical data — IP addresses are processed by our server to handle REST API requests at /api/v1 but are not stored in our database beyond short-lived security logs.
Owner token — when you create a session, the server generates a random UUID called the "owner token" and returns it to your browser. The token is stored in localStorage under the key fairDivisionApiState, deletes itself 24 hours after it was last used, and is required to perform privileged operations on the session you created. It is never shared with other participants.
Local storage — we use your browser localStorage (key fairDivision_<roomId>) to enable session reconnection in multi-device mode. This data stays on your device.
Optional analytics data — only if you opt in, the website's and the apps' analytics tools process aggregate usage data and interactions. This is described in sections 7 and 14, and never occurs without your consent.

We do not collect email addresses, phone numbers, payment information or precise geolocation data, and we do not require user accounts. If you opt in to the optional analytics, an approximate country- or region-level location is derived from your IP address.

3. How We Use Your Data

Providing the service — processing division sessions, synchronizing multi-device turns, and calculating fair divisions.
Technical operation — server logging for error detection and security monitoring.
Optional analytics — if and only if you opt in, understanding aggregate usage to improve the website and the apps (see sections 7 and 14).

Legitimate interest (Art. 6.1.f) — for providing the core fair division service and maintaining server security.
Consent (Art. 6.1.a) — for the optional website analytics described in section 7 (Google Analytics 4 and Microsoft Clarity) and the optional mobile app analytics described in section 14 (Google Analytics for Firebase). These load only if you opt in, are off by default, and can be switched off again at any time. Under Article 22 of the Spanish LSSI-CE, non-essential cookies require your prior consent.

5. Data Retention

Multi-device sessions (the room, its code, the participant names, the total amount and the room descriptions) are automatically deleted after 7 days from creation.
The division itself — the rooms, the preferences entered and the resulting prices — is held in server memory, in every deployment, and deleted after 24 hours of inactivity. The database stores who is taking part in a multi-device session, the total amount and the room descriptions — not the turn-by-turn division, which stays in memory.
Server logs are retained for a maximum of 7 days.
Local storage on your device persists until you clear your browser data or the session expires.
Optional analytics data is retained by the relevant provider: approximately 14 months for Google Analytics and approximately 90 days for Microsoft Clarity (see section 7); the optional app analytics data is retained by Google for approximately 14 months (see section 14). No analytics data is collected unless you opt in.

6. Cookies and Similar Technologies

Fair Divider relies on strictly necessary cookies and equivalent storage technologies, which are exempt from prior consent under Article 22.2 of the Spanish LSSI-CE and the AEPD 2023 Cookie Guide. The website additionally offers optional analytics cookies that load only after you opt in, as described in section 7. The full inventory (strictly necessary own cookies, Cloudflare Turnstile cookies served on the multi-device page, browser-storage entries, and the optional analytics cookies set only after opt-in) is documented in our Cookie Policy.

We do not use advertising cookies, tracking pixels, or third-party cookies for profiling or behavioural advertising. The only non-essential technologies are the optional analytics described in section 7, which run solely with your consent. Cloudflare Turnstile is loaded on /multi for anti-abuse purposes only and sets no analytics or advertising cookies.

In addition to the strictly necessary technologies above, the Fair Divider website can load two optional analytics tools. The mobile app analytics is separate and is described in section 14. They are disabled by default and run only after you give explicit consent.

Google Analytics 4 — provided by Google Ireland Limited, acting as our data processor. It produces aggregate usage statistics (for example, which pages are visited and from which country). Google Analytics 4 does not store raw IP addresses.
Microsoft Clarity — provided by Microsoft Ireland Operations Limited, acting as our data processor. It produces heatmaps and session replay (a reconstruction of on-page interactions such as clicks and scrolling). Clarity masks the content of input boxes and drop-down menus in every masking mode, and we additionally apply Clarity's element-level masking to the calculator itself — the setup form, the division, the proposal and the result — so participant names, item descriptions and amounts are not uploaded to Clarity. Clarity does record the address of the page you are on, the page you arrived from, your browser and device, and an approximate location derived from your IP address. Note that names and amounts are still sent to our own servers to compute the division, as described in sections 2 and 5; the masking above concerns only what Clarity receives.

Legal basis — your consent (Art. 6.1.a GDPR; Art. 22 LSSI-CE, which requires prior opt-in for non-essential cookies). When you first use the website we ask whether to enable analytics. You can choose "Accept all" (strictly necessary + analytics) or "Essential only" (no analytics); analytics stays off unless you opt in. Your choice is stored in your browser under the fd-analytics key.

Withdrawing consent. You can change your mind at any time — withdrawing is as easy as giving consent. In the iOS and Android apps, use the "Share anonymous usage statistics" switch in the info menu. On the website, use the "Cookie settings" link in the footer of the Fair Divider app (the calculator pages) to reopen the chooser and switch analytics off; the analytics tools will no longer load.

International transfers. Google and Microsoft may process analytics data outside the European Economic Area (for example, in the United States) under the EU Standard Contractual Clauses and/or the EU-US Data Privacy Framework, in accordance with Chapter V of the GDPR.

Retention. Google Analytics data is retained for approximately 14 months; Microsoft Clarity data is retained for approximately 90 days (the providers' configured/standard retention periods).

We do not sell, rent, or share your personal data with third parties. Our infrastructure providers process data on our behalf:

Hetzner Online GmbH (Germany, EU) — server hosting
Cloudflare, Inc. (USA, with EU processing and Standard Contractual Clauses) — CDN, DNS, and DDoS protection
MongoDB, Inc. (Atlas EU region) — database hosting

If you opt in to the optional website analytics described in section 7, Google Ireland Limited (Google Analytics 4) and Microsoft Ireland Operations Limited (Microsoft Clarity) also act as data processors on our behalf. If you opt in to the optional app analytics (section 14), Google Ireland Limited likewise acts as a processor. We never sell your personal data.

9. International Transfers

Your data is primarily processed within the European Union (Hetzner Germany, MongoDB Atlas EU). Cloudflare may process traffic through global edge servers under Standard Contractual Clauses (SCCs) compliant with GDPR Chapter V.

If you opt in to optional analytics, Google and Microsoft may also process data outside the EEA (for example, in the United States) under the EU Standard Contractual Clauses and/or the EU-US Data Privacy Framework, as detailed in section 7.

You have the right to:

Access — request a copy of your data
Rectification — correct inaccurate data
Erasure — request deletion of your data (sessions auto-delete after 7 days)
Restriction — limit how we process your data
Portability — receive your data in a structured format
Objection — object to processing based on legitimate interest
Withdraw consent — withdraw your analytics consent at any time via the "Cookie settings" link in the website footer, or the "Share anonymous usage statistics" switch in the apps' info menu, without affecting the lawfulness of processing before withdrawal

To exercise any right, contact privacy@fairdivider.com with your division session code. We will respond within 30 days.

How to exercise your rights: Send an email to privacy@fairdivider.com identifying yourself. We will respond within a maximum of 1 month as required by Article 12.3 GDPR. If your request requires extraordinary complexity, we may extend this period by up to 2 additional months with prior notice.

11. Right to Complain

You have the right to lodge a complaint with the Spanish Data Protection Agency (AEPD) at www.aepd.es, or with your local supervisory authority.

12. Children

Fair Divider is not directed at children under 16 years of age. We do not knowingly collect data from children.

13. Automated Decision-Making

Fair Divider uses a mathematical optimization to calculate fair divisions. This is a mathematical computation, not profiling or automated decision-making with legal effects as defined in GDPR Art. 22.

14. Mobile Apps

The Fair Divider apps for iOS and Android use the same /api/v1 backend described in this policy, with the same purposes, the same retention periods and the same rights.

Optional analytics in the apps. The apps include optional analytics based on Google Analytics for Firebase. It ships switched off: no event is sent and no usage data is collected until you turn on the "Share anonymous usage statistics" switch in the app's info menu. Turning it back off stops collection that same instant.

What is sent if you turn it on. The name of five actions (starting a division, completing it, creating a shared division, joining a shared division and sharing a result) and one additional field: the mode of use, that is, whether you are using the app on a single device or across several. In addition, Firebase generates its own identifier for the app installation on your device and collects standard device and usage data, such as the model, system version, language and an approximate country-level location derived from your IP address.

What is never sent. Participant names, room or item descriptions and amounts never leave the app for analytics, under any circumstances. The device advertising identifier is not used either: on Android we explicitly remove that permission from the app. We show no ads, build no profiles and do not track you across apps or websites.

Legal basis: your consent (art. 6(1)(a) GDPR), given when you turn the switch on and withdrawn when you turn it off. Withdrawing is as easy as giving it and does not affect the lawfulness of processing carried out before withdrawal.

Processor, destination and retention. The data is processed by Google Ireland Limited on our behalf, in the same Google Analytics 4 property used by the website, and is retained for approximately 14 months. Google may process it outside the European Economic Area under the conditions in section 9. Your rights and how to exercise them are those of sections 10 and 11.

The apps do not include Microsoft Clarity or any advertising SDK, and do not request device permissions beyond what is strictly required for the user-initiated action (for example, sharing a division link). Diagnostic data sent by the operating system to its respective app store (Apple App Analytics, Google Play Console) is governed by the privacy policies of Apple and Google respectively, and not by Binary Spirit S.L.

15. Account & Data Deletion

Fair Divider does not require a user account. Multi-device sessions auto-expire 7 days after they are created, and the division itself is dropped from server memory after 24 hours of inactivity. To delete your data sooner, or to remove all locally stored data on your device, see our dedicated Account & Data Deletion page.

16. Changes to This Policy

We may update this Privacy Policy from time to time. Changes will be posted on this page with an updated date.

24 August 2026 → 28 August 2026: the iOS and Android apps now include optional analytics (Google Analytics for Firebase), off by default and switched on from the info menu. Section 14 previously stated that the apps carried no analytics; it has been rewritten with the detail of what is and is not collected. Sections 2, 3, 4, 5, 7, 8 and 10 have been corrected to distinguish the website analytics from the app analytics.

20 August 2026 → 24 August 2026: sections 3, 5 and 15 corrected and one retention period extended. The division held in server memory now expires after 24 hours of inactivity instead of 2, so that a division survives being left overnight. The same sections previously described that memory store as applying only to deployments without a database, which was wrong: it applies to every deployment. Section 3 also corrected the owner token, which is stored in localStorage with a 24-hour self-expiry and not in sessionStorage.

27 June 2026 → 8 August 2026: section 7 corrected. The Microsoft Clarity masking mode was described as Strict; it was Balanced. Element-level masking has been applied to the calculator surfaces, and shared-result links no longer carry participant names in the address bar.

17. Contact

For privacy-related inquiries: privacy@fairdivider.com