Effective date: July 1, 2026
sincere.ly ("the app," "we," "us," or "our") is operated by Mad Science Software B.V., a private limited company established in the Netherlands, and created by James Youngquist. This Privacy Policy explains what information the app collects, how we use it, and — importantly — how some of your information is shown to other people who use the app. Please read it carefully before creating an account or posting a note.
sincere.ly is currently available only to users in Costa Rica.
The most important thing to understand: sincere.ly is a location-based app. When you post a note, the note, the identity you post under, and the exact location you posted from are displayed on a map to other nearby users of the app. Other people near you will be able to see who left a note and precisely where. Do not post anything, or post from any location, that you are not comfortable sharing with strangers nearby.
1. Who We Are (Data Controller)
Mad Science Software B.V. is the data controller responsible for your personal data. You can reach us using the details in the Contact section below.
2. Information We Collect
Account information. You sign in through Firebase Authentication (a Google service). We support sign-in with email and password, with Google, and with Apple. Depending on the method you choose, we receive information such as your email address, a display name, and a unique account identifier. If you sign in with Apple and choose to hide your email, we receive an Apple-provided relay address rather than your real one. We use this information to create and secure your account.
Location data. When you create a note, the app records your exact geographic location at that moment so the note can be placed precisely on the map. We collect location only at the time you post a note; the app does not track your location continuously or in the background.
Note content. Notes are text only. We store the text you choose to put in a note. Because notes are free-form, please be aware that anything you type — including any personal or sensitive details — will be stored and shown to others as described in Section 3.
Technical and log data. When you use the app, our servers automatically record basic technical information such as your IP address, device type, app version, and the date and time of requests. We use this to operate, secure, and troubleshoot the service. We do not use Firebase Analytics, Crashlytics, or other analytics or advertising tools.
3. How Your Information Is Shown to Other Users
sincere.ly is designed to share certain information with other people. Specifically:
Your notes are visible to nearby users. When you post a note, its text and location appear on the map for other users in the vicinity to see.
Your identity is shown with your note. The name or profile you post under is displayed alongside your note, so other users can see who left it.
Your exact location is shown. The precise point where you posted is shown on the map, so other users can see exactly where a note was left.
We do not control what other users do with information they see in the app. Please use good judgment about what you share and where you share it from.
4. How We Use Your Information
We use the information we collect to:
Operate the core function of the app — creating your account and displaying notes on a map to nearby users;
Keep the app secure, stable, and functioning correctly;
Respond to your requests and support inquiries; and
Comply with our legal obligations.
5. Legal Basis and Consent
Under Costa Rica's Law No. 8968 (Ley de Protección de la Persona frente al Tratamiento de sus Datos Personales), we process your personal data on the basis of your informed, express consent, which you provide when you create an account and when you post a note that includes your location. You may withdraw your consent at any time by deleting your notes, deleting your account, or contacting us; withdrawal does not affect processing carried out before withdrawal.
Where EU data protection law (the GDPR) also applies to us as a controller established in the Netherlands, we rely on your consent and on our legitimate interest in operating the app.
6. Sharing With Service Providers
We do not sell your personal data. Aside from the display of notes to other users described in Section 3, we share personal data only with service providers who process it on our behalf so the app can function:
Google / Firebase, for account authentication;
our cloud hosting and database provider, which stores your account, notes, and location data on our behalf; and
our mapping provider, which renders the map on which notes are displayed.
These providers may only use your information to provide services to us. We may also disclose information where required by law or to protect the safety of users.
7. International Data Transfers
Some of our service providers, including Google/Firebase and our hosting provider, may process data outside Costa Rica. Where your personal data is transferred outside Costa Rica, we do so on the basis of your consent and take steps intended to keep your data protected consistently with this policy.
8. Data Retention
We keep your account information for as long as your account is active. Notes expire automatically: each note and its associated location are deleted after [specify the expiry period, e.g. 24 hours / 7 days] from posting. You can also delete a note yourself before it expires. When you delete your account, we delete or anonymize your personal data, except where we are required to retain it to comply with a legal obligation.
9. Your Rights
Under Law No. 8968, you have the rights of access, rectification, cancellation (deletion), and objection (the "ARCO" rights) with respect to your personal data.
Deleting your data and account. You can delete individual notes within the app at any time. You can also delete your entire account and associated personal data [describe in-app path, e.g. Settings → Delete Account], or by contacting us at the address below and we will process your request.
To exercise any of your rights, contact us using the details in the Contact section. If you believe your data protection rights have been violated, you may file a complaint with Costa Rica's data protection authority, PRODHAB (Agencia de Protección de Datos de los Habitantes).
If EU data protection law applies to you, you additionally have rights of restriction, portability, and the right to lodge a complaint with an EU supervisory authority.
10. Security
We use reasonable technical and organizational measures to protect your personal data, including access controls and encryption in transit. No system is completely secure, so we cannot guarantee absolute security.
11. Children's Privacy
sincere.ly is intended only for users aged 16 and older, and we do not knowingly collect personal data from anyone under 16. If you believe someone under 16 has provided us with personal data, please contact us so we can remove it. Because the app shares your identity and exact location with nearby people, we set this age threshold deliberately and encourage users to think carefully about what they share.
12. Changes to This Policy
We may update this Privacy Policy from time to time. When we do, we will revise the "Effective date" above and, where appropriate, notify you within the app. Your continued use of the app after an update constitutes acceptance of the revised policy.
13. Contact
For questions about this Privacy Policy or to exercise your rights, contact us at:
Mad Science Software B.V. Attn: James Youngquist (james@madsciencesoftware.dev)