Privacy Policy for Schuldnix

1. Introduction

Welcome to Schuldnix, a service of Lutec Solutions GmbH. This privacy policy explains how we collect, use and protect your personal data when you use our Schuldnix service.

2. Controller

3. Personal data we collect

When you use Schuldnix, we collect the following types of personal data:

• Account information: email address, name, optional display name, password hash and user settings.
• Sign-in with Google (optional): If you sign up or sign in via “Continue with Google”, you are redirected to Google Ireland Limited (Gordon House, Barrow Street, Dublin 4, Ireland). With your consent, Google sends us your name, your email address, whether it is verified, your profile picture and a Google account ID. We use this data solely to create your account and sign you in (Art. 6(1)(b) GDPR). We do not take over your Google profile picture automatically: only if you choose “Use Google profile picture” in your profile do we download it from Google once and store it as your profile picture with us. We do not access your Google account beyond this. Google is responsible for the processing during sign-in itself; this may involve a transfer to Google LLC in the USA, which is certified under the EU-U.S. Data Privacy Framework. For details, see Google’s privacy policy. You can still sign up and sign in with an email address and password without Google.
• User-generated content: information about expenses, groups, group memberships and settlements that you create in our service. This includes in particular comments on expenses and optional notes on settlement payments, which you can enter as free text. These free-text fields may contain personal data if you choose to enter it there.
• Images: optionally uploaded profile pictures and group cover images that you can use to personalise your account and your groups. If you choose a group cover image via the built-in image picker (based on Unsplash), the selected image is downloaded by our servers and stored on our own infrastructure. Your device does not connect to Unsplash directly, and no personal data is sent to Unsplash.
• Uploaded files: users can upload images and files, for example photos of receipts for expenses. These uploads may contain personal data (e.g. names, addresses or payment details on receipts). A receipt photo is only analysed automatically if you explicitly choose "Scan receipt" while adding an expense (see section 6, Berget AI).
• Usage data: information about how you interact with our service, including access times, pages viewed and features used.
• Device information: information about the device you use to access our service, including device type, device model, operating system (including version), browser type and language setting.
• IP address and session data: when you sign in and during active sessions, we store your IP address and technical session information (user agent, time of sign-in). This data is used for authentication, to secure your account and to detect and prevent abuse.
• Push notification tokens (mobile app): if you allow the mobile app to send push notifications, we store the device token issued by the operating system as well as the platform (iOS/Android), device model, operating system version, language setting and time of last use. This data is needed to deliver notifications to your device and is removed when the device signs out or when you delete your account. Depending on the type, push notifications may contain information such as group names, names of other group members, expense descriptions or amounts. You can turn off push notifications at any time in your operating system’s settings.
• Camera and photo access (mobile app): at your request, the mobile app can access your device’s camera or photo library, e.g. so you can take or choose receipt photos or profile pictures. Access only happens after you explicitly grant it through your operating system’s permission system. Only the images you actively select are sent to our service; there is no automatic or hidden access to your photo library.
• Feedback: if you send us feedback via the in-app feedback feature, we store the message you enter, an optional rating (1–5) and the chosen category, together with your user ID and the time of submission. The message may contain personal data if you choose to include it.
• Cookies: we only use technically necessary first-party cookies – for authentication and session management, and one cookie to measure how you found us. We do not set third-party cookies or cookies that recognise you across other websites (see also section 10).

4. Purposes and legal basis of processing

We process your personal data for the following purposes and on the following legal bases:

5. Retention period

We only keep your personal data for as long as necessary for the purposes for which it was collected, or as required by applicable laws and regulations:

• Account information: we keep this information for as long as you have an account with us. If you delete your account, your personal identifiers (name, email address, display name, profile picture) are deleted immediately, without a waiting period. Your user profile is replaced by a technical placeholder in the form “Former member #xxxx”. We do not store any separate link between this placeholder and your original email address or name. In individual cases, however, other group members may be able to identify you from the context of earlier shared expenses. Active sessions, sign-in credentials (password) and registered push device tokens are also removed immediately; signing in to this account again is not possible. The original email address is released and can be used to register again.
• Expense and group data: we store this data for as long as you have an account with us, unless you delete it manually. Please note:
  • If you leave a group, this ends your future participation in that group. Expense, share and settlement data that already exists (including expenses you paid and shares allocated to you) remains part of the shared group history for the other group members, insofar as this is necessary to keep the accounts traceable and to protect the legitimate interests of the other group members.
  • If you delete your entire account, we delete your direct identifiers such as name, email address, display name and profile picture immediately, without a waiting period. Where you took part in shared groups, expenses or settlements, the historical accounting data needed for them is kept and assigned to your replaced user profile (“Former member #xxxx”, see “Account information” above). This keeps shared accounts traceable, preserves the integrity of the group history and, where applicable, serves the establishment, exercise or defence of legal claims. The legal basis is Art. 6(1)(f) GDPR; the right to erasure may be restricted under Art. 17(3) GDPR. Your own comments on expenses are deleted when you delete your account.
• Images: profile pictures and group cover images are stored for as long as you have an account with us. When an image is updated or removed, the previous image is deleted. After account deletion, all associated images are deleted.
• Uploaded files: files uploaded to expenses (e.g. receipt photos) are stored for as long as the associated expense exists. When the expense or the account is deleted, the associated files are deleted as well.
• Session data (IP address, user agent): active sessions expire automatically after 30 days. Expired session records are deleted from our database by a regularly scheduled clean-up job.
• Push notification tokens: these are deleted as soon as you sign out on a device or uninstall the mobile app. Devices without activity (no access for more than 90 days) are also removed automatically.
• Feedback: feedback submitted via the in-app feedback feature (message, rating, category) is kept until your feedback has been fully dealt with, but no longer than 24 months after receipt. When you delete your account, associated feedback entries are deleted as well.
• Server access logs: technical access logs of our servers (e.g. IP address, time, requested resource) are kept for a maximum of 14 days to keep the service running and to fend off attacks, and are then deleted.
• Usage statistics (Umami): we store aggregated statistics from our self-hosted Umami instance (page views, referrers, browser and device type) in aggregated form. IP addresses are not stored permanently and are not used to recognise individual users. For details, see section 10.

6. Recipients and transfers

We may share your personal data with the following categories of recipients:

• Service providers: we use third-party providers to support our service:
  • Hetzner Online GmbH (server hosting and object/image storage in Germany via Hetzner Object Storage) – Privacy policy
  • Brevo GmbH (Köpenicker Str. 126, 10179 Berlin, Germany) – sending transactional emails (e.g. email verification, password reset). This involves in particular your email address and the content of the email. – Privacy policy
  • Berget AI AB (Stockholm, Sweden) – AI inference service for automatic category suggestions. When you enter a description while adding an expense, only our server (not your device) sends that description and the name of the selected group to the Berget AI API (api.berget.ai) to suggest a matching category (e.g. "Groceries", "Accommodation") and to detect whether the expense is only for a person named in the description (e.g. "Dinner for Anna"). For this, neither your IP address nor your name, email address, amounts, group members or receipts are sent. Personal data is only included if you write it into the description yourself. If you also choose "Scan receipt", our server sends the selected photo (reduced to at most 1600 pixels in your browser) and the group's currency to Berget AI to read the receipt's title, amount, currency and date and prefill the form with them. The photo may contain anything printed on the receipt, e.g. the shop, items bought, the time or parts of a card number. We do not store the photo for this step; it is only uploaded as an ordinary receipt when you save the expense, unless you remove it first. Processing takes place within the European Economic Area. The legal basis is Art. 6(1)(f) GDPR; our legitimate interest is faster and more consistent expense entry. The suggestion is non-binding and you can change it at any time. – Privacy policy
  • Unsplash Inc. (USA) – when you search for a group cover image via the built-in image picker, only our server (not your device) sends the search term you entered to the Unsplash API (api.unsplash.com). Neither your IP address nor account or device data is sent to Unsplash. The selected image is then downloaded by our server and served from our own infrastructure. The legal basis is Art. 6(1)(b) GDPR, insofar as the image search is necessary to provide the group image feature you requested, and additionally Art. 6(1)(f) GDPR based on our interest in providing external image content securely via our server. The search term is transferred to the USA on the basis of standard contractual clauses (Art. 46(2)(c) GDPR). – Privacy policy
  • AYR Tech (Pty) Ltd (South Africa) – ExchangeRate-API exchange rate service. When you record an expense in a currency other than the group currency, only our server (not your device) fetches current exchange rates from ExchangeRate-API for the currency code in question (e.g. “USD”, “CHF”). When using ExchangeRate-API, we do not send any personal data, only technical currency information such as the currency code. In particular, neither your IP address, account or device data nor names, receipts, amounts, expense descriptions or any other user content are sent. Your device does not connect to ExchangeRate-API directly. – Terms of use
  • Apple Inc. (USA) – Apple Push Notification service (APNs) for delivering push notifications to iOS devices, and distribution of the mobile app via the Apple App Store. To deliver notifications, device tokens and notification content are sent to Apple. The transfer to the USA is based on standard contractual clauses (Art. 46(2)(c) GDPR). – Privacy policy
  • Google LLC / Google Ireland Ltd. – Firebase Cloud Messaging (FCM) for delivering push notifications to Android devices, and distribution of the mobile app via the Google Play Store. To deliver notifications, device tokens and notification content are sent to Google. Where data is transferred to the USA in the process, the transfer is based on standard contractual clauses (Art. 46(2)(c) GDPR). – Privacy policy
• App stores: when you download or update our mobile app from the Apple App Store or Google Play Store, the respective operators (Apple Inc. or Google LLC/Google Ireland Ltd.) process data on their own responsibility (e.g. Apple ID/Google account, device information, download history). We have no influence over this processing; it is subject to the respective provider’s privacy terms.
• Legal requirements: we may disclose your personal data if required by law or where necessary in response to lawful requests from public authorities.

7. Data processing on our behalf (Art. 28 GDPR)

Where service providers process personal data on our behalf and solely on our instructions, we conclude data processing agreements with them in accordance with Art. 28 GDPR. These agreements ensure that the providers have taken appropriate technical and organisational measures to protect your data and process it only within the scope of our instructions.

In particular, we have data processing agreements with the following providers:

• Hetzner Online GmbH – server hosting and object storage in Germany.
• Brevo GmbH (Köpenicker Str. 126, 10179 Berlin, Germany) – sending transactional emails.
• Berget AI AB (Stockholm, Sweden) – AI inference for automatic expense category suggestions and reading scanned receipts.

We also use services whose providers (e.g. Apple, Google, Unsplash) act in part as independent controllers (Art. 4(7) GDPR) for their push, store or API functions. Where providers in the USA are certified under the EU-U.S. Data Privacy Framework, we base the transfer on the corresponding adequacy decision of the European Commission (Art. 45 GDPR). Otherwise, we base the transfer on standard contractual clauses in accordance with Art. 46(2)(c) GDPR, supplemented by additional safeguards where necessary. We will gladly provide you with a copy of these safeguards on request.

8. Your rights

Under the GDPR, you have the following rights:

• Right of access: you have the right to request information about the personal data we process about you.
• Right to rectification: you have the right to request the correction of inaccurate personal data.
• Right to erasure: you have the right, under certain circumstances, to request the deletion of your personal data. Please note that this right may be restricted under Art. 17(3) GDPR, for example for the establishment, exercise or defence of legal claims. In shared group contexts, we therefore anonymise your record to a pseudonym instead of deleting the other members’ expense history. For details, see section 5.
• Right to restriction of processing: you have the right, under certain circumstances, to request that the processing of your personal data be restricted.
• Right to data portability: you have the right to receive your personal data in a structured, commonly used and machine-readable format.
• Right to object: you have the right to object to the processing of your personal data based on legitimate interest.
• Right to withdraw consent: where processing is based on consent, you have the right to withdraw it at any time.

To exercise any of these rights, please contact us at legal@lutec-solutions.com.

9. Data security

We use appropriate technical and organisational measures to protect your personal data against accidental or unlawful destruction, loss, alteration, unauthorised disclosure or unauthorised access.

10. Cookies and tracking technologies

Our service only uses technically necessary first-party cookies: for authentication and session management, and for the source measurement described below. You can control cookies through your browser settings.

For web analytics, we use a self-hosted Umami instance on our servers in Germany. Umami does not use cookies and does not create cross-user profiles. We collect aggregated usage statistics, in particular page views, referrers, browser and device type, and approximate technical usage information. IP addresses are not stored permanently and are not used to recognise individual users. No data is passed on to third parties. The analysis serves solely to improve our service technically and in terms of content. The legal basis is Art. 6(1)(f) GDPR. Umami respects “Do Not Track” settings. In addition, we count individual steps as events without personal reference, such as “calculator result shown”, “sign-up started”, “sign-up completed” or “sign-up failed” (with the error type, without inputs such as name, email address or amounts).

If you choose “Save as group” in a calculator, we store the names and amounts you entered in your browser’s local storage (localStorage) so they survive signing in. They are only sent to us once you confirm “Create group” while signed in, and are then deleted from the browser. Unconfirmed entries are no longer taken over after seven days; you can delete them at any time with “Discard” or via your browser data. The legal basis is Art. 6(1)(b) GDPR (use of the service initiated by you).

On your first visit to a public page, we also set a technically necessary first-party cookie (“sx_src”, httpOnly, SameSite=Lax, valid for 30 days). It stores only the host of the referring website (without path or parameters), the path of the page visited (without parameters, except “utm_source”, “utm_medium” and “utm_campaign”) and a timestamp. No IP addresses, browser identifiers or device information are stored, no third-party cookies are set and no data is passed on to third parties. If you register an account, this information is stored once with your account (fields: channel, referrer host, landing path, utm_source) and the cookie is deleted. The sole purpose is to measure how people find our service; the legal basis is Art. 6(1)(f) GDPR. When you delete your account, these fields are removed together with your other personal data.

11. Automated decision-making and profiling

We do not use automated decision-making, including profiling, within the meaning of Art. 22 GDPR.

The automatic expense suggestions (see section 6) only assign a description to a category, propose who an expense is for, or prefill fields from a scanned receipt. They have no legal or similarly significant effect on you, change neither amounts nor balances on their own, and you can change them at any time.

12. Whether you are required to provide personal data

Providing certain data, in particular your email address, password and the details needed for groups, expenses and settlement calculations, is required to use the Schuldnix service. There is no contractual or legal obligation to provide this data; without it, however, we cannot provide the service, or only to a limited extent.

Optional details – such as profile pictures, display names, comments, notes on settlement payments, receipt uploads, group cover images or feedback – are voluntary. If you do not provide this data, some convenience or personalisation features cannot be used; the core features generally remain available.

13. Changes to this privacy policy

We may update this privacy policy from time to time. We will inform you of changes by publishing the new privacy policy on this page and updating the date of the last update.

14. Contact

If you have any questions or concerns about this privacy policy or our data practices, please contact us at:

15. Complaints

You have the right to lodge a complaint with a data protection supervisory authority, in particular in the Member State of your habitual residence, your place of work or the place of the alleged infringement.

The supervisory authority responsible for us is: