Privacy Policy

Last updated: 23 July 2026

1. Introduction

555 Notebook is operated from Malaysia by 0x_wzhenkai, the developer identified on our Google Play listing ("we", "our", "us"). We are the data controller for the 555 Notebook mobile application and related services (collectively, the "Service"). This Privacy Policy explains how we collect, use, store, share, and protect your personal information.

This policy provides notice of our data practices. Where applicable law requires consent for a particular activity, we will request it through the relevant feature.

2. Information We Collect

2.1 Account Information

When you register, we collect:

• Email address — used for account authentication, email verification, and password reset
• Display name — shown to other trip members
• Profile avatar (optional) — uploaded image stored securely

If you register with an email address and password, we send a one-time verification code to that address and you must confirm it before your first sign-in, so we can confirm the email belongs to you. If you sign in with Google, we receive your name, email address, and profile picture from Google (your email is treated as already verified), and we do not receive or store your Google password.

2.2 Trip and Financial Data

When you use the Service, we collect:

• Trip names, currencies, and member lists
• Receipt images and extracted data (merchant name, items, prices)
• Expense descriptions and split amounts
• Settlement records between trip members
• Activity logs within trips
• Limited product-usage events — for example, when a trip is renamed after it already contains expenses, we record which member renamed it, the old and new trip names, and the time. We use these solely to understand how the Service is used and to improve it; they are retained for up to 180 days (see Data Retention).

2.3 Device Information

We collect device tokens for push notifications (Firebase Cloud Messaging) and a coarse timezone offset (used only for "quiet hours" notification scheduling). We do not collect persistent device identifiers, advertising IDs, or location data, and we do not use third-party analytics or ad-tracking platforms (such as Google Analytics or Mixpanel). The only usage data we record is the limited product-usage events described in Section 2.2.

2.4 Purchase Information

Credit purchases are processed through Google Play Billing. We receive the purchase token to verify the purchase, then retain only a one-way SHA-256 fingerprint in the credit transaction history and a separate replay-prevention registry. The fingerprint cannot be used to recover the token. When you delete your account, we delete your credit transaction history and any raw legacy token; the registry keeps only the fingerprint, with no user or account identifier, solely to prevent the same purchase from granting credits again. We do not receive or store your payment-card or bank-account details; Google handles those details and retains its own transaction records under its policies.

2.5 Technical Information

When you use the Service, our servers automatically receive:

• IP address — used for rate limiting and abuse prevention (for example, capping account registrations per IP). IP addresses are not retained beyond what is needed for these purposes.
• HTTP request metadata — user-agent, request timestamp, and endpoint, used for operational logging and debugging.

2.6 Required and Optional Information

Your email address and display name are required to create and identify an account; without them, we cannot provide a signed-in account. An avatar is optional. Trip, receipt, expense, and settlement information is provided only when you choose to use the corresponding feature. Receipt scanning is optional — you may enter receipts and expenses manually instead. Push notifications are optional and can be disabled in the app or your device settings.

3. How We Use Your Information

We use your information to:

• Provide and maintain the Service — creating trips, processing receipts, calculating balances
• Send push notifications — settlement updates, nudge reminders, member join events
• Process receipt images — AI-powered extraction of merchant names, items, and prices
• Verify in-app purchases and manage credit balances
• Send password reset emails when requested
• Improve the Service through aggregated, anonymized usage patterns

4. Receipt Image Processing

When you upload a receipt image, it is:

1. Compressed and stored in our cloud storage (Cloudflare R2)
2. Processed by an AI vision model to extract text, items, and prices
3. Optionally translated to English if the receipt is in another language

Receipt images are accessible only to members of the trip they belong to, via time-limited signed URLs. Images are permanently deleted when the associated trip is deleted.

5. Data Storage and Security

We take the security of your data seriously:

• Encryption in transit: All data is transmitted over HTTPS (TLS)
• Password hashing: Passwords are hashed using bcrypt and never stored in plain text
• Secure token storage: Authentication tokens are stored in your device's secure storage
• Access control: Trip data is only accessible to approved trip members
• Receipt image access: Images are served via time-limited signed URLs

Your data is stored on servers that employ industry-standard security practices.

The Service is operated from Malaysia, but our service providers may process or store data in the United States and other countries where they or their infrastructure operate. Those transfers are limited to operating the Service and are subject to the providers' data-protection terms and applicable transfer safeguards.

6. Data Sharing

We do not sell, rent, or trade your personal information to third parties.

Your trip data (receipts, expenses, balances) is shared only with other approved members of the same trip. We use the following third-party processors strictly to operate the Service:

• Cloudflare R2 (Cloudflare, Inc.) — encrypted object storage for receipt images and avatars.
• Cloudflare Turnstile (Cloudflare, Inc.) — bot/abuse detection used only on our internal admin console login (not on user registration or sign-in). When an administrator signs in, their IP address is forwarded to Cloudflare during the verification challenge.
• OpenRouter and underlying AI model providers — receipt images and extracted text are routed to compatible third-party vision and language model providers to extract merchant names, line items, and prices, and to translate non-English receipts. The provider may vary based on price and availability. We do not train our own models on your receipt content; OpenRouter and each underlying provider process it under their respective data-handling terms.
• Resend — transactional email delivery for verification codes, password resets, and account notifications. Receives your email address and the message contents.
• Firebase Cloud Messaging (Google LLC) — push notification delivery. Receives your device token and the notification payload.
• Google Sign-In / Google Play Billing (Google LLC) — optional sign-in and in-app credit purchases. Verification calls are made server-to-server.
• Google Fonts (Google LLC) — supplies the Caveat and Nunito web fonts used by this website. When a page loads, your browser requests these font files from Google and necessarily sends standard request metadata such as your IP address and user-agent.
• Sentry (Functional Software, Inc.) — error and crash reporting. When the app or our servers encounter an unexpected error, we send diagnostic information — which may include your user ID, the request involved, and technical error context — to Sentry so we can diagnose and fix the problem. It is not used for advertising or behavioral tracking.
• Railway — managed cloud hosting provider for the API and database (data resides on Railway's infrastructure).
• Telegram (Telegram Messenger Inc.) — used only to send operational alerts to our team (for example, a failed receipt job or a service-health warning). These alerts contain technical context such as error codes and internal record identifiers; they do not include your name, email, or financial amounts.

Each processor only receives the data it needs to perform its function and is bound by its own privacy and data-protection terms.

7. Data Retention

• Account information: Retained while your account is active and removed or anonymized when you delete it
• Credit transaction history and purchase tokens: Account-linked history and any raw legacy token are deleted when you delete your account. A non-reversible, user-detached token fingerprint is retained for the life of the Service solely to prevent duplicate purchase grants.
• Active trips: Data is retained as long as the trip exists
• Inactive trips: Trips with no activity for 90 days may be automatically deleted
• Settled/archived trips: Automatically deleted 30 days after settlement or archival
• Demo trips: Automatically deleted after 90 days of inactivity
• Notifications: Automatically deleted after 90 days
• Failed receipts: Automatically deleted after 7 days
• Rejected settlements: Automatically deleted after 90 days
• Pending settlements: Never-confirmed pending settlements automatically deleted after 180 days
• Device tokens: Stale push notification tokens removed after 90 days of inactivity
• Product-usage events: Limited usage events (see Section 2.2) automatically deleted after 180 days
• Content reports: Reports you submit about trips, expenses, receipts, or users are automatically deleted 90 days after they are reviewed and resolved

Database backups

We retain encrypted database backups (operated by our hosting provider) for up to 30 days as part of our standard disaster-recovery practice. Backups are not used for any business purpose other than restoring service after data loss. When you delete your account, your identifying account data is removed from production immediately; any backup copy expires within 30 days. Anonymized financial records in shared trips remain as described below and are not restored with your former identity.

8. Your Rights

You have the right to:

• Access your data — view all your trip data, receipts, and expenses within the app
• Export your data — download per-trip data as CSV or PDF (Receipts/Expenses/Settlements), or your entire account as JSON via Profile → "Export my data"
• Delete your account — permanently remove your identifying account information, unused credits, credit history, and raw purchase tokens from the app settings. A non-reversible purchase-token fingerprint remains without an account link solely to prevent replay. If you own a trip with other approved members, you must first transfer ownership so their trip is not orphaned. Financial records in shared trips are preserved under "Deleted User" to maintain balance integrity for other members. See our account deletion page for details.
• Update your information — change your display name and avatar at any time

9. Children's Privacy

The Service is not intended for use by anyone under the age of 13. We do not knowingly collect personal information from children under 13. If you believe a child under 13 has provided us with personal information, please contact us so we can delete it.

10. Offline Data

The app caches trip data locally on your device for offline access. This cached data is cleared when you log out. No offline data is sent to external parties.

11. Changes to This Policy

We may update this Privacy Policy from time to time. Changes will be posted on this page with an updated "Last updated" date. Where required, we will provide additional notice or request consent before a material change takes effect.

12. Contact Us

If you have questions about this Privacy Policy or your personal data, please contact us at:

Operator: 0x_wzhenkai, Malaysia
Email: contact@notebook555.com