Privacy Policy
Effective date: June 29, 2026
Last updated: July 9, 2026
This Privacy Policy describes how kurozu ("we," "us," or "our") collects, uses, and shares information when you use the kurozu mobile application for iOS (the "App").
By using the App, creating a cloud account, or using cloud-connected features, you acknowledge this Policy. The App is local-first: you can build and use timelines on your device without signing in.
Contact: support@kurozu.app
1. Summary
- Local-first by default. Core timeline features work offline without an account. Data you create in local-only mode stays on your device unless you choose to copy it elsewhere.
- Cloud is opt-in. Signing in enables cloud sync and account features.
- We do not sell your data or use your timeline content to train AI models.
- Diagnostics and analytics. The iOS App uses Firebase Crashlytics for crash reporting and Firebase Analytics (Google) for privacy-conscious product analytics. These tools are configured not to receive your timeline text, health records from Apple Health, or similar sensitive content.
- Account deletion lets you request deletion of your cloud account and cloud timelines from our active systems. Local timelines on your device are not deleted by that action.
2. Scope
This Policy applies to the iOS App. It does not cover third-party websites, AI tools, or apps you paste exported text into, or services we do not operate.
The App may be distributed under a display name configured at build time (for example, "Timeline" or "kurozu"). References to "the App" mean the kurozu iOS application regardless of icon label.
3. Information you provide
3.1 Timeline and fact content
You may create timelines and facts, including titles, descriptions, tags, time expressions, and fact-type labels.
| Mode | Where it is stored | Transmitted to us |
|---|---|---|
| Local-only | On your device (SQLite) | No, unless you use cloud features or copy/export it elsewhere |
| Cloud-synced | On your device (cache) and our servers | Yes — when you create, edit, sync, or delete cloud timelines |
You choose what to enter. Content may include health-related or other sensitive information if you type it.
3.2 Account and authentication
Cloud accounts use Google Sign-In or Sign in with Apple. If you sign in, we process:
- Email address (from Google or Sign in with Apple)
- Authentication identifiers (Supabase user ID, OAuth provider metadata)
- Display name or profile information (Google or Sign in with Apple may provide your name, profile image, or related OAuth profile fields)
Sign in with Apple may provide a private relay email address. That address may represent a separate cloud account from the same person using Google Sign-In.
3.3 AI features
The initial iOS release does not enable in-app cloud AI features such as AI Add. Coming-soon labels or disabled AI controls in the App do not send your timeline content, prompts, or Apple Health data to an AI provider.
If we enable in-app cloud AI features in a future release, we will update this Policy before collecting or sharing data for those features.
3.4 Export
Export to AI builds plain text on your device and copies it to your clipboard. We do not receive export payloads on our servers.
If you choose to include selected Apple Health summaries in an export, the App shows an inline notice near that choice before copying. Once you paste exported text into another app, website, AI service, or message, that third party's terms and privacy practices apply.
3.5 Support and feedback
If you email us, we receive whatever you include in your message.
4. Information collected automatically
4.1 Crash and error reporting
We use Firebase Crashlytics to collect crash reports and technical errors, such as:
- Stack traces and error messages
- App version, build number, and OS version
- Device model and locale
- Anonymous session or crash identifiers
We configure crash reporting not to include timeline content, fact text, authentication tokens, email addresses, or Apple Health data in crash reports.
4.2 Product analytics
We use Google Firebase Analytics to understand how the App is used. Events may include, for example:
- Onboarding completion
- Authentication started / succeeded / failed (provider type only, not credentials)
- Move-to-cloud started / succeeded / failed
We do not send timeline titles, fact descriptions, health data, or email addresses to Firebase Analytics.
Firebase Analytics may collect standard device and app identifiers as described in Google's privacy documentation. We do not use the App for cross-app advertising or sell analytics data.
4.3 Network and session data
When you use cloud features, our API receives:
- Your Supabase access token (JWT) for authentication
- Request metadata (timestamps, endpoint, HTTP status, latency)
We do not intentionally log full timeline descriptions, export payloads, or complete AI prompts in server logs.
4.4 Local device data (not transmitted)
The App stores on your device:
- A device-generated local account ID (not sent to our servers)
- App preferences (for example, language choice, last-opened timeline)
- Cached cloud timelines when signed in (purged on sign-out or account deletion)
We use connectivity checks locally to show online/offline state. We do not transmit a history of your network status.
5. Apple Health (preview feature)
On supported iPhones, the App includes a preview panel that can read Apple Health data only after you grant HealthKit permission. The App may request access to:
Steps
Heart rate
Resting heart rate
Respiratory rate
Heart rate variability (HRV)
Sleep, including asleep, awake, deep sleep, light sleep, REM sleep, and in-bed intervals
Data is processed on your device to produce summary text.
HealthKit data is ephemeral and local: it is not saved to the App's database and is not uploaded to our servers or to Firebase.
The preview does not write data to Apple Health.
Selected summaries may be included in a user-directed clipboard export when you turn on the health-data export option. The App shows an inline notice that the export may contain sensitive health information and should only be pasted into services you trust.
We do not use HealthKit data for advertising, marketing, use-based data mining, or profiling.
For App Store privacy disclosures, we do not treat on-device, ephemeral HealthKit reads as data we collect, because that data is not transmitted to us.
This feature is not a medical device and is not intended to diagnose or treat any condition.
6. How we use information
We use information to:
- Provide local and cloud timeline functionality
- Authenticate you and manage your account
- Sync cloud timelines across sessions
- Process account deletion requests
- Diagnose crashes and improve stability
- Understand feature usage and improve the App
- Respond to support requests
- Comply with law and protect our rights
We do not use your timeline content to train machine-learning models.
7. How we share information
We share information only as follows:
| Recipient | Purpose | Data shared |
|---|---|---|
| Supabase | Authentication | Email, OAuth tokens/IDs, session data |
| Sign in with Google | OAuth profile data, such as email, name, profile image, and provider identifiers | |
| Apple | Sign in with Apple; HealthKit (on device) | OAuth data via Apple; health metrics stay on device unless you type them elsewhere or include selected summaries in a user-directed export |
| Our hosting provider | Cloud API and database | Cloud timelines, facts, account metadata |
| Firebase Crashlytics | Crash reporting | Technical diagnostics (no timeline content) |
| Google (Firebase) | Product analytics | Event names and non-content properties |
We may disclose information if required by law or to protect safety, rights, or property.
We do not sell personal information.
Third-party providers are expected to protect user data consistently with this Policy and applicable App Store requirements.
8. Data retention
| Data | Retention |
|---|---|
| Local-only timelines | On your device until you delete them or uninstall the App |
| Cloud timelines and facts | Until you delete them, delete your account, or we terminate the service; limited backups and operational logs may persist for a short period where necessary |
| Account record | Until you request account deletion, subject to limited records we must keep for legal, security, or operational reasons |
| Firebase Crashlytics / Analytics | Per Firebase retention settings; we configure minimal retention where possible |
9. Account deletion
You can delete your cloud account from Settings in the App.
When you confirm deletion:
- We delete your cloud timelines, facts, and related server data from active systems.
- We delete or disable your Supabase authentication user as part of that process.
- The App purges cached cloud data on your device and signs you out.
Local-only timelines on your device are not deleted by account deletion. To remove local data, delete those timelines in the App or uninstall the App.
Sign-out removes cloud data from your device cache but does not delete server-side cloud data.
If deletion fails due to a technical error, contact us at support@kurozu.app.
Some copies may remain temporarily in backups, provider logs, or fraud/security records where necessary, and are handled according to our retention settings and legal obligations.
10. Security
We use industry-standard measures including HTTPS for API traffic, authenticated access to cloud data, and separation of local and cloud account namespaces on device.
No method of transmission or storage is completely secure. You are responsible for securing access to your device.
11. Children
The App is not directed to children under 13 (or the minimum age in your jurisdiction). We do not knowingly collect personal information from children. Contact us if you believe a child has provided us information.
12. International transfers
We and our service providers may process information in countries other than where you live. Those countries may have different data-protection laws. Where required, we rely on applicable safeguards, such as adequacy decisions, standard contractual clauses, provider data-processing terms, or other lawful transfer mechanisms.
13. Your choices and rights
Depending on where you live, you may have rights to access, correct, delete, or port personal information, or to object to or restrict certain processing.
- Local data: manage directly in the App or by uninstalling.
- Cloud data: edit or delete in the App; delete your account to remove server copies.
- Analytics: iOS may offer device-level controls for analytics and tracking; the App does not use Apple's App Tracking Transparency prompt for advertising tracking.
- HealthKit: revoke permission in iOS Settings → Privacy & Security → Health.
To exercise rights or ask questions, contact support@kurozu.app.
14. Changes to this Policy
We may update this Policy. We will post the revised version at this URL and update the effective date. Material changes may be communicated in the App or by email where appropriate. Continued use after changes take effect constitutes acknowledgment.
15. Contact
kurozu
Email: support@kurozu.app
For App Store privacy nutrition labels, our practices should match the disclosures in this Policy. Third-party SDKs, including Firebase, may publish their own privacy manifests bundled with the App.