Privacy Policy

Last updated: 2026-09-17

1. Introduction

At Hend, we take your privacy seriously. This Privacy Policy explains how we collect, use, disclose, and safeguard your information when you use our language learning application and website (collectively, the “Service”).

We prioritize data minimization and access controls to protect your privacy. Please read this Privacy Policy carefully. By using Hend, you consent to the data practices described in this policy.

2. Information We Collect

2.1 Learning Data

Hend stores learning data in Convex, our cloud database. Media files and full text bodies are stored as private objects in Cloudflare R2 and accessed through signed URLs. Learning data includes:

  • Language learning progress and spaced repetition data
  • Saved words and phrases with translations
  • Texts you have imported or generated
  • Files you upload and generated media, including images and audio
  • Reading statistics (time spent, sessions, completion)
  • Application settings and preferences

Convex processes this data to provide the Service, evaluate queries, apply access controls, and make your data available across devices. Hend does not add application-level end-to-end encryption to learning data stored in Convex or R2. See Section 4 for details.

If you use Hend’s sharing features, the content snapshot you choose to share may be accessible to anyone with the link. Disabling or deleting a share removes ordinary access through Hend. Treat shared snapshots as public information and assume that recipients may keep copies.

2.2 Account Information

When you register for an account, we process the following through Better Auth running on Convex:

  • Email address - used for account identification and authentication
  • Authentication tokens and sessions - managed by Better Auth / Convex

You may sign in with email and password or with an OAuth provider such as Google. If you use OAuth, that provider processes the information you choose to share during sign-in (typically your email address and a provider account identifier).

We do not collect your name, phone number, or other personal identifiers unless you provide them voluntarily or an OAuth provider supplies them as part of sign-in.

2.3 Payment and Credits Information

For users who purchase credits, payment information is processed by Polar, our Merchant of Record. We do not store your credit card details. We may have access to:

  • Credit balance and transaction records
  • Billing history

2.4 Usage Metering Data

To manage usage-based features (such as AI generation credits), we record usage events to our payment provider, Polar. These events include:

  • The type of action performed (e.g., text generation, translation, text-to-speech)
  • The AI model used and token counts
  • Character counts for audio generation
  • Language codes (not the content itself)
  • Cost calculations for billing

This data is associated with your customer ID for billing purposes. It does not include the content of your texts, translations, or other learning materials.

2.5 Analytics Data

With your consent, we collect analytics data to improve the Service. Analytics is opt-in - we only collect this data if you accept cookies via our consent banner. Analytics data may include:

  • Pages visited and features used
  • Error reports and performance metrics
  • Device type and browser information

When analytics is enabled, your Hend user ID (the Better Auth / Convex account identifier) and email address are used as identifiers in our analytics platform (PostHog) to associate sessions with your account.

2.6 Server Logs and Infrastructure Data

When you use the Hend application, which is hosted on Cloudflare Workers (app.hend.world), standard request metadata is collected automatically:

  • IP addresses (which may be truncated or anonymized)
  • Request URLs and response status codes
  • Performance and error metrics

3. How We Use Your Information

We use information to:

  • Provide, maintain, and improve Hend
  • Store your learning data and make it available across devices
  • Process transactions and manage your credits
  • Calculate and enforce usage limits for AI-powered features
  • Analyze usage patterns to enhance the user experience (with your consent)
  • Detect and prevent fraudulent or unauthorized activity
  • Provide customer support
  • Communicate with you about your account or credit balance

4. Data Storage and Security

4.1 Application Data Storage

Hend stores learning records, progress, vocabulary, settings, and related application data in Convex, a cloud database. Access generally requires an internet connection. Your browser or device may cache some data for performance; cached copies are not a substitute for the cloud database and may be cleared by you or the browser.

4.2 Media and Full-Text Storage

Media you upload or generate (such as images and audio) and full text bodies are stored as private objects in Cloudflare R2. Hend serves these objects through time-limited signed URLs rather than making the bucket publicly readable.

4.3 Authentication and Access Controls

Hend authenticates you with Better Auth on Convex (email/password and OAuth such as Google). Sessions and tokens are managed by Better Auth / Convex. Your Hend user identifier is used to associate learning data with your account and to apply access controls. Most learning data is limited to its creator; content you deliberately share may be readable by others.

Authorized Hend backend processes and administrators can access data when reasonably necessary for service operation, billing synchronization, support, security, migrations, and data-rights requests. We restrict that access and use it only when reasonably necessary for those purposes or when required by law.

Connections to Hend, Convex, and Cloudflare use encrypted HTTPS transport. This transport encryption does not make stored data end-to-end encrypted from Convex, Cloudflare, or Hend.

4.4 Data Retention

  • Application data in Convex is retained while your account is active.
  • Media and full-text objects in Cloudflare R2 are retained while your account is active.
  • Account information is retained by Convex / Better Auth as long as you maintain an active account.
  • Payment records are retained by Polar as required by applicable financial regulations.
  • Usage metering data is retained by Polar for billing and accounting purposes.
  • Analytics data is retained by PostHog as long as your account is active and can be deleted upon request.
  • Cached copies in your browser may remain until you clear site data or the browser removes them.

Deleting your Hend account deletes your Better Auth / Convex authentication account and initiates cleanup of associated Convex records and Cloudflare R2 objects, as well as deletion of the associated Polar customer record. We will explain any technical or legal limitation that affects a deletion request. Certain information may also be retained where required by law, for fraud prevention, to resolve disputes, or in limited backups until they are overwritten.

5. Third-Party Services

We do not sell your personal information. We rely on the following categories of third-party services to operate Hend. Each receives only the data necessary for its function.

5.1 Authentication and Application Data - Convex

Authentication is implemented with Better Auth running on Convex. Convex also stores Hend application data.

  • Data received: Email address, authentication tokens and session data, Hend user identifiers, learning records, imported and generated text metadata, vocabulary data, settings, authorship and access-control metadata, and connection metadata. If you sign in with an OAuth provider such as Google, that provider processes the information you share during sign-in.
  • Purpose: User authentication, session management, storing application data, applying access controls, and making your data available across devices
  • Data location: Convex deployments are hosted on AWS. Convex currently offers US East and EU West regions.
  • Privacy policy: convex.dev/legal/privacy

5.2 Payments - Polar

  • Data received: Email address, credit transaction data, usage metering events with metadata (action type, model, token/character counts, language codes, costs)
  • Purpose: Merchant of Record; payment processing, credit management, and usage-based billing
  • Data location: United States (via Stripe for card processing)
  • Privacy policy: polar.sh/legal/privacy

5.3 Media and Full-Text Storage - Cloudflare R2

  • Data received: Uploaded and generated media (such as images and audio), full text bodies, and object metadata needed to store and retrieve them
  • Purpose: Private object storage; objects are accessed through signed URLs
  • Data location: Cloudflare’s object-storage network; location depends on bucket configuration
  • Privacy policy: cloudflare.com/privacypolicy

5.4 Application Hosting - Cloudflare Workers

  • Data received: HTTP request metadata (IP addresses, URLs, headers), performance metrics
  • Purpose: Hosting and delivering the Hend application (app.hend.world)
  • Data location: Cloudflare’s global network
  • Privacy policy: cloudflare.com/privacypolicy

5.5 Analytics - PostHog

  • Data received: Page views, feature usage, error reports, device information. When analytics is enabled: Hend user ID (Better Auth / Convex account identifier) and email address as identifiers
  • Purpose: Product analytics and error monitoring
  • Data location: European Union (Germany) - we use PostHog’s EU-hosted instance
  • GDPR: EU-US Data Privacy Framework certified; SOC 2 compliant
  • Consent: Analytics is opt-in. Data is only collected if you accept analytics via the consent banner. You can opt out at any time by clearing your cookie preferences.
  • Privacy policy: posthog.com/privacy

5.6 AI Providers

When you use AI-powered features (text generation, translation, word explanations, etc.), your requests are processed by third-party AI providers. Here is how this works:

OpenRouter (routing layer)

  • Data received: Text prompts and generation parameters
  • Purpose: Routes AI requests to the appropriate language model provider
  • Data location: United States
  • Important: OpenRouter forwards your prompts to downstream language model providers (such as Anthropic, OpenAI, Google, and others). Each provider has its own data handling practices. OpenRouter states that it does not control downstream providers’ handling of inputs for purposes such as model training.
  • Privacy policy: openrouter.ai/privacy

5.7 Text-to-Speech - fal.ai and ElevenLabs

  • Data received: Text content to be converted to speech
  • Purpose: Generating audio pronunciation and narration
  • Data location: United States (fal.ai infrastructure); ElevenLabs processes in US, Netherlands, and Singapore
  • Important: ElevenLabs’ privacy policy states that text data may be used for model improvement unless opted out. Since Hend accesses ElevenLabs through fal.ai’s infrastructure, data passes through both providers.
  • Privacy policies: fal.ai/privacy, elevenlabs.io/privacy

5.8 Web Content Fetching - Jina AI

  • Data received: URLs you provide when importing web content
  • Purpose: Fetching and parsing web page content for import into Hend
  • Data location: Germany (EU); EU-compliant infrastructure option available
  • GDPR: GDPR compliant; SOC 2 audited
  • Privacy policy: jina.ai/legal

5.9 YouTube Data - RapidAPI

  • Data received: YouTube video URLs and video IDs
  • Purpose: Fetching video metadata and transcripts for import
  • Data location: United States (RapidAPI); the underlying API provider (yt-api) is a third-party developer hosted on RapidAPI’s marketplace
  • Privacy policy: rapidapi.com/privacy

5.10 Legal Requirements

We may disclose information if required to do so by law or in response to valid requests by public authorities (e.g., a court order or government agency).

6. Cookies and Tracking

Hend uses the following storage mechanisms:

  • Essential browser storage: Hend and its providers may use local storage and essential cookies for preferences, authentication (including Better Auth sessions), and consent. These mechanisms are necessary for the Service to function and are not used for advertising.
  • Analytics cookies (opt-in): PostHog uses first-party cookies for analytics. These are only set if you accept analytics via the consent banner.

We do not use third-party advertising cookies or tracking pixels.

7. Your Rights and Choices

Depending on your location, you may have the following rights regarding your personal information:

  • Access: Request access to the personal information we hold about you.
  • Correction: Request correction of inaccurate information.
  • Deletion: Request deletion of your account and personal information.
  • Data portability: Export your learning data (texts, saved words) via the Data tab in Settings.
  • Withdraw consent: Opt out of analytics at any time by clearing your cookie preferences.

7.1 Data Control

  • You can export your learning data at any time via Settings > Data.
  • You can delete your account through your account settings, which deletes your Better Auth / Convex account, initiates cleanup of associated Convex records and Cloudflare R2 objects, and initiates deletion of your Polar customer record. Any unused credits are forfeited upon deletion.
  • Cached copies in your browser or on other devices may remain until you clear Hend’s site data on each device.
  • We will explain any technical or legal limitation that affects a deletion request.

8. Children’s Privacy

Hend is not intended for children under 16 (or under 13 in jurisdictions where that is the applicable age). We do not knowingly collect personal information from children. If you believe we have inadvertently collected information from a child, please contact us immediately.

9. International Data Transfers

Your data may be transferred to and processed in countries other than your country of residence, including the United States. We use the following safeguards:

  • Transport security and access controls protect data while it is transmitted and restrict ordinary user access. Data stored in Convex and Cloudflare R2 is not end-to-end encrypted from the service provider.
  • Transfer safeguards depend on the provider and may include adequacy decisions, participation in the EU-US Data Privacy Framework, Standard Contractual Clauses, or another lawful mechanism.
  • Convex deployments are hosted on AWS in the region configured for Hend’s project. Cloudflare operates a global network for Workers and object storage.
  • Our analytics provider (PostHog) operates from EU-based servers (Germany).

10. California Privacy Rights (CCPA)

If you are a California resident, you have the right to:

  • Know what personal information we collect and how it is used
  • Request deletion of your personal information
  • Opt out of the sale of personal information (we do not sell personal information)
  • Not be discriminated against for exercising your rights

To exercise these rights, contact us at the address in Section 13.

11. GDPR Compliance

For users in the European Economic Area (EEA), we comply with the General Data Protection Regulation (GDPR). Our legal bases for processing are:

  • Contract performance - processing necessary to provide the Service (authentication, storing and providing your learning data, payment processing)
  • Consent - analytics data collection (opt-in via cookie banner)
  • Legitimate interests - security monitoring, fraud prevention, error tracking
  • Legal obligations - financial record keeping

You may exercise your GDPR rights (access, rectification, erasure, portability, restriction, objection) by contacting us at the address in Section 13.

12. Changes to This Privacy Policy

We may update this Privacy Policy from time to time. We will notify you of changes by:

  • Posting the updated policy and revising the “Last Updated” date
  • For significant changes, providing notice through the application or via email

13. Contact Us

If you have questions about this Privacy Policy or wish to exercise your data rights, please contact us at:

Email: oliver@gander.computer

This privacy policy aims to accurately reflect Hend’s current data practices as of the date above. We are committed to updating it as our product and third-party provider landscape evolve.