Privacy Policy

1. Content and automatic saving

Klars explains words and text to support language learning. Content includes text you type or paste, text you select in another app and send to Klars through the translation extension, and words used for requested practice text.

• Successful word lookups are automatically saved to Words. A word already in Dictionary is restored to Words without creating a duplicate, preserving its familiarity stage.
• Successful sentence and text lookups are automatically saved to Sentences, including lookups completed in the extension.
• Saved records include the original content, generated explanations, learning and review progress, identifiers, and timestamps. The app and extension use shared storage so results are available in the main app.
• Failed, incomplete, or cancelled lookups do not save partial definitions as completed results.

2. Online AI processing

Online explanations, translations, word insights, and practice-text generation send the content needed for the request through Cloudflare infrastructure and OpenRouter to an AI hosting provider. This can include selected text from another app, words chosen for practice, and a previous generated answer when needed to correct an invalid result.

The current primary model is OpenAI GPT-5.6 Luna, with DeepSeek V4 Flash as a fallback when the primary route is unavailable or a response needs recovery. Model developers and hosting providers can be different companies. Current hosting routes include Microsoft Azure and Relace; OpenRouter selects eligible routes dynamically, so the hosting provider can change.

Our requests require OpenRouter routes that prohibit provider data collection for training and are classified as zero data retention. These controls concern AI inference content. They do not eliminate operational or billing metadata, and OpenRouter permits temporary in-memory prompt caching under its zero-retention rules.

Klars instructs Cloudflare AI Gateway to omit request and response bodies from its logs and to bypass response caching. Request metadata can still be logged. OpenRouter and the selected hosting provider process requests under their own applicable policies; the model name alone does not identify the company receiving the text.

Read the OpenRouter privacy policy, routing and retention rules, and provider directory. Hosting policies include Microsoft Azure and Relace.

3. Pronunciation and audio

Online pronunciation sends the text to be spoken and its language to Cloudflare Workers AI, which runs the MeloTTS speech model. Generated audio is cached on your device to reduce repeated downloads.

For Pro users, Online pronunciation is the default. Opening a word lookup or viewing the current Words card can automatically preload audio before you press the speaker button. This also applies to word lookups in the translation extension. Preloading does not start playback.

Select Local in pronunciation settings to use device speech voices and stop new requests to Klars' online speech service. See Cloudflare's Workers AI data policy, which states that customer content is not used for model training without explicit consent.

4. Device storage and iCloud

Klars stores your library and learning progress on your device. When iCloud Sync is on, Apple's CloudKit also processes saved content, explanations, progress, and deletion records to sync supported data across your devices using the same Apple Account.

iCloud Sync is optional and can be changed in Settings. It defaults on for eligible Pro users unless they have changed that preference. Turning sync off does not itself delete copies already stored in iCloud or on another device. Apple handles iCloud data under its privacy policy.

5. Purchases and subscriptions

Apple processes App Store payments. Klars uses RevenueCat to validate purchases, restore access, and manage subscription status. This involves an app user identifier, purchase receipts or transaction information, product and entitlement status, and associated app and device information. We do not receive your full payment-card details. See Apple's App Store privacy information and RevenueCat's privacy policy.

6. Service operation and support

Hosting and service providers process network and request information to deliver the service, measure usage, diagnose failures, and prevent abuse. Depending on the service, this includes IP addresses, browser or app information, request identifiers, timestamps, model and provider names, token counts, costs, response status, and duration. Backend error logs can include exception information and speech-language settings.

The website uses Vercel and Cloudflare hosting infrastructure. Their handling of service data is described in the Vercel privacy notice and Cloudflare privacy policy. If you contact support, we receive the email address, message, and any diagnostics or attachments you choose to send.

7. Retention and deletion

• Saved content. Your active library stays on your device and, when sync is on, in iCloud until you remove it. Deleting an item removes it from the visible library, but synchronization records and caches can remain.
• Sentences. A deleted sentence's shared record clears the text and explanation. An identifier, timestamps, a fingerprint of the normalized text, and related metadata remain to prevent stale copies from returning. These deletion records have no automatic expiration.
• Words. Hidden deletion records retain the word and can retain previously saved definition and learning fields in local or synced storage. They are used to prevent older copies from restoring the item and have no automatic expiration.
• Audio and caches. Cached audio can remain after a library item is deleted. Older audio is replaced as the cache fills; deleting a library item does not immediately erase every cached copy or device backup.
• Service records. AI content controls described above are separate from operational metadata, purchase records, and support correspondence. These records are retained according to the relevant service's policies, operational needs, and legal obligations. We do not promise a single fixed retention period across all services.

8. Sharing and advertising

We share information with the providers described above to supply their services, respond to support requests, protect users and the service, or meet legal obligations. We do not sell personal information, share it with data brokers, or use it to track you across other companies' apps and websites for advertising.

9. Your choices and rights

• Choose what text to submit. Avoid submitting passwords, financial account details, or confidential information. To avoid online AI processing, do not start online lookups or send selected text to the extension.
• Choose Local pronunciation to stop new online audio requests, and change iCloud Sync in Settings.
• Delete saved items in the app, subject to the retention details above. Manage existing iCloud data and backups through Apple's controls where available.
• Manage or cancel App Store subscriptions through Apple. Deleting app content or uninstalling Klars does not cancel a subscription.
• Depending on your location, you may have rights to access, correct, delete, restrict, object to processing, or obtain a copy of personal information. Contact support@chor.dev for a privacy request or help with retained data.

10. Security and international processing

Klars uses encrypted network connections to its online services. No system can guarantee absolute security. Our providers operate internationally, so information may be processed outside your country. Applicable protections and transfer arrangements depend on the provider, service, and law; see the linked provider policies.

11. Children's privacy

Klars is not intended for children under 13, and we do not knowingly collect personal information from children under 13. Contact us if you believe a child has provided personal information through Klars.

12. Changes and contact

We may update this policy as Klars or its providers change. We will publish the updated policy here with a new effective date. For questions or privacy requests, email support@chor.dev.