Privacy Policy
Last updated: March 30, 2026
This Privacy Policy explains how your information is collected, used, and protected when you use the LangTo document translation service ("Service") at langto.ai.
1. Data Controller
The Service is operated by Shufen Li, an individual developer, under the brand name LangTo. For any privacy-related inquiries, contact us at contact@langto.ai.
2. Information We Collect
Account Information
When you create an account, we collect your email address and authentication credentials. If you sign in via a third-party provider (e.g., Google), we receive your name and email address from that provider.
Payment Information
When you subscribe to a paid plan or purchase credit packs, payment is processed by PayPal. We do not store your credit card details on our servers.
Uploaded Documents
When you use the Service to translate documents, we temporarily receive and process the files you upload. See Section 4 for details on how we handle your documents.
Usage Data
We automatically collect information about how you interact with the Service, including: pages visited, features used, file types translated, language pairs selected, translation credit consumption, and timestamps.
Device and Connection Data
We collect your IP address, browser type, operating system, and device identifiers when you access the Service.
3. How We Use Your Information
We use the information we collect to:
- Provide, maintain, and improve the Service
- Process translations and deliver results
- Manage your account and subscriptions
- Process payments and prevent fraud
- Send transactional notifications (e.g., translation complete, subscription renewal)
- Respond to support requests
- Monitor service performance and diagnose technical issues
- Comply with legal obligations
We do not use your information to send marketing emails unless you have explicitly opted in.
Legal Basis for Processing
Where required by law (such as under the GDPR), we process your data based on the following legal grounds:
- Contract performance: providing the Service, processing translations, managing your account, and processing payments.
- Legitimate interest: service monitoring, diagnostics, fraud prevention, and service improvement.
- Legal obligation: compliance with tax, accounting, and other legal requirements.
- Consent: marketing communications (only if you opt in).
4. Document Handling
Your documents are never used for AI model training.
We process your files solely to perform the translation you request. When you upload a document for translation:
- Your file is transmitted via encrypted connection (TLS) to our servers.
- The document content is sent to Google Gemini API for translation processing. Google's Cloud API terms state that customer content is not used for model training.
- For certain PDF files, document structure is parsed via TextIn, a document parsing service. Only the document content necessary for parsing is transmitted.
- Uploaded original files are automatically deleted within 24 hours after translation is complete.
- Translated result files are automatically deleted within 7 days after translation is complete.
- You may download your translated files before deletion. Once deleted, files cannot be recovered.
We retain translation metadata (such as file name, language pair, page count, credit usage, and status) while your account is active, for billing, support, and service reliability. This metadata is deleted within 30 days of account deletion.
5. Third-Party Services
We share data with the following third-party service providers, solely to operate the Service:
| Service | Purpose | Data Shared |
|---|---|---|
| Google Gemini API | AI translation processing | Document content (text) |
| TextIn | Document structure parsing (PDF) | Document content |
| PayPal | Payment processing | Billing details, email |
We do not sell your personal information to any third party.
6. Cookies
We use cookies for:
- Essential cookies: Authentication and session management. Required for the Service to function.
- Preference cookies: Storing your language and interface settings.
We do not use third-party advertising or tracking cookies. You can manage cookies through your browser settings.
7. Data Retention
- Account data: Retained while your account is active. Deleted within 30 days of account deletion, except where retention is required by law.
- Uploaded files: Deleted within 24 hours after translation completion.
- Translated files: Deleted within 7 days after translation completion.
- Translation metadata: Retained while your account is active. Deleted within 30 days of account deletion.
- Payment records: Retained as required by applicable tax and accounting laws.
8. Your Rights
You have the following rights regarding your personal data, subject to applicable law:
- Access the personal data we hold about you
- Correct inaccurate personal data
- Delete your account and associated personal data
- Export your personal data in a portable format
- Restrict or object to the processing of your personal data
- Withdraw consent at any time where processing is based on consent
- Lodge a complaint with your local data protection authority
You may also have additional rights under the laws of your jurisdiction. We will not discriminate against you for exercising your privacy rights.
To exercise any of these rights, contact us at contact@langto.ai. We will respond within 30 days.
9. International Data Transfers
Your data may be processed in countries other than your own, as our third-party service providers operate globally. We take reasonable steps to ensure your data is protected in accordance with this Privacy Policy and applicable law.
10. Data Security
We protect your data with encryption in transit (TLS) and access controls on our systems. No method of transmission or storage is 100% secure, and we cannot guarantee absolute security.
11. Children's Privacy
The Service is not intended for users under 16 years of age. We do not knowingly collect personal data from children under 16. If we become aware that we have collected such data, we will delete it promptly.
12. Changes to This Policy
We may update this Privacy Policy from time to time. We will notify you of material changes by email and by posting the updated policy on our website at least 14 days before they take effect.
13. Contact Us
If you have questions about this Privacy Policy or wish to exercise your privacy rights, contact us at:
Email: contact@langto.ai