Privacy Policy

Last updated and effective date: October 25, 2026

This Privacy Policy describes how Ling0 ("Ling0," "we," "us," or "our") collects, uses, shares, and protects your personal information when you use our website and services (the "Service"). We are committed to protecting your privacy and being transparent about our data practices.

The data controller responsible for your personal information is Diego Valades, an individual based in Spain, European Union. You can contact the person responsible for privacy inquiries by emailing hola@ling0.app.

1. Information We Collect

Information you provide directly:

• Account information: Your email address and password (stored as a bcrypt hash) when you create an account, and the name, grammatical gender, and interface language you choose in Settings.
• Learning data: The languages you study, your level, your learning path, and your progress, including exercise answers, flashcard reviews, writing you submit, messages to the grammar tutor, and scenarios you create.
• Voice conversations: When you rehearse a conversation, your microphone audio is streamed to our voice providers (see Section 2) to recognise your speech and produce the conversation partner's replies. We store the text transcript of each conversation. We do not store recordings of your voice.
• Learner observations: Notes the Service derives from your practice, such as recurring mistakes or words you know, used to personalise your path. You can review and remove them in Settings.
• Messages to us: If you email us, we receive your email address and the content of your message.

Information collected automatically:

• Technical data: IP address, browser type, device type, pages requested, and similar information transmitted by your browser to us or to service providers that help operate the Service.
• Usage and cost records: Records of which AI features were used and how much they cost to run, so we can operate the Service within budget and prevent abuse.

When analytics is enabled, we use PostHog to measure page visits and milestones such as completing setup or practice. Events may be associated with an internal account identifier. We exclude learning content, email addresses, URL query strings, and login tokens. Advertising tracking and session replay are disabled.

2. Service Providers

We rely on a small number of service providers to operate the Service:

• Hosting and infrastructure: Railway hosts the application and stores the database and generated media needed to run the Service.
• Voice conversations: ElevenLabs processes your microphone audio and conversation content in real time to provide speech recognition, the AI conversation partner, and synthesised speech, and returns the transcript to us.
• AI language models: OpenRouter routes text, such as your writing, exercise answers, tutor messages, and conversation transcripts, to the AI model providers that generate corrections, feedback, translations, and your learning path.
• Email delivery: Resend processes transactional email and delivery metadata when we send account, login, or settings emails.
• Product analytics: PostHog processes page visits, practice milestones, an internal account identifier when signed in, and browser and device metadata to help us understand use of the Service. We use PostHog's US hosting region.
• Embedded videos: The Watch feature embeds YouTube videos using YouTube's privacy-enhanced mode (youtube-nocookie.com). When you play a video, YouTube (Google) may receive technical data such as your IP address and browser details and process it according to its own privacy policy.

3. AI Features

Ling0 is built on artificial intelligence. When you rehearse a conversation, you are speaking with an AI conversation partner, not a human; its voice is synthetic and the scene images are AI-generated. Corrections, grades, translations, observations, and your learning path are also generated by AI models.

• These outputs are for your own practice. They are not used for admission, certification, or any official assessment, and they may contain mistakes.
• We do not use your voice to identify you or to infer your emotions.
• We do not train AI models on your content. Our providers process it to return a response; how long they keep it is governed by their own terms (Section 2).

4. How We Use Your Information and Legal Bases

We use the information we collect to:

• Provide the Service, including conversations, feedback, and your personalised learning path (performance of our contract with you)
• Authenticate your account and manage your session (performance of contract)
• Communicate with you about your account and important service notifications (performance of contract)
• Respond to your support requests and inquiries (legitimate interest)
• Monitor usage and costs to keep the Service running and improve features (legitimate interest)
• Detect, prevent, and address technical issues, fraud, and abuse (legitimate interest)
• Comply with legal obligations (legal obligation)

We do not use your personal information for advertising or automated decisions that produce legal or similarly significant effects on you.

5. How We Share Your Information

We do not sell, rent, or trade your personal information. We share information only in the following limited circumstances:

• Service providers: The providers listed in Section 2 process information on our behalf to provide hosting, voice, AI, email, analytics, and video services.
• Legal compliance: When required by law, court order, or government regulation, or to protect the rights, property, or safety of Ling0, our users, or others.
• Business transfers: In connection with any merger, acquisition, or sale of assets, information may be transferred subject to the protections of this policy.

6. Cookies and Local Storage

We use strictly necessary cookies: a session cookie that keeps you signed in, and, if you choose to stay signed in, a "remember me" cookie. We also store your progress through the language setup flow in your browser's local storage so it survives a page reload. PostHog is configured without cookies, session storage, or local storage. We do not use advertising cookies.

7. Data Retention

We retain your personal information for as long as your account is active or as needed to provide and secure the Service. When you delete your account, your account and the learning data tied to it in our application database, including your profile, learning paths, progress, writing, tutor messages, conversation transcripts, observations, and custom scenarios, are deleted, and your sessions are ended.

Limited information may remain for a reasonable period in backups, security logs, email delivery records, or service-provider records according to their retention policies and our legal or security obligations. De-identified usage and cost records that are no longer linked to you may be retained after account deletion.

You can delete your account at any time from the Account tab of the Settings page.

8. Data Security

We implement appropriate technical and organizational measures to protect your personal information, including:

• Passwords are hashed using bcrypt — we never store passwords in plain text
• Cross-Site Request Forgery (CSRF) protection on all forms
• Secure session management with token rotation
• Recent re-authentication before changing your email, password, or deleting your account
• TLS encryption for data in transit

No method of transmission or storage is 100% secure, but we strive to use commercially acceptable means to protect your information.

9. Your Privacy Rights

Under the EU General Data Protection Regulation (GDPR) and Spanish data-protection law, you have the following rights regarding your personal information. Ling0 extends these rights to all users regardless of location:

• Access: Request a copy of the personal information we hold about you
• Correction: Request that we correct inaccurate or incomplete information
• Erasure: Request that we delete your personal information — you can do this yourself by deleting your account in Settings
• Restriction: Request that we limit how we use your information
• Data portability: Request your data in a structured, machine-readable format
• Objection: Object to processing based on our legitimate interests
• Withdraw consent: Withdraw any consent you have given, without affecting processing that happened before

To exercise any of these rights, email us at hola@ling0.app. We will respond within one month, as required by the GDPR.

You also have the right to lodge a complaint with a data protection authority. In Spain, this is the Agencia Española de Protección de Datos (www.aepd.es); you may also contact the authority in your country of residence.

10. Children's Privacy

The Service is not directed to children under the age of 16, and you must be at least 16 to create an account. We do not knowingly collect personal information from children under this age. If you believe a child has provided us with personal information, please email us and we will promptly delete it.

11. International Data Transfers

Several of our service providers are based in, or process data in, the United States and other countries outside the European Economic Area:

• AI text processing: OpenRouter (United States) receives the text described in Section 2 and routes it to AI model providers, which may process it in the United States or other countries.
• Voice conversations: ElevenLabs processes your microphone audio and conversation content, possibly outside the EEA.
• Email and video: Resend and YouTube (Google) may process data in the United States. PostHog analytics data is processed in its US hosting region.

Where a provider is certified under the EU–US Data Privacy Framework, the transfer relies on the European Commission's adequacy decision; otherwise we rely on the Standard Contractual Clauses in that provider's data processing terms. Countries outside the EEA may not offer the same level of protection as EU law. You can request more information about these safeguards by emailing us at hola@ling0.app.

12. Changes to This Policy

We may update this Privacy Policy from time to time. Any changes will be posted on this page with an updated "Last updated" date, and we will notify you of material changes by email or in the Service. We encourage you to review this page periodically.

13. Contact Us

If you have any questions or concerns about this Privacy Policy or your personal data, please email us at hola@ling0.app.