Legal
Privacy Policy
Last updated: May 1, 2026
1. Information We Collect
We collect: (a) account details — your name, nickname, email address, and phone number (used for account verification and support); (b) profile data — gender, country of origin, native language, and the languages you are learning; (c) voice and speech data — your microphone audio is transcribed on-device and the resulting text transcripts are stored on our servers to power AI coaching; (d) content you create — posts, comments, and messages you send within the platform, including any photos you attach; (e) device and usage data — device model, OS version, and anonymised usage analytics to help us improve the app; and (f) push notification tokens to deliver call and activity alerts.
2. How We Use Your Information
We use your data to: provide and improve NextStar; personalise your language learning experience; analyse your speech transcripts and conversation history with AI to generate real-time coaching feedback; process any subscription payments; send you call and activity notifications; provide customer support; and comply with legal obligations. We do not use your data to train AI models.
3. AI-Powered Features
NextStar's coaching features are powered by Grok, an AI model provided by xAI (x.ai). When you speak during a practice session or tag @Sora in a post, the following data is sent to xAI's servers: your speech transcript (converted from audio on your device), recent conversation history for context, your first name, native language, and country (included in the AI prompt to personalise responses), and any photos you attach to a post. Audio itself is never sent to xAI — only the text transcript. Data sent to xAI is processed under xAI's Privacy Policy. We do not share your data with xAI for training purposes. Speech-to-text conversion on iOS uses Apple's on-device SFSpeechRecognizer; on Android it uses Google's speech recognition service.
4. Information Sharing
We do not sell your personal information. We share data only with the following service providers who help us operate the platform: xAI (Grok AI — see 'AI-Powered Features' above); Supabase (database and authentication infrastructure); LiveKit (real-time voice and video transport for practice rooms); Expo (push notification delivery); and Sentry (crash reporting and error diagnostics — see 'Crash Reporting' below). We also share data with other users as part of your public profile, with legal authorities when required by law, and in connection with any business transfer or acquisition.
5. Crash Reporting & Analytics
We use Sentry (sentry.io) to automatically collect crash reports and error logs. This data includes device type, OS version, app version, and a stack trace of the error. It does not include your name, email, or the content of your conversations. Crash logs are retained for 90 days and then automatically deleted. This helps us identify and fix bugs quickly.
6. Data Retention
We retain your data for as long as your account is active. Speech transcripts and conversation history from practice sessions are stored for the lifetime of your account and deleted within 30 days of account deletion. Posts, comments, and messages you have shared publicly are removed from our servers within 30 days of account deletion. Crash logs collected via Sentry are retained for 90 days. Backup copies may persist for up to an additional 30 days in encrypted storage before being purged.
7. Your Rights
Depending on your location you may access, correct, delete, or export your data. You may also withdraw consent at any time where processing is based on your consent. To delete your account and all associated data, use the 'Delete Account' option in the app settings. For other requests, contact us at tranquang5014@gmail.com.
8. Data Security
We implement industry-standard security measures including TLS encryption in transit and encrypted storage at rest via Supabase. All AI requests are made server-side — your Grok API key is never exposed to the client. No method of transmission over the internet is 100% secure, so we cannot guarantee absolute security.
9. Children
NextStar is not directed to individuals under 12. Users aged 12–17 may use the app with the consent of a parent or guardian, who should review this Privacy Policy. If we learn we have inadvertently collected personal data from a child under 12, we will delete it promptly. Contact us at tranquang5014@gmail.com if you believe we have collected data from a child under 12.
10. Contact
Questions about this policy? Reach us at tranquang5014@gmail.com or write to us at An Bien Ward, Hai Phong City, Vietnam.