Privacy Policy
Last updated: 1 November 2026
Koe (声) is a family voice companion: an adult child records a short sample of their own voice, and Koe's AI speaks with their parent in that familiar voice — while keeping the family in the loop. This policy explains what personal information we collect to make that work, how we use and share it, and the choices you have.
It applies to the Koe mobile app for Android and iOS (app id me.heyjoseph.koe) and to this website, koe.heyjoseph.me.
The short version: we collect only what the service needs — your account details, the recordings you choose to make, and the conversations the companion has, so it can speak and stay in context. We show no ads, run no third-party analytics trackers, and never sell your data. You can delete your account and everything attached to it at any time, from inside the app.
01 Who we are
Koe is developed and operated by the Koe team in Tokyo, Japan ("Koe", "we", "us"). We are the business operator responsible for the personal information described in this policy.
For anything privacy-related, contact us at koe.feedback@heyjoseph.me.
02 Information we collect
Everything below is collected directly from you, or from your device, in the course of using Koe. We have no advertising or analytics SDKs in the app, and we do not buy data about you from anyone.
- Account
- A phone number or email address, used to send one-time login codes — Koe has no passwords. If you sign in with Apple or Google instead, we receive the name and email address your account shares. You can also start anonymously and add contact details later.
- Profile
- Your display name, an optional profile photo, and your role (family member or parent). Profile photos are stored at public links — anyone with the exact link can view them.
- Your voice
- To create your companion voice you read a short passage aloud (a few minutes of audio). Those recordings are sent to our voice provider to build a voice model tied to your profile.
- Companion calls
- During an AI call, each spoken turn is recorded on the device, converted to text by our speech-to-text provider, answered by our AI provider, and spoken back in the cloned voice. Both sides of the conversation are stored as text transcripts on our servers. We do not keep the audio of companion calls — synthesized speech is deleted from the device after it plays, and only the text remains.
- Family calls
- Direct calls, and moments where a family member steps into a companion call, stream live between devices through our real-time calling provider. These human-to-human calls are not recorded and not transcribed.
- Greeting video
- Optionally, you can record a short camera-and-microphone video so your parent can see who set Koe up. It is stored privately and shared only through expiring links.
- About your parent
- The details you provide to personalize the companion: your parent's name, your relationship, their approximate age, topics to bring up or avoid, formality, and free-form notes. If you set up Koe for a parent, you are responsible for having their permission and showing them this policy.
- Usage records
- When calls start and end and how long they last, daily usage against free-plan limits, scheduled call times and timezones, and invitation status.
- Device & diagnostics
- Push-notification tokens; crash and error reports (device model, OS version, IP address, account identifier); and screen replays from a small sample of sessions, used for debugging, in which on-screen text and images are masked.
- This website
- Stores a single functional cookie (koe-lang) remembering your language choice. No advertising or analytics cookies.
03 How we use information
- Run the service: build and play your companion voice, transcribe and respond during calls, connect family calls, and deliver notifications about call activity to linked family members.
- Personalize conversations using the profile details you provide.
- Operate scheduling, invitations, and free-plan limits.
- Keep accounts secure: one-time login codes, Apple/Google sign-in, and bot protection on login.
- Diagnose crashes and fix bugs.
- Respond when you contact us.
We do not use your information for advertising, do not sell it, and do not profile you for any purpose unrelated to Koe. Conversation transcripts are used to operate the companion — including keeping context in a conversation and powering family check-in features — not for marketing.
04 Voice cloning and consent
- You may only clone your own voice. The recording flow is deliberate — you read a passage aloud yourself, and by submitting it you consent to us creating a synthetic voice from it. Cloning another person's voice without their consent is prohibited.
- Your parent is never deceived. Every companion call begins with the AI identifying itself in your voice ("It's [your name]'s AI"), an AI badge stays on screen for the whole call, and the companion answers honestly if asked whether it is real.
- You can re-record or delete your voice at any time. Re-recording replaces the old model; deleting your voice or your account also removes the voice model held by our voice provider.
A voice can identify a person, so we treat voice recordings and voice models as sensitive data: they are used solely to synthesize your companion's speech, shared only with the providers listed below, and never sold or used to identify you anywhere else.
05 What your family can see
Koe is a family product, so some activity is shared inside your family by design:
- The family member who set up a parent profile can see that profile's call activity — when calls happen, how long they last, and whether scheduled calls were missed.
- Summaries or transcripts of companion conversations may be shown to that family member as part of check-in features.
- Parents see the name, photo, greeting video, and cloned voice of the family member who invited them.
06 Service providers
Koe is built on a small set of specialist providers. Each processes personal data only as needed to provide its service to us, under data-processing terms:
- Supabase
- Hosting: database, authentication, file storage, and server functions.
- ElevenLabs
- Builds the cloned voice from your recordings and synthesizes companion speech.
- Deepgram
- Converts call audio to text.
- Anthropic
- Generates the companion's replies from conversation text.
- LiveKit
- Carries real-time audio for family calls.
- Twilio
- Delivers SMS login codes.
- Apple & Google
- Optional sign-in, and push-notification delivery (APNs, Firebase Cloud Messaging).
- Sentry
- Crash reporting and diagnostics.
- Cloudflare
- Hosts this website, and provides bot protection on the login screen (Turnstile).
- Expo
- Delivers app updates.
Beyond these providers, we disclose personal data only if the law requires it, or when necessary to protect the life or safety of a user. We never sell personal data and never share it with advertisers or data brokers.
07 International data transfers
Koe is operated from Japan. Several of the providers above process data outside Japan — in particular in the United States (for example ElevenLabs, Deepgram, Anthropic, Sentry, Twilio, Cloudflare, Apple, and Google). Where personal data crosses borders, we rely on the safeguards required by Japan's Act on the Protection of Personal Information (APPI), including providers' contractual commitments to equivalent protection.
08 How long we keep data
- Account, profile, and parent-profile details: for as long as your account exists.
- Voice models and recordings: until you re-record, delete the voice, or delete your account.
- Transcripts and call records: for as long as your account exists, then deleted with it.
- Companion call audio: never stored on our servers; synthesized speech is deleted from your device after playback.
- Invitation links: expire automatically after 24 hours.
- Crash reports and screen replays: kept for a limited period by our diagnostics provider, then deleted.
09 Deleting your data
- In the app: Profile → Delete account. This permanently removes your profile, your voice clone (including the model held by our voice provider), photos and greeting videos, parent profiles, transcripts, call history, and notification tokens.
- From outside the app: email koe.feedback@heyjoseph.me from the address on your account (or include your account phone number), and we will verify the request and delete the account for you.
- Partial deletion: you can delete a single parent profile, or just your voice, from inside the app without deleting your account.
Deletion takes effect immediately in our live systems; residual copies in encrypted backups are purged automatically on a rolling basis. We may retain the minimum records needed for security, fraud prevention, or legal compliance, and only for as long as those reasons apply.
10 Security
- All traffic between the app, our servers, and our providers is encrypted in transit (TLS/HTTPS).
- There are no passwords to steal: sign-in uses one-time codes or your Apple/Google account, and session tokens are stored in your device's secure storage (iOS Keychain / Android Keystore).
- Database access is enforced row by row, so an account can only read its own family's data.
No system is perfectly secure, but we deliberately collect little, keep call audio out of storage, and restrict who can access what.
11 Your rights
You can see and change most of your data directly in the app. Beyond that, subject to the APPI and other applicable laws, you can ask us to disclose the personal data we hold about you, correct it, delete it, or stop using or sharing it. Email us at the address below and we will respond as the law requires. You can also lodge a complaint with your local supervisory authority — in Japan, the Personal Information Protection Commission (PPC).
12 Children
Koe is built for adults: family members who set up a companion, and elderly parents who talk with it. It is not directed at children, and you must be 18 or older to create an account. We do not knowingly collect personal data from children — if you believe a child has given us data, contact us and we will delete it.
13 Changes to this policy
As Koe evolves we will update this policy, post the new version at this address, and change the date at the top. For material changes we will also tell you in the app before they take effect.
14 Contact us
Koe · Tokyo, Japan
Privacy contact: koe.feedback@heyjoseph.me — we aim to respond within a few business days.