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Your practice, on every device.

Privacy policy

Last updated: October 6, 2026

This policy describes Shadowy, the iPhone app and the practice app at shadowyapp.xyz, provided by HINODE GIKEN K.K.

Your account

You can sign in with Apple, Google, or an email address and password. Accounts are run by Firebase Authentication, a Google service. It keeps your email address, the name your sign-in provider shares (if any), and an account ID. If you use Sign in with Apple and choose to hide your email, we receive an Apple relay address instead. Passwords are handled by Firebase; we never see them.

What’s saved with your account

This is stored in Google Cloud Firestore and Cloud Storage for Firebase, in Tokyo, Japan, and can only be read by your signed-in account. See Firebase’s privacy information. The iPhone app also keeps a copy on your phone so you can practice offline; changes you make offline are saved to your account when you’re back online. Photos and screenshots you pick are used on your device only and are never uploaded.

Camera, photos, and microphone

The camera and photo picker let you choose text to practice. Text recognition runs on your device. The microphone is used only while you record a take, which is saved with your account as described above, or turn spoken audio into text with your device’s speech recognition, which follows your device provider’s privacy terms and isn’t saved by Shadowy. You can deny or revoke permissions in device or browser settings; pasting text and listening don’t need camera or microphone access.

Reference audio

When you add a list, Shadowy splits it into sentences and sends those sentences, your chosen language, and your chosen voice to Shadowy’s server, which is hosted on Vercel. Only the text is sent; your recordings and images are not. The server sends each sentence to ElevenLabs, a third-party text-to-speech service, to create natural-sounding reference audio. ElevenLabs processes that text under its privacy policy.

Generated audio files are stored on Vercel Blob storage at hard-to-guess web addresses and cached, so the same sentence doesn’t need to be created again. Your devices download them so you can practice offline. If reference audio can’t be created, for example when you’re offline, Shadowy uses your device’s built-in speech voice, which is governed by your device provider’s settings and privacy terms.

Pronunciation scoring

Pronunciation scoring is part of Shadowy Pro. When a Pro subscriber records a take in the iPhone app, the app sends that recording, the sentence it was practicing, and the language to Shadowy’s server, signed in with your account. The server checks your subscription and passes the recording and sentence to Microsoft Azure AI Speech, which returns accuracy, fluency, completeness, prosody, and word-by-word scores. Microsoft processes them under the Microsoft Privacy Statement. Shadowy’s server doesn’t keep the recording it sends; the score is saved with the take in your account. If you’re not subscribed to Shadowy Pro, recordings aren’t sent for scoring.

Payments

If you subscribe or buy extra minutes on the website, payment is handled by Stripe under its privacy policy. We receive your subscription status and purchase history, not your card details, and save your plan with your account.

Notifications and app settings

Notifications are optional. If you allow them, the app includes a device push token with its audio request so we can tell you when your audio is ready or couldn’t be created. The token is delivered through Expo’s push notification service and Apple Push Notification service; see Expo’s privacy policy. You can turn notifications off at any time in device Settings.

The iPhone app checks Firebase Remote Config for which features are turned on, using a random installation ID that isn’t linked to your account.

Deleting your data

Deleting a list on the website also deletes its takes and recordings from your account. To delete your account and everything saved with it, use Settings → Delete account in the iPhone app, or Delete account in the account menu at shadowyapp.xyz/app. This permanently removes your lists, takes, recordings, scores, settings, and sign-in. If you have a Shadowy Pro subscription that will renew, cancel it in Manage billing first; you can delete your account once it’s set to end. It doesn’t remove reference audio already cached on our storage, which isn’t linked to your account, or records Stripe must keep for past payments.

Deleting the app removes its copy on your phone but not your account. Your phone may include app data in device backups according to your settings; manage those backups with your device provider.

Sharing and tracking

We do not sell your data or use it to track you across other companies’ apps or websites, and Shadowy has no advertising or third-party analytics. Data is shared only with the services named above, only to provide Shadowy: Google (accounts and storage), ElevenLabs (reference audio), Microsoft (Pro scoring), Stripe (payments), Vercel (hosting), and Expo and Apple (notifications). Your lists and recordings are private to your account; there is no public feed or sharing.

This website

The practice app at shadowyapp.xyz/app uses the same account and data as the iPhone app, and saves takes you record in the browser to your account. Explore and the home page can be used without signing in. Hosting infrastructure may process connection information, such as your IP address and requested page, to deliver the website.

Changes and help

We will update this policy when Shadowy’s data practices change. For help with permissions, your account, or deleting your data, visit Shadowy support.