Effective date: TBD before public release. Last updated: June 03, 2026.

The short version

Lucy TTS does not have servers that store anything about you.

If you want the long version with specifics, read on.

Who this policy applies to

This policy describes Lucy TTS, an open-source app for macOS and iOS by Lucian Chapar. The full source is available at https://github.com/lucy-chapar/LucyTTS.

This policy does not apply to Fish Audio, Apple, or any other third party. See the Third parties section below.

What Lucy stores on your device

Data Where it’s stored Why
Your Fish Audio API key System Keychain (kSecAttrAccessibleAfterFirstUnlockThisDeviceOnly) So Lucy can call Fish on your behalf. Never leaves your device except to authenticate with Fish.
Voice presets (name, Fish voice ID, your notes) UserDefaults So you can switch between voices.
Lucy settings (speed, volume, format, latency, style cue, output device, meeting mode, spelling/grammar toggles) UserDefaults So your preferences persist between launches.
Phrase preset edits UserDefaults So your custom quick-phrases persist.
A flag indicating that an API key is saved, plus a masked suffix of that key (e.g. ********xYz) UserDefaults So the settings screen can show “you have a key on file” without exposing the key itself.
The current session’s typing queue and recently spoken history In memory only, cleared when Lucy quits So the queue and the “Replay last” button work.
Generated audio for the current sentence In memory only, played, then discarded Lucy never writes audio to disk.

Everything in the table above stays on your device. None of it is sent to us; we have no servers to send it to.

What Lucy sends over the network

Lucy makes network requests only to Fish Audio, only when you ask it to synthesize a sentence, test your API key, browse Fish’s voice catalog, or preview a voice sample.

Destination When What’s sent
https://api.fish.audio/v1/tts When you press Speak or use “Test connection” The text you typed, your API key (in an Authorization header), and the synthesis settings you chose (voice ID, speed, volume, format, latency, style cue).
https://api.fish.audio/model When you open Lucy’s built-in voice browser Your API key, and the search/list parameters you chose.
https://api.fish.audio/model/{voice_id} When Lucy needs the name/notes for a specific voice Your API key.
Voice sample audio URLs returned by Fish (typically Fish-operated CDN hosts) When you tap a voice in the browser to preview it An HTTPS request to a URL Fish gave us.

That’s the entire list of network destinations Lucy currently uses. Lucy does not contact any other server. There is no Lucy backend, no analytics endpoint, no crash reporter, no update server, no third-party SDK.

What Lucy does not do today

Future measurement, if and when

We may eventually add lightweight measurement to help improve the app — for example, an anonymized count of how often a particular error type occurs across all users, or an on-device count of crashes that you opt to share when you encounter one. If we do, it will follow these rules:

  1. Hard line: the actual text you type to synthesize will never be sent to a Lucy server, no matter what. Any future measurement will exclude user-generated text.
  2. It will use the privacy standards Apple expects for the App Store — anonymized, aggregated where possible, declared accurately in the App Privacy details, and compliant with applicable international privacy law (GDPR, UK GDPR, CCPA/CPRA).
  3. It will be disclosed on this page before it ships, not after.
  4. Where the law requires consent (most of the EU/UK), it will be opt-in. Elsewhere it will at minimum be disclosed and toggleable.
  5. The change will appear in the in-app release notes the first time you open a build that introduces it.

If those rules are ever broken, that’s a bug we want to fix immediately. Open an issue.

Third parties

Fish Audio

Lucy is a bring-your-own-key client for Fish Audio. When you use Lucy to generate speech, you are using Fish’s service under their terms and privacy policy, which you accepted directly when you signed up with them.

Apple

If you install Lucy from TestFlight or (in the future) the App Store, Apple has its own relationship with you for app distribution, crash reports, and (in TestFlight) beta feedback. Apple’s privacy policy applies to that relationship. Lucy does not enable Apple’s optional crash-and-usage sharing beyond what your device defaults are.

GitHub (this website)

This site is hosted on GitHub Pages. GitHub may log standard web server information (IP address, user agent, requested URL) when you visit. We do not run analytics on top of that and do not have access to it. See GitHub’s Privacy Statement for details.

Children

Lucy is not directed at children under 13. We do not knowingly collect data from children. (To be clear: we don’t knowingly collect data from anyone, but the legal language matters.)

Developer escape hatch (macOS only)

When developers run Lucy from a terminal using the Swift command-line tools (e.g. swift run LucyTTS), they would normally have to paste their Fish Audio API key into the app each time they relaunch a freshly-built debug binary, since the macOS Keychain entry is per-installed-app. To avoid that friction, Lucy on macOS will read an environment variable named FISH_AUDIO_API_KEY and use it as a fallback when no key is in the Keychain.

This is a developer convenience, not a feature normal users interact with. The variable is only honored on macOS. iOS does not have this fallback. Normal installed .app / TestFlight builds will not have this environment variable set unless someone explicitly launches them from a shell that defined it. If you did not set this variable yourself, it is not set.

Changes to this policy

If we ever change what Lucy collects, transmits, or stores, we will:

  1. Update this page with a new “Last updated” date and a brief note explaining what changed.
  2. Note the change in the Lucy release notes.
  3. For changes that meaningfully expand what we do with your data, surface the change inside the app the next time you open it.

Contact

Verifying these claims

Lucy is open source under AGPL-3.0. You don’t have to take our word for any of this. The relevant code is:

If you find a place where Lucy’s behavior contradicts this policy, please open a GitHub issue — that’s a bug we want to fix immediately. For sensitive disclosures, email lucychapar@pm.me instead.