# Amethyst Privacy Policy and Terms of Use

**App:** Amethyst (Android Nostr client)<br>
**Publisher:** Vitor Pamplona<br>
**Contact:** amethyst@vitorpamplona.com<br>
**Last updated:** 2026-09-15

Amethyst is free, open-source software (MIT License — see `LICENSE`). It is not a service. There is no Amethyst server, no Amethyst account, and the developer has no access to data stored on your device.

Amethyst lets you browse content from third-party Nostr **relays** that you choose. Those relays host the content. They are independent of Amethyst, with their own operators and their own policies.

This document explains what data leaves your phone, who can see it, and the standards that apply to use of the app.

## Privacy

### Data sent off-device

Using the app causes the following data to leave your phone:

- **Nostr events** you publish, sent to the relays you have configured.
- **Subscriptions** (filters describing what you want to read), sent to those relays.
- **Media uploads** (images, audio, video), sent to the media server you select.
- **Workout summaries**, when you choose to publish one — see [Health and fitness data](#health-and-fitness-data-health-connect) below.
- *(Google Play build, push notifications enabled)* a per-device push token, your public key, and a preferred relay, registered with Google Firebase Cloud Messaging so a notification proxy can wake the app.
- *(F-Droid build, push notifications enabled)* a per-device token registered with whichever UnifiedPush distributor you install (e.g. ntfy).

The developer does not run any server that aggregates or stores this data.

### Data stored on your device

Configuration, cached events, keys, drafts, and other operational data live in the app's local storage. Other apps cannot read it on a standard, non-rooted Android device. You can wipe it by clearing the app's storage or uninstalling.

### Health and fitness data (Health Connect)

Amethyst's **My Fitness** screen (drawer → You → My Fitness) summarises your own training for you: how much you did this week against last week, how your time splits across activities, your best efforts, how many days you trained, and your current streak. It builds that picture from the workouts your watch or fitness app has already saved to **Android Health Connect**.

This is what the health permissions are for. The summary is computed on your phone and shown to you; nothing is sent anywhere to produce it, and you never have to post anything to use it.

My Fitness also counts the workouts you have logged in Amethyst itself, so it works whether or not you connect Health Connect. Connecting adds the sessions your watch recorded and the details a hand-typed workout does not carry — heart rate, steps and climb.

Separately, you may choose to publish one workout as a Nostr post (a NIP-101e kind 1301 event) so the people who follow you can see it. That takes a deliberate tap on "Share this workout", shows you the pre-filled post, and waits for you to confirm. It is never automatic.

The feature is optional and off until you grant the permissions. Amethyst asks for them only when you open My Fitness or the New Workout composer — never on first launch.

**What Amethyst reads, and what each type is for:**

| Health Connect data type | Permission | What it is used for |
| --- | --- | --- |
| ExerciseSession | `READ_EXERCISE` | The workout itself: activity type, start and end. Drives your workout count, training time, per-activity breakdown, active days and streak. |
| Distance | `READ_DISTANCE` | Weekly distance, the change against last week, your weekly average, distance per activity, and your longest distance. |
| ActiveCaloriesBurned | `READ_ACTIVE_CALORIES_BURNED` | Weekly energy burned and its week-over-week change. |
| TotalCaloriesBurned | `READ_TOTAL_CALORIES_BURNED` | Fallback for the same figure, for watches and apps that only record total energy. |
| HeartRate | `READ_HEART_RATE` | Average and maximum heart rate per workout, your duration-weighted average for the period, and your highest heart rate. |
| Steps | `READ_STEPS` | Your weekly step average and your highest step count. |
| ElevationGained | `READ_ELEVATION_GAINED` | Your weekly climb average and your biggest climb. |

Health Connect groups a few data types under one permission: `READ_EXERCISE` also covers CyclingPedalingCadence and `READ_STEPS` also covers StepsCadence. Amethyst does not read, store, or publish cadence — those types come attached to the permissions above and are never requested separately.

**Limits on this access:**

- **Read-only.** Amethyst never writes to Health Connect.
- **Foreground only.** Reads happen only while the My Fitness screen or the New Workout composer is on screen. Amethyst does not request `READ_HEALTH_DATA_IN_BACKGROUND` and has no background health worker.
- **Last four weeks only.** Amethyst reads a rolling 28-day window and cannot see anything older. It does not request `READ_HEALTH_DATA_HISTORY`.
- **No location.** Amethyst does not request `READ_EXERCISE_ROUTE`, so it never receives the GPS track of a workout.
- **Nothing is uploaded automatically.** Health data stays on your device. The My Fitness summary is computed locally and never transmitted. A workout only leaves your phone if you tap "Share this workout", review the pre-filled post, and publish it yourself — one workout at a time. The developer runs no server; a published post goes to the Nostr relays you configured, and those numbers then become public like any other post you make.
- **No other use.** Health data is never used for advertising, analytics, profiling, or sale, and is never shared with third parties. It is not used to determine your eligibility for insurance, credit, or employment, and is not transferred to any such party.
- **Revocable.** Revoke the permissions in Health Connect at any time — My Fitness immediately drops back to its prompt — or turn the composer suggestions off under Settings → Compose Settings → "Suggest workouts to share". Amethyst keeps the summary and the suggestions only in memory; revoking access stops all reads immediately.

### What relays can see

A relay you connect to sees:

- Your IP address (or the Tor exit node when using it).
- Your public key.
- The events you publish (posts, reactions, reposts, reports, etc.).
- The filters you subscribe to.

A relay does **not** see the plaintext of:

- Private Direct Messages (encrypted to the recipient under NIP-17 / NIP-44).
- Private Zaps.

A relay can still see *that* you and another user are exchanging DMs even though it cannot read them. To reduce what a relay can correlate to you, route the app over a VPN or Tor.

### Media uploads

Uploads go to the media server you select. That server is independent of Amethyst and has its own policy. Anyone holding the resulting link — including media attached to a DM — can fetch the file.

### Public content is effectively permanent

Anything you publish to a relay can be copied to other relays or clients. Once published, you should assume it cannot be reliably deleted from the network.

## Child Safety Standards

These are the published Child Safety Standards for **Amethyst**, the Android Nostr client published on Google Play by **Vitor Pamplona**. They are published under Google Play's Child Safety Standards policy.

They are a community standard, not a license restriction. Amethyst's source code remains licensed under the MIT License in `LICENSE`.

### Prohibition

Using Amethyst to create, upload, share, solicit, or distribute child sexual abuse and exploitation (CSAE) material — including child sexual abuse material (CSAM) — or to groom, exploit, or harm a minor is prohibited and is illegal in essentially every jurisdiction.

### In-app tools

Amethyst provides:

- **Report Post** and **Report Account** — publish a signed Nostr report (including the "Illegal Content" reason) so relays and other clients can act on it.
- **Block Post** / **Block Account** — hide content locally on your device.
- **Block Relay** — add a relay to your NIP-51 Blocked Relay List so the app stops fetching from or publishing to it. This is the strongest tool the app offers against a relay that refuses to moderate.
- **Mute Words / Hashtags** — filter unwanted content from your feeds.

### Addressing CSAM

Amethyst does not host content, so the app cannot remove CSAM. Only the relay hosting the content can remove it. In the United States, 18 U.S.C. §2258A makes hosting providers — not viewer applications — the entities required to report to the National Center for Missing & Exploited Children (NCMEC).

If you encounter CSAM through Amethyst:

1. Report the content in-app and select "Illegal Content."
2. Add the hosting relay to your Blocked Relay List.
3. Report directly to **NCMEC** at https://report.cybertip.org/ (United States) or to an **INHOPE** hotline at https://www.inhope.org/ (other jurisdictions). These bodies can compel the hosting provider to act.
4. You may also email **amethyst@vitorpamplona.com** with the relay URL and event ID. The developer cannot remove content from third-party relays, but may forward the report to relay operators it is in contact with and may stop recommending the offending relay in any list shipped with the app.

### Compliance

Amethyst is distributed under Google Play's Child Safety Standards policy and applicable law. Obligations attached to the **hosting** of content rest with relay operators.

### Age rating

Amethyst's Google Play listing is rated 17+. The app does not request or store age information.

## Terms of Use

### Google Play build

You agree not to use the Google Play build of Amethyst to submit Objectionable Content to relays. Objectionable Content includes:

- Sexually explicit material.
- Obscene, defamatory, libelous, slanderous, violent, or unlawful content.
- Content that infringes third-party rights (copyright, trademark, privacy, publicity).
- Content that is deceptive or fraudulent.
- Content promoting illegal drugs, tobacco, firearms, ammunition, or illegal gambling.

These Terms apply only to the Google Play distribution of Amethyst.

### F-Droid and other source-built distributions

The MIT License in `LICENSE` is the only instrument governing your right to use, study, modify, and redistribute the software. No additional terms are imposed on these builds. Any dispute over distribution through F-Droid is between you and F-Droid.

## Updates

This document may change. The current version is published at https://github.com/vitorpamplona/amethyst/blob/main/PRIVACY.md.