Privacy Policy - Currency & Gold Converter

Introduction

Welcome to Currency & Gold Converter ("we," "our," or "us"). We built the app to work without accounts: we never ask for your name, email address, or phone number. This Privacy Policy explains the small amount of information the app does handle, why, and how you stay in control of it.

Information We Collect

Data Stored on Your Device

Your savings, currency list, and settings are stored locally on your device. They never leave it unless you turn on Cloud Sync, and even then they are encrypted first (see Cloud Sync below).

Anonymous User ID

On first launch, the app creates a random User ID on your device. It is not derived from your name, email, Apple Account, or any device identifier, and it cannot be used to identify you. It is used to:

Link your subscription purchases to the app
Check whether you have Premium when the app fetches exchange rates or uses Cloud Sync

You can see your User ID in the app under About & Support.

Subscription Information

If you subscribe to Premium, the payment is handled entirely by Apple. We never receive your name, email address, Apple Account details, or payment information.

Apple shares the purchase with RevenueCat, our subscription management provider, together with your anonymous User ID. RevenueCat then sends our server a limited record of your subscription:

Your anonymous User ID
The plan you purchased and whether it is active
When the current subscription period ends
The type and time of the latest subscription event, such as a renewal or cancellation

Advertising Identifiers

The free version of the app displays advertisements through Google AdMob. On iOS, the app asks your permission before AdMob can use your device's advertising identifier for personalized ads. If you decline, ads may still be shown, but without tracking you across other companies' apps and websites. Premium subscribers do not see ads. This information is collected and managed by Google, not by us.

Exchange Rate Requests

The app fetches exchange rates and metal and cryptocurrency prices from our server. These requests include your anonymous User ID so the server can give Premium subscribers more frequent rate updates. They contain no other information about you.

Cloud Sync

Cloud Sync is an optional Premium feature that keeps your savings and settings the same across your devices. It is off unless you turn it on, it needs no account, and it is designed so that we can store your data without being able to read it.

How It Works

When you turn on Cloud Sync, your device generates a random, 16-character sync code. You enter this code on your other devices to connect them. The code is never sent to us.
Two separate values are derived from the code on your device: an encryption key, which never leaves your devices, and an account identifier, which is sent to our server so it knows which copy to return. The derivation is one-way, so the account identifier cannot be used to work out the key or the code.
Before anything is uploaded, your data is encrypted on your device with XChaCha20-Poly1305. Our server only ever receives and stores the encrypted result, and has no way to decrypt it.
When two devices make changes at the same time, the devices themselves merge the changes, because only they can read the data.

What Is Synced

Savings: the amounts, currencies and assets, and labels you add
Settings: your currency list and its order, base currency, theme, language, number, time, and weight formats, haptics, which screens are shown, and savings screen display preferences

Cached exchange rates and your subscription details are not synced.

What Our Server Stores

For each sync account, our server stores only:

The encrypted copy of your data
The account identifier derived from your sync code
A revision number and size, used to keep your devices in step
A random ID created for the device that last uploaded changes, so the app can tell your devices apart. It is generated by the app and is not a hardware or advertising identifier.
When the account was created, last connected, and last updated

We do not store your sync code, your encryption key, your User ID, your IP address, or any readable version of your data with a sync account.

What Our Server Sees When You Sync

Each sync request includes the account identifier and your anonymous User ID. The User ID is used only to confirm that you have an active Premium subscription and to limit how many requests can be made in a short time. It is not saved with your sync account, so our records do not connect your synced data to your User ID or your subscription.

Stopping Sync and Deleting Your Cloud Copy

Stop syncing: in the app's Cloud Sync screen, choose Stop syncing. You can keep the cloud copy or delete it.
Delete cloud copy: the encrypted copy and its account record are erased from our server immediately and permanently, and your other devices stop syncing. Data on your device is not affected. Deleting requires an active Premium subscription.
If your subscription ends: syncing pauses. The encrypted copy is kept, and the app keeps your sync code, so syncing resumes if you subscribe again.
If you lose your sync code: nobody can decrypt the cloud copy, including us. Because it is not linked to your User ID or any identity, we also cannot locate it on your behalf.

Availability

Cloud Sync is available only in the iOS app. The web version of the app never connects to the sync service.

How We Use Information

We use the information above only to:

Provide exchange rates and prices
Verify whether you have an active Premium subscription
Store and deliver your encrypted Cloud Sync data
Display advertisements in the free version of the app
Prevent abuse of our servers

We do not sell your information, build profiles about you, or use it for marketing. The app does not include analytics or tracking tools of our own.

Data Storage and Security

All communication between the app and our server is encrypted in transit. Cloud Sync data is additionally encrypted end to end with a key that exists only on your devices, so a breach of our server would not expose its contents.

Our database does not store IP addresses. Like any online service, our hosting provider may process your IP address in order to deliver requests to our server.

Data Retention

Subscription record: kept so we can verify Premium, and updated whenever your subscription renews, changes, or ends.
Cloud Sync data: kept until you delete it, including after your subscription ends, so you can resume syncing later.
Abuse-prevention counters: held only in memory and discarded within minutes.

Third-Party Services

Our app uses the following third-party services:

Apple App Store: Processes Premium subscription payments. See Apple's Privacy Policy.
RevenueCat: Manages subscription status using your anonymous User ID and purchase information from Apple. See RevenueCat's Privacy Policy.
Google AdMob: Displays advertisements in the free version of the app. AdMob may collect advertising identifiers and other data as described in Google's Privacy Policy.

Exchange rate and price data comes from public market data sources. Our server collects it on its own schedule, so your requests are never passed on to those sources.

Your Rights and Data Control

Data on your device: delete it at any time by uninstalling the app or clearing its data in your device settings.
Cloud Sync data: delete it from the app's Cloud Sync screen, as described in Cloud Sync above.
Subscription record: email us your User ID and we will delete the record linked to it. Note that while a subscription is active, Premium features on our server will stop working until your next subscription event.
Advertising: on iOS, you can change tracking permission at any time in Settings > Privacy & Security > Tracking.
Subscriptions: manage or cancel in your Apple Account settings. See our Payment & Refund Policy.

Children's Privacy

Our service is not intended for children under the age of 13. We do not knowingly collect personal information from children under 13. If you are a parent or guardian and believe your child has provided us with personal information, please contact us.

Changes to This Policy

We may update our Privacy Policy from time to time. We will notify you of any changes by posting the new Privacy Policy on this page and updating the "Last updated" date.

Contact Us

If you have any questions about this Privacy Policy or want to make a request about your data, please contact us at:

Email: [email protected]