Wallet Diary — Privacy Policy

Last updated: 8/6/2026

Wallet Diary ("the App") is a personal expense-tracking app for iOS, published by Tak Yan. This page explains what data the App collects, how it's stored, and the one situation in which any of it is ever sent to a third party.

The short version

Everything you log — every expense, receipt photo, and setting — stays on your device by default. Nothing is ever sent anywhere unless you personally set up and enable the optional AI auto-fill feature in Settings, and even then, only the specific expense you're actively filling in is sent, only after you've explicitly agreed to it.

What the App stores, and where

Every expense you log — date, item, provider/merchant, cost, currency, category, notes, payment method, and any receipt photo you attach — is stored locally on your device using Apple's SwiftData framework. This data is kept in an App Group container so the Home Screen widget can read it, but it never leaves your device through that mechanism — the widget just reads the same on-device file the app writes to.

The App does not use iCloud sync, does not have a server-side account system, and does not transmit your expense data to the developer of this App under any circumstance. We (the developer) never see, store, or have access to your expense data.

On-device voice and receipt processing

Speaking an expense uses Apple's on-device Speech framework to convert your voice to text — this conversion happens entirely on your device; audio is never recorded to a file, stored, or sent anywhere, including to us or to Apple's servers.

Scanning a receipt photo, when no AI backend is configured (see below), uses Apple's on-device Vision framework to read text off the photo. This also happens entirely on-device.

Optional: the AI auto-fill backend

The App includes an optional feature that uses a large language model to read a full sentence ("120 for a latte at Starbucks") or a receipt photo and fill in the item, provider, cost, and category fields automatically. This feature:

Is off by default. It only exists if you deploy your own backend server and enter its URL in Settings → AI Category-Guessing Backend URL.
Asks permission before first use. The first time you actually use auto-fill with a backend configured, the App shows an alert explaining exactly what will be sent and to whom, and asks you to allow or decline it. Declining falls back to on-device parsing — nothing is sent, and you're never asked again.
Sends only what's needed for that one entry: the typed or spoken text of the expense you're currently entering, or the receipt photo you're currently scanning — never your full expense history, never data about other entries.

If you enable this feature, that data is sent to the backend server you deployed and control, which forwards it to one of the following third-party AI providers, depending on how you configured that backend:

Provider	What's sent	Provider's own privacy policy
Google (Gemini API)	Expense text or receipt photo	Gemini API Additional Terms of Service
Anthropic (Claude API)	Expense text or receipt photo	Anthropic Privacy Policy

Because you control the backend deployment yourself (see Backend/README.md in the App's source), you also control which provider is used and can review or delete any logs on your own hosting/API accounts directly with those providers.

Currency exchange rates

To convert between currencies, the App fetches current exchange rates from open.er-api.com, a free public API. This request does not include any of your personal or financial data — it's a generic request for that day's exchange rates, the same for every user of the App.

What we don't do

No advertising, and no ad networks or ad-tracking SDKs of any kind.
No analytics or usage-tracking SDKs.
We never sell or share your data with data brokers or advertisers.
No account creation, no login, no data tied to your identity on our end.

Your data, your control

Because everything is stored locally on your device, you're always in control of it:

Export: Settings → Export All Expenses (CSV) lets you export everything you've logged at any time.
Delete: deleting the App from your device permanently removes all locally stored data, including the widget's shared copy.

Children's privacy

The App is not directed at children under 13, and we do not knowingly collect personal data from children under 13.

Changes to this policy

If this policy changes, the "Last updated" date at the top of this page will change accordingly. Continued use of the App after a change constitutes acceptance of the updated policy.

Contact

Questions about this policy or your data can be sent to myjlchatpt@gmail.com.