Introduction

Gastón (“we”, “our”, or “us”) is committed to protecting your privacy. This Privacy Policy explains how we collect, use, and safeguard your information when you use our application.

Want this in plain language instead? How I handle your data answers the same questions without the legal phrasing. This page remains the binding version.

Information We Collect

Personal Information

• Account Information: Email address, name, and authentication credentials
• Financial Data: Expense records, categories, budgets, and payment methods you create
• Usage Data: App usage statistics and preferences
• Payment notifications (Android, optional): If you turn on automatic capture, the text of payment notifications from the apps listed on that screen. Only notifications from those apps that mention an amount leave your phone. We store that text encrypted, and an AI model may read it to extract the amount and the merchant. Nothing is read until you turn it on, and turning it off stops it.
• WhatsApp (optional): If you link your phone number, that number and the messages, receipt photos and voice notes you send Gastón there. See “Messages on WhatsApp” below.
• Splitwise (optional): If you connect your Splitwise account, the Splitwise expenses you are part of, your groups and categories, and your Splitwise user id. See “Splitwise” below.

Automatically Collected Information

• Device information (device type, operating system)
• Log data (access times, app features used)
• On Android, the device’s advertising ID (see Usage Analytics)

How We Use Your Information

We use the collected information to:

• Provide and maintain the Gastón service
• Manage your account and authenticate your access
• Store and organize your expense data
• Improve and optimize the app experience
• Send important updates and notifications (with your consent)

Data Storage and Security

• Your data is stored securely on our servers
• We use industry-standard encryption for data transmission
• We implement appropriate security measures to protect your information
• No other Gastón user can see your expenses, except the members of a book you create or join, who see what is in that book and your name and profile photo, never your email

Being straight with you: Gastón is not end-to-end encrypted. Your expenses are stored in a form our systems can read — that is what makes categories, budgets, reports and the assistant possible at all. So the small number of people who operate Gastón can technically reach the database, and do so only to keep the service running, investigate a bug, or help you with something you asked us about. Never to browse, never to sell, never for anything outside running Gastón.

Data Sharing

We do NOT:

• Sell your personal information to third parties
• Share your expense data with advertisers
• Use your data for purposes other than providing the Gastón service and, on Android, measuring our own advertising (see Usage Analytics)

We may share information only:

• With your explicit consent
• To comply with legal obligations
• To protect our rights and prevent fraud

Your Rights

You have the right to:

• Access your personal data
• Correct inaccurate data
• Delete your account and associated data
• Export your data
• Opt out of non-essential communications

Third-Party Services

Gastón may use third-party services for:

• Authentication (Google OAuth)
• Cloud hosting and storage
• Usage measurement and, on Android, measuring our own advertising (Google Analytics, Google Ads) — see “Usage Analytics” below
• AI features (Anthropic’s Claude models and, for voice notes, an OpenAI transcription model, both accessed through the Vercel AI Gateway) — see “AI Features” and “Messages on WhatsApp” below
• Messaging, if you link your number (WhatsApp, run by Meta) — see “Messages on WhatsApp” below
• Expense sharing, if you connect your account (Splitwise) — see “Splitwise” below

These services have their own privacy policies governing their use of your information.

AI Features

Some Gastón features use an AI model to turn your expense data into something readable — your Monthly Review summary, and, where available, the assistant that answers questions about your spending.

To do that, the relevant expense records are sent to Anthropic’s Claude models through the Vercel AI Gateway. That includes the descriptions you wrote, category names, amounts, dates and currencies, along with any question you type. It does not include your password, and it is limited to the data needed to answer the question at hand rather than your whole history.

The Monthly Review is read-only. The assistant can look at your data and, if you tell it about a purchase, draft an expense for you to accept, but it saves nothing itself and cannot edit or delete anything in your account.

Where the assistant is available, conversations with it are stored encrypted in our database so you can pick up where you left off. Starting a new chat deletes the conversation and every message in it, straight away. There is no conversation history to browse and no way to restore one, so this is not reversible. The only copies that outlive it are our encrypted backups, which hold it until they age out. Deleting your account removes everything else along with it.

Messages on WhatsApp

Where it is available, you can link your phone number and send Gastón an expense on WhatsApp: a text message, a photo of a receipt, or a voice note. Nothing is linked unless you do it yourself from the app.

Your messages travel through WhatsApp, which Meta runs under its own terms and privacy policy, not ours, and so do Gastón’s replies, which include the amount, the merchant and your category names. We store the number you linked, and WhatsApp’s identifier for your account, so we can tell that a message is yours.

To read what you sent, we pass it to Anthropic’s Claude models through the Vercel AI Gateway, which pick out the amount, the merchant and the date. A photo is sent as an image. A voice note is first sent to an OpenAI transcription model, through the same gateway, to turn the recording into text, and that text then goes through the same step.

We do not keep the recording or the photo: each is downloaded, read and thrown away. What we keep is your message, the transcript of your voice note, or a one-line description of the receipt, which is stored encrypted. We also keep the details read from it (amount, merchant, date and a suggested category) and the number it came from, so it can show in your Inbox.

Nothing you send becomes an expense on its own. It waits in your Inbox until you confirm it, in the app or by tapping a category in Gastón’s WhatsApp reply, and you can dismiss it instead. To stop, unlink your number in the app or send “baja” or “stop” on WhatsApp. Deleting your account removes what you sent along with everything else.

Splitwise

Where it is available, you can connect your Splitwise account so that your share of the expenses you split there shows up in Gastón. Nothing is connected unless you start it yourself from the app and approve it on Splitwise.

Once connected, we read the Splitwise expenses you are part of (their description, amount, currency, date, category and your share), your groups and categories, and your Splitwise user id. We read them only to record your share in the book you choose. When you connect, the last 30 days of your Splitwise expenses are imported. Gastón never writes to Splitwise: nothing is created, edited or settled there. Splitwise is run by Splitwise, Inc. under its own terms and privacy policy, not ours.

The category Gastón suggests for a Splitwise share is matched on our own servers and is not sent to the AI provider. Once imported, your share is an ordinary expense in your book, and the AI features described above read it like any other expense.

The access Splitwise gives us is stored encrypted, and we also keep your Splitwise user id and how your Splitwise groups and categories map to your books and categories, so a sync knows where things go and does not import the same expense twice.

To stop, disconnect Splitwise in the app. That stops the sync and deletes the stored access and your group and category settings. Gastón keeps a record of which Splitwise expenses were already imported, including their Splitwise expense ids and your Splitwise user id, so that connecting again does not import them a second time. The expenses already imported stay in your book, and you can delete them like any other expense. Deleting your account removes all of it, including that record.

Connected Assistants

Where it is available, you can connect an outside AI assistant, such as Claude or ChatGPT, to your Gastón account. This is separate from the AI features above. Nothing is connected unless you start it yourself and approve it on a Gastón screen.

A connected assistant can read the expenses, categories, budgets and balances in your book when it asks for them, including the descriptions and merchants you wrote, amounts, dates and currencies. In a book you share with other people, that includes what the other members added, and their names. It never receives your password. What it reads goes to the company that runs that assistant (for example Anthropic or OpenAI), which handles it under its own terms and privacy policy, not ours.

If you allow it when you connect, the assistant can also add an expense to your Inbox. It waits there until you confirm it, and it is not part of your expenses before that. The assistant cannot edit or delete anything in your account.

You can see every connection and end any of them in Settings → Assistants on the web. Ending a connection stops that assistant’s access straight away, and changing your password ends all of them. Our usage analytics record that a connection was made and which kind of request an assistant made, not what was asked or answered.

Usage Analytics

We collect usage analytics linked to your account — which features you use, such as logging an expense or opening the Monthly Review. This never includes amounts, merchant names, category names, or note text.

On Android, part of this is also reported to Google Analytics: which screens you open, a handful of actions (signing up, signing in, logging an expense, opening the Monthly Review or the calendar), your Gastón account ID (a random identifier, not your name or email) and the device’s advertising ID. We advertise the Android app through Google Ads, and this lets Google measure which of our ads lead to a sign-up. It is not used to show you ads inside Gastón, and ad personalization is switched off. It is not shared for advertising from devices whose language and region setting is in the European Economic Area, the United Kingdom or Switzerland. Turning usage analytics off turns all of this off as well.

Google keeps its copy under its own retention rules, so deleting your Gastón account does not remove what Google has already received.

You can turn this off at any time: in the web app, go to Settings → Privacy; in the mobile app, go to You → Preferences.

Children's Privacy

Gastón is not intended for users under the age of 13. We do not knowingly collect information from children under 13.

Changes to This Policy

We may update this Privacy Policy from time to time. We will notify you of any changes by:

• Updating the “Last Updated” date
• Sending an in-app notification
• Posting a notice in the app

Data Retention

We retain your data for as long as your account is active. When you delete your account:

• Your data will be permanently deleted within 30 days
• What you added to a shared book stays with that book for its other members, with your name, email and photo removed
• Backups may be retained for up to 90 days for disaster recovery

Separately, usage analytics events are deleted 180 days after they are recorded — automatically, and whether or not you delete your account.

International Data Transfers

Your data may be transferred to and processed in countries other than your own. We ensure appropriate safeguards are in place for such transfers.

Contact Us

If you have questions about this Privacy Policy or your data, please contact us:

• Email: maxivarela@gmail.com
• App: Use the in-app support feature

Consent

By using Gastón, you consent to this Privacy Policy and agree to its terms.