AI for personal finance: how to use it safely to organize your money

Artificial intelligence tools have become good at tasks that used to feel like a chore: sorting hundreds of transactions, explaining a confusing credit card statement, building a budget from a list of expenses. For many people, it is the first time organizing their finances has felt quick.

At the same time, money is a subject where mistakes are expensive. Pasting an entire bank statement into any chatbot, accepting a calculation without checking it or handing your bank password to an unknown app can cause real losses. And scammers have also started using AI to sound more convincing.

Here you will see what AI does well in personal finance, what never to share, how to choose safe tools, how to check the numbers it gives you and which scams use AI, with practical examples in Brazilian reais (R$).

What AI does well in personal finance

Used the right way, AI saves time on repetitive tasks and helps you understand topics that seem complicated.

• Categorizing spending. Turning a cryptic line like "PAG*JOSE 0234" into "Food" is tedious for people and easy for a good AI, especially one that learns from your corrections.
• Summarizing and explaining. Asking "what did I spend the most on in the last three months?" or "what is this charge on my card statement?" gets answers in seconds.
• Running scenarios. "If I cut R$ 300 from delivery, how long until my emergency fund is complete?" is a calculation AI can set up, as long as you check it.
• Spotting patterns. Forgotten subscriptions, expenses that crept up slowly, duplicate charges.
• Teaching concepts. The CDI (the interbank rate that most Brazilian fixed-income investments track), Brazil's regressive income tax table on investments, compound interest: AI explains them at your pace, with examples.

What it should not do is make decisions for you or move money without your review. AI organizes and suggests; the decision is still yours. If you are just starting to get organized, our guide on how to track expenses is a good starting point.

What never to share with a chatbot

This is the most important rule in this article. No legitimate money management tool needs the data below:

Before pasting a statement, delete your full name, CPF, account and branch numbers, names of other people that appear in transfers and any codes. For most analyses, AI only needs the date, a short description and the amount.

Safe tools: Open Finance vs sharing your password

There are two main ways an app can read your banking data.

Open Finance Brasil. This is the system regulated by Banco Central do Brasil, the central bank, and the National Monetary Council (CMN). You give consent inside your own bank's app or internet banking, choose which data to share, for what purpose and for how long (up to 12 months under the general rule), and you can revoke it at any time. Only institutions authorized by the Central Bank take part, and you never give your bank password to the third-party app. Our guide on what Open Finance Brasil is explains how it works step by step.

Screen scraping. The app asks for your bank username and password and logs into your account as if it were you. This violates banks' terms of use, gives far too much access, can break at any moment and increases the risk if the company suffers a data leak.

To use AI with your real data, prefer tools that connect through Open Finance with read-only access, meaning they cannot make Pix payments (Pix is Brazil's instant payment system) or transfers. Our article is Open Finance safe? explains the layers of protection and the real risks.

Checklist for evaluating an AI tool

1. Does it connect through Open Finance or ask for your password? If it asks for your password, walk away.
2. Is the access read-only?
3. Does the privacy policy explain what data is collected, why and for how long?
4. Can you request deletion of your data?
5. Does the company say whether it uses your data to train third-party AI models?
6. Is the app published in an official app store, by an identifiable company with a CNPJ (Brazilian company registration number)?

AI can be wrong: how to check the numbers

AI models sometimes "hallucinate": they confidently present a number or a fact that is not correct. In finance, that can lead to bad decisions. Some common errors:

• Adding values incorrectly or leaving out transactions.
• Ignoring taxes, fees or IOF (a Brazilian financial transactions tax) in investment simulations.
• Using outdated rates, such as an old Selic (Brazil's benchmark interest rate) or IPCA (the official inflation index).
• Citing rules that have changed or never existed.

Worked example: the simulation that forgot income tax

You ask a chatbot how much R$ 10,000 earns in a CDB (a bank certificate of deposit) paying 110% of the CDI over one year. It answers: "R$ 1,100". Let's check, assuming a hypothetical CDI of 10% a year, purely as an example:

• Gross return: 110% × 10% = 11% a year. R$ 10,000 × 11% = R$ 1,100.
• Income tax: over one year, the holding period exceeds 360 days, so the rate on Brazil's regressive table is 17.5%. R$ 1,100 × 17.5% = R$ 192.50.
• Net return: R$ 1,100 − R$ 192.50 = R$ 907.50.

The AI's answer was right for the gross amount, but it overstated by R$ 192.50 what would actually reach your account. When comparing with a Brazilian savings account (poupança), which is tax-exempt for individuals, that detail can change the conclusion.

Worked example: subscriptions found by AI

Now a use where AI really helps. You ask it to list recurring charges from the last few months, and it finds three subscriptions you no longer use: R$ 39.90, R$ 55.90 and R$ 21.90.

• Monthly total: R$ 39.90 + R$ 55.90 + R$ 21.90 = R$ 117.70.
• Total over one year: R$ 117.70 × 12 = R$ 1,412.40.

Before canceling, check your statement or card bill to confirm the charges really recur and the amounts match. Under Brazilian consumer rules, you should be able to cancel through the same channel you used to sign up.

Quick rules for checking

• Ask the AI to show the calculation step by step, not just the result.
• Redo the sum of the most important items on a calculator.
• Check current rates at official sources: the Selic at the Central Bank, the IPCA at IBGE (the national statistics institute), government bonds at Tesouro Direto.
• Be wary of any tax or legal rule you cannot confirm on the Receita Federal (Brazil's tax authority) website or another official site.

Scams that use AI

Scammers use AI too. The scams are the same as always, just more convincing.

• Cloned voices or videos. A "relative" calls or sends a voice message asking for an urgent Pix, in a voice that sounds like someone in your family. Agree on a code word with your family, or call back on the number you already know.
• Messages with perfect grammar. Fake call centers and fake bank employees are harder to spot from their writing. The rule still holds: banks never call asking for your password, a code or to "test" a Pix.
• Fake investment assistants. Profiles and "bots" promising high, guaranteed returns using AI. High guaranteed returns do not exist.
• Fake apps. Apps that imitate well-known AI tools to steal data or ask for your bank login.

If you fall for a Pix scam, dispute the transaction in your bank's app as quickly as possible and file a police report (boletim de ocorrência). Banks use the MED, the Central Bank's Special Return Mechanism, but a refund depends on there being money left in the scammer's account and is not guaranteed, so speed matters.

Your rights under the LGPD

Brazil's General Data Protection Law (LGPD, Law 13,709/2018) applies to any company that processes your data, including AI companies. You have the right to:

• Know what data the company holds about you and what it uses it for.
• Correct incomplete or inaccurate data.
• Request deletion of data processed on the basis of your consent.
• Revoke your consent.

With Open Finance, you can also cancel data sharing at any time, both in your bank's app and in the app receiving the data.

How Otto helps

Otto was designed to use AI without asking for what it should not:

• It connects accounts and cards through Open Finance Brasil, via the aggregator Malvo, with read-only access: it does not move money or make Pix payments, and it never asks for your bank password.
• It categorizes your spending with AI that learns from your corrections.
• In the chat, it answers questions about your own spending with charts, so you can check the numbers.

Otto is not a financial institution or an investment advisory service; it helps you organize and understand your money, and the decision is yours.

Official sources and further reading

• Open Finance Brasil
• Banco Central do Brasil (in Portuguese)
• General Data Protection Law, LGPD (Law 13,709/2018), in Portuguese