#1 Look for information about the seller. 

• Make sure the seller is credible: search the internet for the company name or ask friends or acquaintances for references.
• Be suspicious if you don't find an address or telephone contact details or the terms and conditions of the sale.
• Research and read about what other customers have experienced in relation to a particular product or online store, for example in discussion forums.

Be cautious about offers you can’t refuse or bargains because very often they are fraudulent.

#2 Check the security of the website or app.

• Check that the address you want to access begins with “https://” and that a padlock appears at the end of the address or in the bottom bar of the window. If this is not the case, the page is not secure.
• Only install apps from official app stores.
• Follow the usual security procedures to protect your computer, tablet or mobile phone:
• Keep antivirus and anti-spyware programs up to date and ensure the firewall is active;
• Don't click on links or download content from unknown sources;
• Don't use public or unknown wi-fi networks;
• Don't use public devices to make online payments.

Don't enter your data (name, mobile phone number, email, citizen card, bank account numbers or credit card numbers) on sites that you don't know or whose authenticity you don't trust.

#3 Read the terms and conditions.

• Check the available payment methods.
• Find out about any additional costs – for example, shipping costs or customs duties if the shop is based outside the European Union.
• Check the conditions and costs for returns and exchanges. Within the EU, you have 14 days to return any item bought over the internet.

#4 Make sure that you only provide the data required to complete the purchase.

• Be suspicious of requests for data (e.g. passwords, personal identification document data or payment card details) that seem excessive or strange to you, even if they come from an apparently reliable entity. If in doubt, ask your bank or other payment service provider for clarification via the official channels.

#5 Opt for a payment method with added security.

• Multibanco reference. If the seller offers this form of payment, they will send an SMS or an email with the details so that you can make the payment within a certain time limit at an ATM or via the home banking service.
• Cards with limited credit and a short validity period, such as prepaid cards. These cards limit the possibility of misusing the card and the sum of possible losses.
• Single-use virtual cards or with a limited amount and validity period. A virtual card is a card that is generated and used in an electronic context. At the time of the purchase, the real card data is not disclosed, making the transaction more secure. This feature may be offered by your bank or other payment service provider and by certain payment apps. 
• Payment instruments with added security. Choose cards with added security procedures such as the latest version of the 3D Secure service. As a rule, this service will already be active on credit or debit cards that allow you to make online purchases. If not, ask your bank or other payment service provider to subscribe/activate it. In this case, when making a purchase, you will usually be asked to perform strong customer authentication, that is, to enter two valid authentication elements, in addition to the 3D Secure card data. In Portugal, the most common solution for strong authentication of online card transactions is to validate the transaction in the app of your bank or other payment service provider.

#6 Keep records. 

• Keep records of your purchase, including information about the seller and its email address. Whenever possible, print screenshots of the transaction data.

#7 Check your account regularly.

• Check your account on a regular basis and make sure that the movements correspond to the purchases you have made.

#8 Report suspected fraud.

• If you suspect misuse or unauthorised use of your payment card, or if you suspect that your identification or validation details (such as access credentials to the home banking service) have been wrongfully used, report the situation immediately to your bank or other payment service provider, through the contacts provided or through the contacts disclosed on the Banco de Portugal’s website and on the Bank Customer Website.
• Report the situation to the nearest police authority (PSP, GNR or PJ) or the Public Prosecutor's Office.
• If necessary, ask your bank or other payment service provider to cancel the card or the home banking service access credentials.