1. Inputs:

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   • Card Number: The number entered by the user (e.g., "4111111111111111").

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   • Card Type: The type of credit card (e.g., Visa, MasterCard, etc.).

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2. 
   

3. Card Type Detection:

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   • Visa: Starts with "4" (usually 13 or 16 digits).

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   • MasterCard: Starts with "5" or "2" (16 digits).

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   • American Express: Starts with "3" and has 15 digits.

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   • Discover: Starts with "6" (16 digits).

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   Based on the first digit(s) of the card number, you can match the card type.

4. 
   

5. Action in OutSystems:

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   • Input Fields: For the user to enter the card number and card type.

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   • Server Action: Create an action to check the card type based on the card number entered.

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   • Feedback: Show whether the entered card is valid or invalid based on the detected card type.

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6. 
   

This method allows you to identify and validate credit card types without additional complex algorithms.