Credit Card Checker


Did you ever encounter trouble with your credit card in remote places? Didn't your credit card work while shopping during a flight? One reason could be that your card is not "offline capable". 

This app helps you to understand the capabilities, limitations, security settings of your credit or debit card by reading the contactless chip and simulating a transaction.  

Android App

You can find the Android app in Google Play Store: 

Supported USB Card Readers

Per default the app uses the build-in EMV/contactless reader in your smartphone. To read the ICC an experimental option is available to connect an external card reader via USB port. This requires a reader and a card that supports the T=0 or T=1 protocol with automatic voltage/baud settings.

The following readers have been tested:

The following readers are known NOT to be working properly:

Please feel free to give me any feedback. Please send me the protocol of the reader output via email.

Known issues

Some cards contain several application (e.g. German Girocards up to five!), therefore reading may cause a timeout. In that case, open the settings and switch off or try the settings:


The following permissions are needed by the app:

Helpful external links

The following links may be helpful. Please use them at your own risk, as I do not check the links regularly and are not responsible for the content:

Last update: 07th Apr 2024