This service validates credit numbers using the luhn algorithm. Api can be accessed at http://credit-card-api-service.herokuapp.com
The link below is an example of an invalid card number.
The card_number value can be changed to whatever number you would like to validate. The service will return a json string containing the number you entered and the card's validation status. e.g.
{"card":"4024097178888052","validated":false}
If the number you enter is valid then validated will be equal to true.Below is a valid card number that you can try.
card_number=4916603231464963