Card Number Formats

The cards can be identified by the format as described in following table:

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Note:

To validate whether the card was issued in India, you must use the check_isDomestic API by posting the first six digits of the card number. For more information, refer to the BIN APIs.

Card TypeCard Number Format
AMEXStarting with 34 or 37, length 15 digits.
VISAStarting with 4, length 16 digits.
MastercardStarting with 51 through 55, length 16 digits.
Diners ClubStarting with 300 through 305, 36, or 38, length 14 digits.
DiscoverStarting with 6011, length 16 digits or starting with 5, length 15 digits.
JCBStarting with 2131 or 1800, length 15 digits or starting with 35, length 16 digits.

Validating Card Number using LUHN Algorithm

You can use the LUHN algorithm to validate the card numbers when they enter their card details for payment. The following code block provides function to pass a card number, and receive a boolean value of true or false depending on whether the card is calculated to be valid by the LUHN algorithm.

| function luhn \# \<numeric-string\> {  num=\$1  shift 1    len=\${\#num}  is_odd=1  sum=0  for((t = len - 1; t \>= 0; --t)) {  digit=\${num:\$t:1}    if \[[ \$is_odd -eq 1 ]]; then  sum=\$(( sum + \$digit ))  else  sum=\$(( \$sum + ( \$digit != 9 ? ( ( 2 \* \$digit ) % 9 ) : 9 ) ))  fi    is_odd=\$(( ! \$is_odd ))  }    \# NOTE: returning exit status of 0 on success  return \$(( 0 != ( \$sum % 10 ) )) } |
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