IFSC code checker

An IFSC is eleven characters. The first four letters identify the bank. The fifth character is always the digit zero, reserved by RBI for future use. The last six characters identify the branch and can be letters or digits. There is no checksum, so unlike an IBAN, a mistyped branch code produces another well-formed IFSC rather than an invalid one.

That is why format validation catches far less for IFSC than for IBAN. It catches the wrong length, digits in the bank code, and above all the letter O in fifth position. It cannot catch a wrong but well-formed branch.

In many fonts the capital letter O and the digit 0 are nearly indistinguishable, and the fifth character of every IFSC is a zero. Typing the letter is one of the most common IFSC entry errors. A validator should name it specifically, because a customer told only that the code is invalid will check every other character and still not see it.

RBI publishes the authoritative list of IFSC and MICR codes. A payment flow that relies on IFSC should check against a current copy of that list or a service built on it, not on format alone, and should be tested with a code that is well formed but does not exist.

Mergers make this matter more than it appears. Between 2019 and 2020, Vijaya Bank and Dena Bank merged into Bank of Baroda; Oriental Bank of Commerce and United Bank of India into Punjab National Bank; Syndicate Bank into Canara Bank; Andhra Bank and Corporation Bank into Union Bank of India; and Allahabad Bank into Indian Bank. Their old IFSC codes were retired. A beneficiary saved years ago may still hold one, so test what your system does with a well-formed code from a bank that no longer exists.

IFSC routes NEFT, RTGS and IMPS transfers to an account number. UPI payments to a virtual payment address do not need one, which is why a payment screen offering both should only ask for an IFSC on the account-transfer path. Asking for it on every path is a usability defect, and making it optional on the account path is a functional one.