ITIN/SSN format

SSN

Here are the SSA's criteria for SSNs that are not issued and should be considered invalid:

• SSNs with the number 666 in positions 1-3
• SSNs with the numbers 00 in positions 4-5
• SSNs with the numbers 0000 in positions 6-9

Also, SSN starting with number 9 are considered ITN (see below).

ITIN

If a participant enters an ITIN, the middle digits must follow the following logic. We should add this validation to the front end so the user doesn’t continue.

If the citizenship and/or residency is the United States, and the document id starts with 9 then, the 4th digit must be:

• 5 or7 or 9 followed by any digit (e.g. 912-50-1234)
• 6 followed by 0-5 (e.g. 912-60-1234)
• 8 followed by 0-8 (e.g. 912-80-1234)

If the format is invalid, an error will be thrown HTTP 400 with the following message: Invalid number. Please enter a valid SSN or ITIN.

Source: IRS.