| # | Id | Type | Description |
| 1 | formId | string | Unique form identifier |
| 2 | amended | boolean | Amended |
| 3 | amendmentNumber | integer | Amendment number |
| 4 | incomeTypeCode | string | Box 1, Income code |
| 5 | grossIncome | number | Box 2, Gross income |
| 6 | chapterIndicator | string | Box 3, Chapter indicator |
| 7 | ch3ExemptionCode | string | Box 3a, Exemption code |
| 8 | ch3TaxRate | number (double) | Box 3b, Tax rate |
| 9 | ch4ExemptionCode | string | Box 4a, Exemption code |
| 10 | ch4TaxRate | number (double) | Box 4b, Tax rate |
| 11 | withholdingAllowance | number | Box 5, Withholding allowance |
| 12 | netIncome | number | Box 6, Net income |
| 13 | federalTaxWithheld | number | Box 7a, Federal tax withheld |
| 14 | escrowProceduresApplied | boolean | Box 7b, Check if federal tax withheld was not deposited with the IRS because escrow procedures were applied |
| 15 | subsequentYear | boolean | Box 7c, Check if withholding occurred in subsequent year with respect to a partnership interest |
| 16 | revisedReporting | boolean | Box 7d, Check if you are a qualified intermediary, withholding foreign partnership, or withholding foreign trust revising its reporting on Form 1042-S to report to a specific recipient. Added for tax year 2025 |
| 17 | otherAgentsTaxWithheld | number | Box 8, Tax withheld by other agents |
| 18 | recipientRepaidAmount | number | Box 9, Overwithheld tax repaid to recipient pursuant to adjustment procedures |
| 19 | totalTaxWithholdingCredit | number | Box 10, Total withholding credit |
| 20 | withholdingAgentTaxPaid | number | Box 11, Tax paid by withholding agent (amounts not withheld) |
| 21 | withholdingAgent | Form1042Agent | |
| 22 | form1042Recipient | Form1042Recipient | |
| 23 | accountNumber | string | Box 13k, Recipient account number |
| 24 | primary | Form1042Agent | |
| 25 | prorataBasisReporting | boolean | Box 15, Check if pro-rata basis reporting |
| 26 | intermediary | Form1042Agent | |
| 27 | payer | Form1042Agent | |
| 28 | stateAndLocal | StateAndLocalTaxWithholding | |