Version: 2.0.0

Update

Use this endpoint to update the information on existing M-941 forms that are already created for a specific employer (payer).

You cannot update a return once it has been transmitted.

POST StateFilings/MAWH/Update

Run in Postman

Request Body

Field	Type	Description
StateWHRecords	Object[]	Object to identify the records.
SequenceId	String	A unique identifier for this record. Size Range: ..50
ReturnHeader	Object	Contains business information.
TaxYear	String	The tax year for which the Form M-941 is to be filed. Allowed values 2025,2026
Qtr	String	The quarter for which the Form M-941 is to be filed. Allowed values "Q1", "Q2", "Q3", "Q4"
Business	object	Object to identify the Business Details.
BusinessId	Guid	Optional Use the unique Business ID (Generated by TaxBandits) that you received in the response of the Business CREATE Endpoint. If you do not have a Business ID, ignore the field. By giving the Business ID, you do not have to provide all the business information again.
PayerRef	string	Optional Your unique identifier for the payer. Can replace BusinessId in future requests. Size Range: 50
IsDefaultBusiness	Boolean	When set to TRUE, this business will be set as the default across requests that do not specify a business.
TINDetails	object	TIN information for the business.
Format	string	Specifies how the TIN is passed. Allowed values "PLAIN_TIN" — Pass TIN directly. "TOKENIZED_TIN" — Pass tokenized TIN.
TINType	string	Specify the TIN type of the business. Allowed values "EIN", "SSN", "QI-EIN", "ITIN", "WP-EIN", "WT-EIN", "NQI-EIN", "IRSN"
TIN	string	The TIN value according to the Format selected.
IndividualNm	object	Required when TINType is SSN. Provide individual name fields instead of BusinessNm.
FirstNm	string	The first name of the individual. Size Range: 20
MiddleNm	string	Optional Middle name of the individual. Size Range: 20
LastNm	string	The last name of the individual. Size Range: 20
Suffix	string	Optional Suffix of the individual's name. Allowed values "Jr", "Sr", "I", "II", "III", "IV", "V", "VI", "VII"
BusinessNm	string	Legal name of the business. Required when TINType is EIN. Size Range: 75
NameCtrl	string	Name control of the business as registered with the IRS. Size Range: 3..4
DBADetails	object[]	Optional DBA (Doing Business As) information.
DBANm	string	Name of the DBA. Size Range: 75
DBARef	string	Unique identifier for the DBA. Size Range: 1-50
DBAId	Guid	TaxBandits-generated DBA identifier.
Address	object[]	Address information of the DBA.
Address1	string	Street address or PO Box. Size Range: 46
Address2	string	Optional Suite or apartment number. Size Range: 46
City	string	DBA's city. Size Range: 50
ProvinceOrState	string	DBA's province or state name. When the country code is US: Allowed values "AL", "AK", "AZ", "AR", "CA", "CO", "CT", "DE", "DC", "FL", "GA", "HI", "ID", "IL", "IN", "IA", "KS", "KY", "LA", "ME", "MD", "MA", "MI", "MN", "MS", "MO", "MT", "NE", "NV", "NH", "NJ", "NM", "NY", "NC", "ND", "OH", "OK", "OR", "PA", "RI", "SC", "SD", "TN", "TX", "UT", "VT", "VA", "WA", "WV", "WI", "WY", "AS", "FM", "GU", "MH", "MP", "PW", "PR", "VI", "AA", "AE", "AP" When the country code is CA: Allowed values "AB", "BC", "MB", "NB", "NL", "NT", "NS", "NU", "ON", "PE", "QC", "SK", "YT" Note: The size range is set to 50 for all countries except the United States and Canada.
Zipcd	string	DBA's ZIP code. Size Range: 5-16
Country	string	DBA's 2-character country code. Allowed values "US","AF", "AX", "AL", "AG", "AQ", "AN", "AO", "AV", "AY", "AC", "AR", "AM", "AA", "AT", "AS", "AU", "AJ", "BF", "BA", "FQ", "BG", "BB", "BO", "BE", "BH", "BN", "BD", "BT", "BL", "BK", "BC", "BV", "BR", "IO", "VI", "BX", "BU", "UV", "BM", "BY", "CB", "CM", "CA", "CV", "CJ", "CT", "CD", "CI", "CH", "KT", "IP", "CK", "CO", "CN", "CF", "CG", "CW", "CR", "CS", "IV", "HR", "CU", "UC", "CY", "EZ", "DA", "DX", "DJ", "DO", "DR", "TT", "EC", "EG", "ES", "EK", "ER", "EN", "ET", "FK", "FO", "FM", "FJ", "FI", "FR", "FP", "FS", "GB", "GA", "GG", "GM", "GH", "GI", "GR", "GL", "GJ", "GQ", "GT", "GK", "GV", "PU", "GY", "HA", "HM", "VT", "HO", "HK", "HQ", "HU", "IC", "IN", "ID", "IR", "IZ", "EI", "IS", "IT", "JM", "JN", "JA", "DQ", "JE", "JQ", "JO", "KZ", "KE", "KQ", "KR", "KN", "KS", "KV", "KU", "KG", "LA", "LG", "LE", "LT", "LI", "LY", "LS", "LH", "LU", "MC", "MK", "MA", "MI", "MY", "MV", "ML", "MT", "IM", "RM", "MR", "MP", "MX", "MQ", "MD", "MN", "MG", "MJ", "MH", "MO", "MZ", "WA", "NR", "BQ", "NP", "NL", "NC", "NZ", "NU", "NG", "NI", "NE", "NF", "CQ", "NO", "MU", "OC", "PK", "PS", "LQ", "PM", "PP", "PF", "PA", "PE", "RP", "PC", "PL", "PO", "RQ", "QA", "RO", "RS", "RW", "TB", "RN", "WS", "SM", "TP", "SA", "SG", "RI", "SE", "SL", "SN", "NN", "LO", "SI", "BP", "SO", "SF", "SX", "OD", "SP", "PG", "CE", "SH", "SC", "ST", "SB", "VC", "SU", "NS", "SV", "WZ", "SW", "SZ", "SY", "TW", "TI", "TZ", "TH", "TO", "TL", "TN", "TD", "TS", "TU", "TX", "TK", "TV", "UG", "UP", "AE", "UK", "UY", "UZ", "NH", "VE", "VM", "VQ", "WQ", "WF", "WI", "YM", "ZA", "ZI"
Email	string	Optional Email address of the Business. Size Range: ..100
Address	object	Primary address of the business.
Address1	string	Street address or PO Box of the business. Size Range: 46
Address2	string	Optional Suite or apartment number of the business. Size Range: 46
City	string	City of the business. Size Range: 50
ProvinceOrState	string	Province or state name of the business. When the country code is US: Allowed values "AL", "AK", "AZ", "AR", "CA", "CO", "CT", "DE", "DC", "FL", "GA", "HI", "ID", "IL", "IN", "IA", "KS", "KY", "LA", "ME", "MD", "MA", "MI", "MN", "MS", "MO", "MT", "NE", "NV", "NH", "NJ", "NM", "NY", "NC", "ND", "OH", "OK", "OR", "PA", "RI", "SC", "SD", "TN", "TX", "UT", "VT", "VA", "WA", "WV", "WI", "WY", "AS", "FM", "GU", "MH", "MP", "PW", "PR", "VI", "AA", "AE", "AP" When the country code is CA: Allowed values "AB", "BC", "MB", "NB", "NL", "NT", "NS", "NU", "ON", "PE", "QC", "SK", "YT" Note: The size range is set to 50 for all countries except the United States and Canada.
ZipCd	string	ZIP code of the business. Size Range: 5-16
Country	string	2-character country code of the business. Allowed values "US","AF", "AX", "AL", "AG", "AQ", "AN", "AO", "AV", "AY", "AC", "AR", "AM", "AA", "AT", "AS", "AU", "AJ", "BF", "BA", "FQ", "BG", "BB", "BO", "BE", "BH", "BN", "BD", "BT", "BL", "BK", "BC", "BV", "BR", "IO", "VI", "BX", "BU", "UV", "BM", "BY", "CB", "CM", "CA", "CV", "CJ", "CT", "CD", "CI", "CH", "KT", "IP", "CK", "CO", "CN", "CF", "CG", "CW", "CR", "CS", "IV", "HR", "CU", "UC", "CY", "EZ", "DA", "DX", "DJ", "DO", "DR", "TT", "EC", "EG", "ES", "EK", "ER", "EN", "ET", "FK", "FO", "FM", "FJ", "FI", "FR", "FP", "FS", "GB", "GA", "GG", "GM", "GH", "GI", "GR", "GL", "GJ", "GQ", "GT", "GK", "GV", "PU", "GY", "HA", "HM", "VT", "HO", "HK", "HQ", "HU", "IC", "IN", "ID", "IR", "IZ", "EI", "IS", "IT", "JM", "JN", "JA", "DQ", "JE", "JQ", "JO", "KZ", "KE", "KQ", "KR", "KN", "KS", "KV", "KU", "KG", "LA", "LG", "LE", "LT", "LI", "LY", "LS", "LH", "LU", "MC", "MK", "MA", "MI", "MY", "MV", "ML", "MT", "IM", "RM", "MR", "MP", "MX", "MQ", "MD", "MN", "MG", "MJ", "MH", "MO", "MZ", "WA", "NR", "BQ", "NP", "NL", "NC", "NZ", "NU", "NG", "NI", "NE", "NF", "CQ", "NO", "MU", "OC", "PK", "PS", "LQ", "PM", "PP", "PF", "PA", "PE", "RP", "PC", "PL", "PO", "RQ", "QA", "RO", "RS", "RW", "TB", "RN", "WS", "SM", "TP", "SA", "SG", "RI", "SE", "SL", "SN", "NN", "LO", "SI", "BP", "SO", "SF", "SX", "OD", "SP", "PG", "CE", "SH", "SC", "ST", "SB", "VC", "SU", "NS", "SV", "WZ", "SW", "SZ", "SY", "TW", "TI", "TZ", "TH", "TO", "TL", "TN", "TD", "TS", "TU", "TX", "TK", "TV", "UG", "UP", "AE", "UK", "UY", "UZ", "NH", "VE", "VM", "VQ", "WQ", "WF", "WI", "YM", "ZA", "ZI"
ContactDetails	object[]	Details of the person the IRS can contact regarding the given business.
FirstNm	string	First name of the contact person. Size Range: 20
MiddleNm	string	Optional Middle name of the contact person. Size Range: 20
LastNm	string	Last name of the contact person. Size Range: 20
Suffix	string	Optional The suffix of the contact person. Allowed values "Jr", "Sr", "I", "II", "III", "IV", "V", "VI", "VII"
Phone	string	Optional Phone number of the contact person. Size Range: 10 digits
PhoneExtn	string	Optional Phone extension number. Size Range: 5
Email	string	Optional Email address of the contact person. Size Range: ..100
Fax	string	Optional Fax number of the contact person. Size Range: 10 digits
SigningAuthority	Object	Details of the person authorized to sign the return.
FirstNm	String	First name of the signatory. Size Range: 20
MiddleNm	String	Optional Middle name of the signatory. Size Range: 20
LastNm	String	Last name of the signatory. Size Range: 20
Suffix	String	Optional The suffix of the signatory. Allowed values "Jr", "Sr", "I", "II", "III", "IV", "V", "VI", "VII"
Phone	String	Optional Phone number of the signatory. Size Range: 10 digits
PhoneExtn	String	Optional Phone extension number of the signatory. Size Range: 5
BusinessMemberType	String	Optional Title or role of the signatory. Allowed values "CORPORATESECRETARY", "SECRETARYTREASURER", "PARTNER", "GENERALPARTNER", "LIMITEDPARTNER", "LLCMEMBER", "MANAGINGMEMBER", "MANAGER", "TAXMATTERPARTNER", "PRESIDENT", "VICEPRESIDENT", "CORPORATETREASURER", "TREASURER", "ASSISTANTTREASURER", "CHIEFACCOUNTINGOFFICER", "CHIEFEXECUTIVEOFFICER", "CHIEFFINANCIALOFFICER", "TAXOFFICER", "CHIEFOPERATINGOFFICER", "CORPORATEOFFICER", "EXECUTIVEDIRECTOR", "DIRECTOR", "CHAIRMAN", "EXECUTIVEADMINISTRATOR", "RECEIVER", "PASTOR", "ASSISTANTTORELIGIOUSLEADER", "REVEREND", "PRIEST", "MINISTER", "RABBI", "LEADEROFRELIGIOUSORGANIZATION", "SECRETARY", "DIRECTOROFTAXATION", "DIRECTOROFPERSONNEL", "ADMINISTRATOR", "EXECUTOR", "TRUSTEE", "FIDUCIARY", "OWNER", "SOLEPROPRIETOR", "MEMBER", "SOLEMEMBER", "REPORTINGAGENT"
ReturnData	Object	Identifies the Form M-941.
FormM941	Object	Massachusetts withholding tax returns.
WHIdNum	String	Massachusetts withholding file number. Size Range: ..9
FilingFreq	string	Filing frequency of the Form M-941. Allowed values "ANNUALLY","QUARTERLY","MONTHLY"
Month	string	Select the month for the monthly filing period. Note: Required if the filing frequency is Monthly.
IsFinalReturn	Boolean	When true, indicates that it is a final return.
NumOfEmp	Number	Number of employees. Size Range: 0-9999999
TotTaxWH	Number	Massachusetts income tax withheld from all sources for the filing period. Size Range: 0-99999999.99
IsTaxPaid	Boolean	When true, identifies that the employer has made previous payments.
TaxPaidDetails	Object[]	Identifies the tax paid details.
Date	string	Enter the date the tax was paid. Format: MM/DD/YYYY or MM-DD-YYYY.
Amount	string	Tax paid on the date mentioned. Size Range: 0-99999999.99
TotTaxPaid	Number	Total tax paid for the filing period. Size Range: 0-99999999.99
Overpayment	Number	Previous credits/payments made for the filing period. Size Range: 0-99999999.99
TotPayment	Number	Total payments and credits. Size Range: 0-99999999.99
TotWHDue	Number	Total tax due. Size Range: 0-99999999.99
Penalty	Number	Total penalty amount, if applicable. Size Range: 0-99999999.99
Interest	Number	Total interest due amount, if applicable. Size Range: 0-99999999.99
BalanceDue	Number	Total due amount. Size Range: 0-99999999.99
OverPaymentRecoveryType	string	Gets the overpayment recovery type. Whether to have the state refund the excess amount or apply it to the next return. Allowed values "REFUND", "APPLYTORETURN"
StatePayment	Object	Object that contains information about the payment details.
AccountType	string	Bank account type. Allowed values "CHECKING","SAVING"
BankNm	string	Bank account name of payment. Size Range: 1-30
BankRoutingNum	string	Bank Routing Number of payment. Size Range: 9
BankAccountNum	string	Bank Account Number for payment. Size Range: 1-17
PaymentAmt	Number	Amount to be paid. Size Range: 0-9999999999.99
PaymentReqDate	String	Date when the payment has to be made. Enter the date in the format: MM/DD/YYYY or MM-DD-YYYY. Example: 01/25/2026

Response Body

Field	Type	Description
SubmissionId	Guid	Unique identifier of a submission.
SuccessRecords	object[]	Provides detailed information about the success status of Form M-941 records.
SequenceId	string	A unique reference ID for the submission that can be used to identify a particular record. The Sequence ID will be returned in the response for your reference.
BusinessId	Guid	Unique identifier for the business (payer) generated by TaxBandits.
PayerRef	string	Unique identifier for the business (payer) provided by you.
RecordId	Guid	A unique identifier generated by TaxBandits when a M-941 return is created.
FormType	string	Denotes the type of withholding form M-941.
Status	string	Returns the record status of the return.
StatusTs	string	Returns the date and time when the return was created.
Info	string	Provides additional information about the return.
Errors	object[]	Displays error information related to the state returns of Form M-941.
Id	string	Returns the validation error ID.
Name	string	Name of the validation error.
ErrorRecords	object[]	Provides detailed information about the error status of Form M-941 records.
SequenceId	string	A unique reference ID for the submission that can be used to identify a particular record. The Sequence ID will be returned in the response for your reference.
RecordId	Guid	Unique identifier for the record.
Errors	object[]	Displays detailed error information.
Id	string	Returns the validation error ID.
Name	string	Name of the validation error.
Message	string	Description of the validation error.

Request JSON

Sample 1

{
"StateWHRecords": [
  {
    "SequenceId": "001",
    "ReturnHeader": {
      "TaxYear": "2026",
      "Business": {
        "BusinessId": null,
        "PayerRef": null,
        "IsDefaultBusiness": true,
        "TINDetails": {
          "Format": "PLAIN_TIN",
          "TINType": "EIN",
          "TIN": "45-0052655"
        },
        "IndividualNm": {
          "FirstNm": "James",
          "MiddleNm": "A",
          "LastNm": "Anderson",
          "Suffix": "Jr"
        },
        "BusinessNm": "Snowdaze LLC",
        "NameCtrl": "SNOW",
        "DBADetails": {
          "DBANm": "Iceberg Icecreams",
          "DBARef": "DBA1001",
          "DBAId": null,
          "Address": {
            "Address1": "123 Main St",
            "Address2": "Suite 1001",
            "City": "Rock Hill",
            "ProvinceOrState": "SC",
            "ZipCd": "29730",
            "Country": "US"
          }
        },
        "Address": {
          "Address1": "123 Main St",
          "Address2": "Suite 1001",
          "City": "Rock Hill",
          "ProvinceOrState": "SC",
          "ZipCd": "29730",
          "Country": "US"
        },
        "ContactDetails": {
          "FirstNm": "James",
          "MiddleNm": "A",
          "LastNm": "Anderson",
          "Suffix": "Jr",
          "Phone": "8035551234",
          "PhoneExtn": "101",
          "Email": "contact@snowdaze.com",
          "Fax": "8035555678"
        },
        "BusinessType": "ESTE",
        "SigningAuthority": {
          "FirstNm": "Ambrane",
          "MiddleNm": "A",
          "LastNm": "Cavil",
          "Suffix": "Jr",
          "Phone": "8035551000",
          "PhoneExtn": "111",
          "BusinessMemberType": "ADMINISTRATOR"
        }
      }
    },
    "ReturnData": {
      "FormM941": {
        "WHIdNum": "WTH-74598501-543",
        "FilingFreq": "MONTHLY",
        "Month": "AUG",
        "IsFinalReturn": true,
        "NumOfEmp": "12",
        "TotTaxWH": "20000.00",
        "IsTaxPaid": true,
        "TaxPaidDetails": [
          {
            "Date": "08/15/2026",
            "Amount": "100.00"
          },
          {
            "Date": "08/05/2026",
            "Amount": "60.00"
          }
        ],
        "TotTaxPaid": "160.00",
        "Overpayment": "60.00",
        "TotPayment": "220.00",
        "TotWHDue": "19780.00",
        "Penalty": "100.00",
        "Interest": "120.00",
        "BalanceDue": "20000.00"
      },
      "StatePayment": {
        "AccountType": "CHECKING",
        "BankNm": "IFB",
        "BankRoutingNum": "021000021",
        "BankAccountNum": "9999948932",
        "PaymentAmt": 20000,
        "PaymentReqDate": "11/25/2025"
      }
    }
  }
]
}

Response JSON

Success Response - This is a sample response for successful API requests.

{
  "SubmissionId": "01a0e772-b3b0-7717-bab7-0320f18d81f5",
  "SuccessRecords": [
      {
          "SequenceId": "001",
          "BusinessId": "b53ced19-671e-4ef6-9d86-0de3ebb6abc0",
          "PayerRef": null,
          "RecordId": "01a0e772-b506-713b-a83a-245c1fc00777",
          "FormType": "M941",
          "Status": "CREATED",
          "StatusTs": "2026-09-28 05:57:29 -04:00",
          "Info": null,
          "Errors": null
      }
  ],
  "ErrorRecords": null,
  "Errors": null
}

W-9/W-8 Automation

1099 Automation

TIN Matching

W-2 Automation

941/940 Automation

1098-T Automation

ACA Automation

Extension Automation

1042-S Automation

Supported Forms

Gig Software

Payroll Software

Affiliate Software

HOA Software

Reselling Platform

HCM Providers

Property Management

Healthcare Market Research Platforms

Update

Update

Request Body

Response Body

Request JSON​

Response JSON​

Request JSON

Response JSON