Version: 1.7.3

Create

Use this endpoint to create Form IL 3/40 (Illinois Quarterly Tax and Wage Report) for an employer (payer), reporting quarterly wages, taxable wages, and unemployment insurance (UI) contributions due, along with required employee wage details for the corresponding quarter.

Note:

Form IL 3/40 must be filed every quarter, even if no wages were paid.

Updated wage base limits for Illinois Form UI-3/40:

Tax year	Wage Base Limit per employee
2025	$13,916
2026	$14,250

POST StateFilings/ILUI/Create

Run in Postman

Request Body

Field	Type	Description
StateUIRecords	Object[]	Object to identify the records.
SequenceId	String	A unique identifier for this record. Size Range: ..50
ReturnHeader	Object	Contains information about the Business details.
TaxYr	string	The tax year for which the Form IL 3/40 is to be filed. Allowed values "2025","2026"
Qtr	string	The quarter for which the Form IL 3/40 is to be filed. Allowed values "Q1", "Q2", "Q3", "Q4"
Business	Object	Object to identify the business details.
BusinessId	Guid	Optional Use the unique identifier provided in the response from the Business CREATE endpoint.
BusinessNm	string	Name of the business. Size Range: ..75
TradeNm	string	Optional Name under which the business operates. Size Range: ..75
IsEIN	Boolean	When true, identifies the business with an EIN.
EINorSSN	string	When IsEIN is true, use the Employer Identification Number (EIN) Note: IsEIN should always be set to true, as EIN is the only allowed TIN type for state payroll forms. Size Range: 9-11
Email	string	Optional Email address of the business. Size Range: ..100
ContactNm	string	Optional Name of the person who can be contacted by the State Agency. Size Range: ..27
Phone	string	Optional Phone number of the business. Size Range: 10
PhoneExtn	string	Optional Extension of the business phone number. Size Range: ..5
Fax	string	Optional Fax number of the business. Size Range: 10
BusinessType	string	Type of business. Size Range: 4 Allowed values "ESTE", "PART", "CORP", "EORG", "SPRO"
SigningAuthority	object	Details of the person who is authorized to sign the return.
Name	string	Name of the signing authority. Size Range: ..35
Phone	string	Phone number of the signing authority. Size Range: 10
BusinessMemberType	string	Business title of the signing authority Size Range: 5..29 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"
KindOfEmployer	string	Optional Identifies the kind of employer. Allowed values "FEDERALGOVT", "STATEORLOCAL501C", "NONGOVT501C", "STATEORLOCALNON501C", "NONEAPPLY"
KindOfPayer	string	Optional Identifies the kind of payer. Allowed values "REGULAR941", "REGULAR944", "AGRICULTURAL943", "HOUSEHOLD", "MILITARY", "MEDICAREQUALGOVEM", "RAILROADFORMCT1"
IsBusinessTerminated	Boolean	When true, indicates that the business is terminated.
IsForeign	Object	When true, indicates that the business has a foreign address.
USAddress	object	If IsForeign is false, pass the US address of the business.
Address1	string	Employer/Payer's US address (street or post office box of that locality). Size Range: ..46
Address2	string	Optional Employer/Payer's suite or apartment. Size Range: ..46
City	string	Employer/Payer's city. Size Range: ..50
State	string	Employer/Payer's state code. Refer to static values. Size Range: 2 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"
ZipCd	string	Employer/Payer's zip code. Size Range: 5..10
ForeignAddress	Object	If IsForeign is true, pass the foreign address of the business.
Address1	string	Employer/Payer's foreign address (street address or post office box of that locality). Size Range: ..50
Address2	string	Optional Employer/Payer's suite or apartment. Size Range: ..50
City	string	Employer/Payer's city. Size Range: ..50
ProvinceOrStateNm	string	Employer/Payer's province or state name. Size Range: ..50
Country	string	Employer/Payer's country. Size Range: 2 Allowed values "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"
PostalCd	string	Employer/Payer's postal code. Size Range: ..16
ReturnData	Object	Contains the return information.
FormIL340	Object	Identifies the Form IL 3/40 data.
BusinessClass	String	Type of business calssification Allowed values "SOLE_PROPRIETOR", "S_CORPORATION", "C_CORPORATION", "PARTNERSHIP","TRUST_OR_ESTATE", "EXEMPT_ORGANIZATION", "STATE_AND_LOCAL_GOVERNMENT"
IsNoEmpOrBusienssClosed	Boolean	If true identifies that the business has ceased operations or had no employees during that quarter.
IsNoWageReported	Boolean	When true, indicates that no wage is reported in this quarter
UIIdNum	String	Employer's Illinois Unemployment Account Number Size Range: 8 digits Sample format: 99999999
EmployerTaxType	String	Employment tax type Allowed values "TAXABLE_EMPLOYER", "REIMBURSABLE_EMPLOYER"
TotWagesAmt	Number	Total wages paid for the quarter. Size Range: 0-99999999999.99
TotExcessWageAmt	Number	Total excess wages paid for the quarter. Size Range: 0-99999999999.99
TotTaxableWages	Number	Total taxable wages paid for all employees in the quarter that is subject to Illinois Unemployment Insurance. Size Range: 0-99999999.99
TaxRate	Number	Tax rate for the quarter. Size Range: 1-100
ContribAmt	Number	Contribution amount for the quarter Size Range: 0-99999999.99
Interest	Number	Optional Interest due for the quarter (2% per month after the due date). Size Range: 0-99999999.99
PenaltyLateFiling	Number	OptionalLate filing penalty for the quarter. Size Range: 0-99999999.99
UnderPayment	Number	OptionalLate filing penalty for the quarter. Size Range: 0-99999999.99
OverPayment	Number	OptionalLate filing penalty for the quarter. Size Range: 0-99999999.99
BalanceDue	Number	Total remittance due for the quarter. Size Range: 0-99999999.99
NumOfEmployees	Object	Identifies the total number of employees for the quarter.
Month1TotEmployees	string	Total number of employees in month 1 of the quarter. Size Range: 0-9999999
Month2TotEmployees	string	Total number of employees in month 2 of the quarter. Size Range: 0-9999999
Month3TotEmployees	string	Total number of employees in month 3 of the quarter. Size Range: 0-9999999
EmployeeDetails	Object	Object to identify the employee details.
EmpSequenceId	string	A unique number to identify this record. Size Range: 1-10
EmployeeId	Guid	OptionalA unique ID generated by TaxBandits after the return is created Size Range: ..10
EmployeeId	Guid	OptionalA unique ID generated by TaxBandits after the return is created and returned in the response.
EmpRef	string	A unique identifier of the employee. Size Range: 1-50
SSN	string	Employee's Social Security Number (SSN). Size Range: 9-11
FirstNm	string	Employee's first name. Size Range: 1-15
MiddleNm	string	OptionalEmployee's middle name. Size Range: 1-15
LastNm	string	Employee's last name. Size Range: 1-20
Suffix	string	OptionalEmployee's suffix. Allowed values "Jr", "Sr", "I", "II", "III", "IV", "V", "VI", "VII","Jr", "Sr", "I", "II", "III", "IV", "V", "VI", "VII"
GrossWagesAmt	Number	Total gross wages reported for the quarter. Size Range: 0-99999999999.99
TaxableAmt	Number	Total taxable wages from the gross wages paid to the employee Size Range: ..99999999.99 Note: The taxable wage base limit varies by tax year. Refer to the updated base limits provided above for each tax year.
ExcessAmt	Number	Total excess wages for the quarter. Size Range: ..99999999.99

Response Body

Field	Type	Description
SubmissionId	Guid	Unique identifier for a submission.
SuccessRecords	object[]	Provides detailed information about the success status of Form IL 3/40 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 Form IL 3/40 return is created.
FormType	string	Type of form.
Status	string	Returns the record status.
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 IL 3/40.
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 IL 3/40 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

Create IL 3/40 return for each quarter of the tax year

{
  "StateUIRecords": [
      {
          "SequenceId": "001",
          "ReturnHeader": {
              "TaxYr": "2026",
              "Qtr": "Q1",
              "Business": {
                  "BusinessId": null,
                  "BusinessNm": "Snowdaze LLC",
                  "TradeNm": "Mayfill Tech",
                  "IsEIN": true,
                  "EINorSSN": "74-6572341",
                  "Email": "james@sample.com",
                  "ContactNm": "John",
                  "Phone": "7894561231",
                  "IsForeign": false,
                  "BusinessType": "SLGOV",
                  "SigningAuthority": {
                      "Name": "James Smith",
                      "Phone": "9934567890",
                      "BusinessMemberType": "DIRECTOR"
                  },
                  "USAddress": {
                      "Address1": "12 Main st",
                      "Address2": "CC avenue",
                      "City": "Rock Hill",
                      "State": "SC",
                      "ZipCd": "29730"
                  },
                  "ForeignAddress": {
                      "Address1": null,
                      "Address2": null,
                      "City": null,
                      "ProvinceOrStateNm": null,
                      "Country": null,
                      "PostalCd": null
                  }
              }
          },
          "ReturnData": {
              "FormIL340": {
                  "IsNoEmpOrBusienssClosed": false,
                  "IsNoWageReported": false,
                  "UIIdNum": 8934577,
                  "EmployerTaxType": "TAXABLE_EMPLOYER",
                  "TotWagesAmt": 50000,
                  "TotExcessWageAmt": 49600,
                  "TotTaxableWages": 400,
                  "TaxRate": 0.5,
                  "ContribAmt": 2,
                  "Interest": 45455,
                  "PenaltyLateFiling": 355,
                  "Underpayment": 355,
                  "Overpayment": 355888,
                  "BalanceDue": -309721,
                  "NumOfEmployees": {
                      "Month1TotEmployees": 10,
                      "Month2TotEmployees": 0,
                      "Month3TotEmployees": 0
                  },
                  "EmployeeDetails": [
                      {
                          "EmpSequenceId": "01",
                          "EmployeeId": null,
                          "EmpRef": null,
                          "SSN": "001456924",
                          "FirstNm": "John",
                          "MiddleNm": "A",
                          "LastNm": "Smith",
                          "Suffix": "Sr",
                          "GrossWagesAmt": 50000,
                          "TaxableAmt": 400,
                          "ExcessAmt": 49600,
                          "USAddress": {
                              "Address1": "12 Main St",
                              "Address2": "CC avenue",
                              "City": "Rock Hill",
                              "State": "SC",
                              "ZipCd": "29730"
                          }
                      }
                  ]
              }
          }
      }
  ]
}

Response JSON

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

{
  "StatusCode": "200",
  "StatusName": "Ok",
  "StatusMessage": "Successful API call",
  "SubmissionId": "019cb36d-0258-7044-948f-a3dbbef22fa1",
  "SuccessRecords": [
      {
          "SequenceId": "001",
          "BusinessId": "c8198997-6f20-439d-bac3-239226af2e7d",
          "PayerRef": null,
          "RecordId": "019cb36d-119e-713a-b0af-fee59838641e",
          "FormType": "IL340",
          "EmployeeData": [
              {
                  "EmployeeId": "05f634a9-d5d8-4498-ae8e-55ec7d27bc3b",
                  "EmpRef": "Pe011204121"
              }
          ],
          "Status": "CREATED",
          "StatusTs": "2026-03-03 06:19:55 -05:00",
          "Info": null,
          "Errors": null
      }
  ],
  "ErrorRecords": null,
  "Errors": null
}

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Create

Updated wage base limits for Illinois Form UI-3/40:​

Request Body

Response Body

Request JSON​

Response JSON​

Updated wage base limits for Illinois Form UI-3/40:

Request JSON

Response JSON