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Version: 2.0.0

Overview

Connecticut employers who withhold state income tax must file withholding returns with the Connecticut Department of Revenue Services (DRS). Separately, employers subject to Connecticut unemployment insurance must file quarterly unemployment tax and wage reports with the Connecticut Department of Labor (CTDOL).

The TaxBandits Public API supports automating Form CT-941 for Connecticut withholding and Form UC-2 for unemployment insurance reporting. Connecticut's FSET program specifically identifies CT-941, UC-2, and UC-5A as its employment-tax returns.

Forms supported​

FormTypeFiling frequencyDue date
Form CT-941WithholdingQuarterlyLast day of the month following the quarter end
Form UC-2UIQuarterlyLast day of the month following the quarter end

Form CT-941 — Connecticut Quarterly Withholding​

Form CT-941 (Connecticut Quarterly Reconciliation of Withholding) is used by employers to report and reconcile Connecticut income tax withheld from employee wages. Quarterly filers must file the return by the last day of the month following the quarter.

The quarterly due dates are:

  • Q1 (January–March): April 30
  • Q2 (April–June): July 31
  • Q3 (July–September): October 31
  • Q4 (October–December): January 31

Connecticut requires withholding returns and payments to be filed electronically.

Form UC-2 — Employer Contribution Return​

Form UC-2 (Employer Contribution Return) is the Connecticut unemployment insurance contribution return. It reports the employer's unemployment insurance tax information, including gross wages, taxable wages, and contributions due.

Employers subject to Connecticut unemployment insurance must file quarterly UI tax and wage reports electronically.

Key compliance notes​

  • Quarterly withholding filing. Employers registered for Connecticut withholding generally must file Form CT-941 each quarter. Seasonal employers may have different filing requirements if approved by DRS.
  • Annual reconciliation. Form CT-W3 and the applicable W-2 information are due January 31.
  • Quarterly UI reporting. Employers subject to Connecticut unemployment insurance must file the UC-2 and UC-5A quarterly.
  • Zero-wage UI filing. A liable employer operating without employees must still file a no-wage return each quarter. Failure to do so can result in a $25 late fee.
  • Electronic filing. Connecticut requires employers to file and pay unemployment contributions electronically.
  • Withholding payments. Connecticut requires withholding tax payments to be made electronically, subject to applicable waiver rules.
  • W-2 electronic filing. Employers filing 25 or more Connecticut W-2s must file them electronically unless granted a waiver.

API endpoints​

For these forms, the state-specific methods — Create, Update, and Get — differ by form because each has its own field structure. The utility methods — List, Delete, Transmit, RequestPdfUrls, and Status — are shared across State Withholding and UI reporting.

Form CT-941 — Connecticut Withholding​

  • Create — Create a new CT-941 quarterly withholding return.
  • Update — Update a CT-941 return that was created but not yet transmitted.
  • Get — Retrieve the details of a created CT-941 return.

Form UC-2 / UC-5A — Connecticut UI​

  • Create — Create a new Connecticut quarterly unemployment insurance report.
  • Update — Update a UC-2/UC-5A report that was created but not yet transmitted.
  • Get — Retrieve the details of a created UC-2/UC-5A report.

Common endpoints: For the remaining methods — List, Status, Transmit, RequestPdfUrls, and Delete — refer to the common endpoints shared across State Withholding and UI reporting.

State New Hire Reporting​

TaxBandits also supports Connecticut New Hire Reporting through the common State New Hire Reporting API for reporting newly hired and rehired employees.

All TaxBandits API endpoints require an OAuth 2.0 access token. Call the Auth method and pass the token as a Bearer token in the request header.

Testing & notifications​

Before filing, you can simulate the entire verification flow in the TaxBandits Sandbox environment without submitting real data to state agencies.

As an alternative to polling the Status endpoint, you can configure a webhook for the Status Payroll Filings Status Change event type to receive automated status updates.