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Version: 2.0.0

Overview

Colorado employers who withhold Colorado income tax must file withholding returns and remit the tax to the Colorado Department of Revenue (CDOR). Separately, employers subject to unemployment insurance must file quarterly wage and premium reports with the Colorado Department of Labor and Employment (CDLE).

For the TaxBandits Public API, the Colorado UI implementation includes UITR-1 (Quarterly Report of Wages Paid and Premiums Owed) and UITR-1A (Report of Individual Employee's Wages).

The TaxBandits API supports automating UITR-1/UITR-1A for unemployment insurance reporting.

Forms supported​

FormTypeFiling frequencyDue date
Form UITR-1UIQuarterlyLast day of the month following the quarter end
Form UITR-1AUI Wage ReportQuarterlyLast day of the month following the quarter end

Form UITR-1 — Colorado UI Premiums Report​

Form UITR-1 is the Quarterly Report of Wages Paid and Premiums Owed. It reports the employer's quarterly wages, excess wages, and unemployment insurance premiums owed.

The report is due on the last day of the month following the quarter end.

Quarterly due dates are:

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

Form UITR-1A — Individual Employee Wage Report​

Form UITR-1A is the Report of Individual Employee's Wages. It provides employee-level wage information associated with the quarterly unemployment insurance filing.

Colorado requires the UITR-1A wage report to be filed quarterly along with the UI reporting obligation. The wage report is due on the same quarterly schedule as UITR-1.

Key compliance notes​

  • Withholding frequency depends on liability. Colorado determines whether an employer files quarterly, monthly, or weekly based on the amount of withholding tax reported.
  • Annual information reporting. Employers must file applicable W-2s with Colorado by January 31 following the tax year.
  • Quarterly UI reporting. Employers subject to Colorado unemployment insurance must file the quarterly premium and wage reports.
  • Employee-level wage reporting. UITR-1A contains individual employee wage information.
  • UI reports have a common quarterly deadline. UITR-1 and UITR-1A are due by the last day of the month following the quarter.
  • Electronic filing. Colorado requires electronic filing in certain circumstances, including applicable UI wage reporting and employers meeting the state's withholding electronic-filing requirements.

API endpoints​

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

Form UITR-1 / UITR-1A (Colorado UI)​

  • Create — Create a new Colorado quarterly UI wage and premium report.
  • Update — Update a UI report that was created but not yet transmitted.
  • Get — Retrieve the details of a created Colorado UI 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 Colorado 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.