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Version: 2.0.0

Overview

Maryland employers and payers subject to income tax withholding must file withholding returns with the Comptroller of Maryland based on their assigned filing frequency.

The TaxBandits API supports Maryland Form MW506 for employer income tax withholding reporting.

Forms supported​

FormTypeFiling frequencyDue date
MW506WithholdingMonthly / Quarterly / AnnualBased on assigned filing frequency

Key compliance notes​

  • Withholding reporting. Employers and payers subject to Maryland income tax withholding must file Form MW506 (Employer's Return of Income Tax Withheld) and remit the tax withheld to the Comptroller of Maryland.
  • Filing frequency. The filing frequency may be monthly, quarterly, annual, or periodic/accelerated, depending on the amount of Maryland tax withheld.
  • Quarterly filing. Quarterly returns are due on the 15th day of the month following the end of the quarter.
  • Monthly filing. Monthly returns are due on the 15th day of the following month.
  • Electronic filing. TaxBandits enables employers to prepare and electronically transmit Maryland withholding reports through the Public API.
  • Zero returns. A withholding return is required even when no tax was withheld for the reporting period.

API endpoints​

For Maryland withholding reporting, the state-specific methods — Create, Update, and Get — are available for the MW506 form. The utility methods — List, Delete, Transmit, RequestPdfUrls, and Status — are shared across State and Withholding reporting.

MW506 (Maryland Withholding)​

  • Create — Create a new Maryland withholding report.
  • Update — Update an MW506 report that was created but not yet transmitted.
  • Get — Retrieve the details of a created MW506 report.

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

All 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 our 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.