This data is moving to FiscalData.Treasury.gov where it is available for download in multiple machine-readable formats with complete metadata!
Monthly Receipts, Outlays, and Deficit or Surplus, Fiscal Years 1981-2021:
These files contain the monthly receipts/outlays and deficit/surplus of the United States published in Table 1 of the Monthly Treasury Statement, for fiscal years 1981-2021. The figures reflect backdated adjustments and may be amended (monthly) based on agency reporting.
Quarterly Distributed Offsetting Receipts by Department Report
Budget Summary with Adjusted Differences Report - August 2021