Forms index

MOCK SERVER, does not file with the IRS. Form notes describe what the mock models; they are not tax advice and not a statement of what the IRS will accept.

Form	In the mock?	Doc
941 Employer's Quarterly Federal Tax Return	Yes	Form 941
941-X Adjusted 941 / claim for refund	Yes (no separate page; summary in the tools reference and error catalog)
944 Employer's Annual Federal Tax Return	Yes	Form 944
7004 Business extension	Yes	Form 7004
943	Planned, not implemented
940, 945, 1120-S, 8868	NOT AVAILABLE to this company. The mock does not expose them: formType accepts only the implemented forms, list_supported_forms reports them as "not available to us", and a 7004 with returnType: "1120-S" is refused (SCHEMA error). Agents must not try to work around this (for example by filing 1120-S extension data under another return type) and must tell the human the form is unavailable.

IRS sources were retrieved on 2026-10-23 from irs.gov. Where a fact could not be confirmed on the page fetched, it is marked UNVERIFIED. Always have a human confirm dates and eligibility against the current IRS instructions.