Reviewing a client's Making Tax Digital Income Tax year and sending their tax return to HMRC. The review is thirty or more HMRC requests behind one call — every income source's obligations, reporting setup, held position and year-end work, all their other income, losses, liability adjustments, HMRC's calculation, and the declaration with whatever is standing in the way — so it is slow the first time a year is opened and fast afterwards. What it reports as standing in the way is advice rather than a gate: HMRC hold the real rules and a practice that disagrees may proceed. The one exception is the declaration, which HMRC require the software itself to enforce. Behind its own permission, separate from quarterly updates, because HMRC allow a supporting agent to file the second and not the first. This filing is not idempotent: a submission whose outcome is unknown is settled by reconciling it against HMRC's own record, never by sending again.

Send Tax Return

POST /tenants/{tenant}/clients/{client}/mtd/tax-return/{taxYear}/submit

Sends the client's tax return to HMRC against the calculation named in the request. Refused unless the declaration has been read and agreed, and refused when the declaration wording has changed since it was displayed. This filing is not idempotent: HMRC create something that cannot be re-stated, so a submission whose outcome is unknown stays in flight and is settled by reconciling it — never by sending again. HMRC take up to an hour to show the year as fulfilled, so say 'sent' rather than 'filed' until they do. Costs one filing credit, reserved before the call and released if it definitively did not land.

Parameters

Name	Type	Description
tenant*	path string	The Tenant.Code
The Tenant.Code
client*	path string
taxYear*	path string

Request Body*

SubmitMtdTaxReturnRequest

{
  "calculationId": "string",
  "declarationType": "Unknown",
  "isDeclarationAgreed": false,
  "declarationVersion": "string"
}

Responses

200 OK

MtdTaxReturnSubmissionDto

400 Bad Request

401 Unauthorized – Invalid or missing API key

404 Not Found