[Beta] — staging only. This endpoint is currently available on the staging environment for integration testing; it is not yet enabled in production.

Submits up to 5000 SII tax reports in one request as a batch.

Processing is always asynchronous. This endpoint validates only the envelope (a tax_reports array within the size limit) and returns 202 Accepted immediately with a batch_id and a status_url; the per-record build, validation and ledger attach run in a background job. Use GET /accounts/{account}/tax_report_batches/{id} (the returned status_url) to poll for results, or subscribe to the sii_batch.finished webhook event to be notified when the batch finishes.

Each record is validated independently in the job — a failure on one record (bad book_type, XSD-invalid XML, unsupported type) does not abort the batch; it appears as a per-record error in the batch status. Non-SII type values are rejected per-record with the unsupported_type code.

For the same request shape on a single record, use POST /tax_reports instead.