Tax Documents

Decibyl issues two kinds of tax document: a receipt voucher when you top up, and a tax invoice for usage. Each is available as JSON and as a PDF, and each is emailed to you automatically when it is issued.

Documents are statements about a moment

A document is frozen at the point of issue. It carries its own snapshot of both parties — your billing details and Decibyl’s — and its own line items, rather than pointing at whatever your account looks like today.

This matters more than it sounds. If you change your registered address or GSTIN next month, documents already issued keep the details they were issued with. That is what makes them usable as evidence: a receipt is a statement about a transaction that happened, not a view that quietly rewrites itself.

The PDF renders from those same frozen fields, so it can never disagree with the JSON for the same document.

Endpoints

GET /api/v1/billing/documents
GET /api/v1/billing/documents/{document_id}
GET /api/v1/billing/documents/{document_id}/pdf

The PDF response is application/pdf, sent as an attachment with the document number as the filename. Forward slashes in the number are replaced with hyphens so the filename is valid on every platform.

All three are scoped to your currently selected organization — a document id from another account returns 404, not 403, so ids cannot be probed.

Automatic email on issue

When a document is issued, Decibyl emails the PDF to the billing address on the document.

The send is asynchronous and best-effort, by design. Issuing the document is the part that must not fail — it is evidence that a payment or a month of usage happened — so it commits in its own transaction and the email is queued afterwards. A mail server being slow or unreachable can never roll back a receipt voucher.

Three things cause no email to be sent, none of which affects the document itself:

Condition	Behaviour
No mail server configured on the deployment	Nothing is sent, silently
No billing email on the document’s customer snapshot	Nothing is sent; logged with the document number
Document not found when the job runs	Logged as a warning; no retry storm

In all three cases the document exists and is downloadable through the API. If you were expecting an email and didn’t get one, check that a billing email is set on your account — and note that the address used is the one captured on the document at issue, not the address on your account now.

Duplicate sends are collapsed: the job id is derived from the document id, so issuing-then-enqueueing twice results in one email rather than two.

If an email does not arrive

The document itself is never blocked by mail. If a send fails, generation and download work exactly as normal and only the email is skipped — so the invoice or voucher is always available from Billing, and you can re-send it from there.