> ## Documentation Index
> Fetch the complete documentation index at: https://docs.bolta.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Email-Approved Reverse Issuance

> A workflow where, after a reverse issuance request, the supplier approves via an email link.

When the platform requests reverse issuance, **Bolta automatically sends an approval-request email to the supplier's manager email address**, and the supplier approves through the email link.

## Workflow

<Steps>
  <Step title="Register the supplier" icon="code">
    Call the [Register Supplier API](/api-reference/supplier/register-supplier) to register the supplier's information with Bolta. Save the `supplierKey` returned after registration.
  </Step>

  <Step title="Request reverse issuance" icon="code">
    Call the [Request Reverse Issuance API](/api-reference/reverse-issuance/request-reverse-issuance). Pass the supplier's `supplierKey` in the `Supplier-Key` header. Bolta automatically sends an approval-request email to the supplier's manager email address.
  </Step>

  <Step title="Send the approval-request email" icon="mail">
    Bolta sends an approval-request email to the supplier's manager email address. The supplier clicks the link in the email and approves on Bolta.
  </Step>

  <Step title="Supplier approval" icon="user-check">
    The supplier accesses Bolta through the email link and approves the tax invoice.
  </Step>

  <Step title="Receive the issuance-complete webhook" icon="zap">
    Once approval is complete, a [webhook](/en/api-introduction/webhook-events) sends a notification that includes `taxInvoiceUrl`.
  </Step>

  <Step title="Retrieve the tax invoice (optional)" icon="search">
    Check the issuance result with the [Retrieve Tax Invoice API](/api-reference/tax-invoice/retrieve-tax-invoice).
  </Step>
</Steps>

## Canceling a reverse issuance request

Before approval, you can cancel the reverse issuance request by calling the [Cancel Reverse Issuance Request API](/api-reference/reverse-issuance/cancel-reverse-issuance-request).

* On a successful cancellation, the response is returned with HTTP 200.
* If the request has already been approved, canceled, or issued, an error is returned.

<Warning>
  **Approval is not possible past the issuance deadline**

  If the issuance deadline has passed, the supplier cannot approve. Update the date and submit the request again.
</Warning>

## When this fits

* When it is difficult to obtain the supplier's certificate in advance
* When the supplier prefers a simple email-based approval
* When the platform wants to delegate approval to Bolta rather than building its own approval UI

## Difference from simple-approval reverse issuance

|                      | Email approval                    | [Simple approval](/en/api-introduction/usecase-reverse-simple) |
| -------------------- | --------------------------------- | -------------------------------------------------------------- |
| Approval method      | Email link sent by Bolta          | Approval URL issued by the platform                            |
| Certificate required | Not required                      | Required                                                       |
| Who approves         | Supplier, directly from the email | Supplier, within the platform                                  |