> ## Documentation Index
> Fetch the complete documentation index at: https://docs.sync2books.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Void an invoice



## OpenAPI

````yaml /openapi/accounting.json post /invoices/{invoiceId}/void
openapi: 3.1.0
info:
  title: Sync2Books Accounting API
  version: 1.0.0
  description: >-
    Write categorized expenses, bills, invoices, and payments to your customers'
    accounting systems (QuickBooks Online, Xero, Sage, Dynamics 365 Business
    Central, Odoo) through one API.


    This is a **separate product** from the [Sync2Books Compliance API
    (eTIMS)](/etims-overview) — use this one to sync bookkeeping data to an
    accounting system; use that one for KRA tax compliance in Kenya. A company
    can use either, both, or neither.


    Writes are **asynchronous**: most create endpoints queue the record and
    return a `syncBatchId` you confirm via the [Sync](#tag/Sync) endpoints — see
    [The sync model](/concepts/sync-model).
servers:
  - url: https://api.sync2books.com
    description: Production
  - url: https://sandbox-api.sync2books.com
    description: Sandbox (coming soon)
security:
  - ApiKeyAuth: []
tags:
  - name: Companies
    description: Your customers — the entities you sync data for.
  - name: Expenses
    description: Categorized expenses, receipts, and payments.
  - name: Bills
    description: Accounts-payable documents (money you owe suppliers).
  - name: Invoices
    description: Accounts-receivable documents (money customers owe you).
  - name: Bill Payments
    description: Payments applied against one or more bills.
  - name: Attachments
    description: Receipts and supporting documents on a synced transaction.
  - name: Sync
    description: Track and retry the asynchronous batches every write creates.
paths:
  /invoices/{invoiceId}/void:
    post:
      tags:
        - Invoices
      summary: Void an invoice
      parameters:
        - name: invoiceId
          in: path
          required: true
          schema:
            type: string
      responses:
        '200':
          description: Voided
        '400':
          description: Not yet synced to the accounting system
components:
  securitySchemes:
    ApiKeyAuth:
      type: apiKey
      in: header
      name: X-API-Key
      description: >-
        Your application's API key (`sk_development_…` or `sk_production_…`). An
        optional `X-Signature` / `X-Timestamp` HMAC pair may additionally be
        sent for stronger security — see
        [Authentication](/concepts/authentication).

````

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