openapi: 3.1.0
info:
  title: BILL v3 Authentication Invoices API
  description: 'REST API providing access to BILL''s Accounts Payable, Accounts Receivable,

    and Spend & Expense capabilities — bills, invoices, vendors, customers,

    payments, funding accounts, organizations, webhooks, and authentication

    workflows.


    Best-effort OpenAPI reconstruction from BILL''s public developer portal at

    https://developer.bill.com/docs/home. Authoritative reference and Postman

    collection live under https://developer.bill.com/reference and

    https://developer.bill.com/llms.txt.

    '
  version: 3.0.0
  contact:
    name: BILL Developer Portal
    url: https://developer.bill.com/docs/home
  license:
    name: Proprietary
servers:
- url: https://gateway.prod.bill.com/connect/v3
  description: BILL production gateway (Connect v3)
- url: https://gateway.stage.bill.com/connect/v3
  description: BILL sandbox gateway (Connect v3)
- url: https://api.bill.com/v3
  description: BILL production API
- url: https://api-sandbox.bill.com/v3
  description: BILL sandbox API
security:
- sessionAuth: []
tags:
- name: Invoices
paths:
  /invoices:
    get:
      tags:
      - Invoices
      summary: List invoices
      operationId: listInvoices
      responses:
        '200':
          description: Invoices.
    post:
      tags:
      - Invoices
      summary: Create an invoice
      operationId: createInvoice
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/InvoiceCreate'
      responses:
        '201':
          description: Created invoice.
  /invoices/{invoiceId}:
    parameters:
    - name: invoiceId
      in: path
      required: true
      schema:
        type: string
    get:
      tags:
      - Invoices
      summary: Retrieve an invoice
      operationId: getInvoice
      responses:
        '200':
          description: Invoice.
    patch:
      tags:
      - Invoices
      summary: Update an invoice
      operationId: updateInvoice
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/InvoiceCreate'
      responses:
        '200':
          description: Updated invoice.
  /invoices/{invoiceId}/send:
    parameters:
    - name: invoiceId
      in: path
      required: true
      schema:
        type: string
    post:
      tags:
      - Invoices
      summary: Send an invoice to the customer
      operationId: sendInvoice
      responses:
        '200':
          description: Sent.
components:
  schemas:
    InvoiceCreate:
      type: object
      required:
      - customerId
      - invoiceNumber
      - invoiceDate
      - dueDate
      - invoiceLineItems
      properties:
        customerId:
          type: string
        invoiceNumber:
          type: string
        invoiceDate:
          type: string
          format: date
        dueDate:
          type: string
          format: date
        glPostingDate:
          type: string
          format: date
        salesTax:
          type: number
          format: double
        invoiceLineItems:
          type: array
          items:
            type: object
            properties:
              itemId:
                type: string
              quantity:
                type: number
              amount:
                type: number
                format: double
              price:
                type: number
                format: double
              description:
                type: string
  securitySchemes:
    sessionAuth:
      type: apiKey
      in: header
      name: sessionId
      description: 'Session identifier obtained from `POST /login`. Expires after 35 minutes

        of inactivity. A `devKey` (developer key) is also required on requests

        and is sent alongside `sessionId` in the appropriate header per BILL''s

        official reference.

        '