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

# Add line item

> Adds a line item to an order that has not been invoiced.



## OpenAPI

````yaml /api-reference/openapi.yaml post /orders/{id}/line_items
openapi: 3.0.3
info:
  title: Streamlined API
  description: >
    Access customers, customer applications, customer groups, products, payouts,
    invoices, transactions, and deposit links programmatically through this API,
    and receive webhooks when deposit links change. All requests must be
    authenticated with an API key.
  version: 1.6.0
  license:
    name: Proprietary
    url: https://streamlinedpayments.com/terms
servers:
  - url: https://api.staging.streamlinedpayments.com/api/v1
    description: Sandbox
  - url: https://api.streamlinedpayments.com/api/v1
    description: Production
security:
  - AppIdAuth: []
    ApiKeyAuth: []
tags:
  - name: Customers
    description: Create, update and delete the businesses you sell to.
  - name: Customer applications
    description: >-
      List the applications your customers submit, and approve them. Approving
      can also set net terms and export the customer to Shopify. See [Approve
      customer applications](/guides/customer-applications).
  - name: Customer groups
    description: >-
      Organize customers into groups and manage who's in each one. A group can
      be linked to a Shopify B2B company.
  - name: Customer files
    description: Upload and manage files attached to a customer.
  - name: Customer addresses
    description: Manage a customer's addresses and choose their default billing address.
  - name: Orders
    description: Create orders, add and remove line items, and schedule them.
  - name: Invoices
    description: Create invoices from orders, then list, look up and update them.
  - name: Transactions
    description: List transactions and look one up.
  - name: Payouts
    description: List payouts, including pending ones, and look one up.
  - name: Products
    description: >-
      Create and update the products and services you sell, import them in bulk,
      and merge duplicates.
  - name: Deposit links
    description: Collect money from a customer before an invoice exists.
  - name: Webhooks
    description: >-
      Register HTTPS endpoints to receive events when something changes. See
      [Webhooks](/guides/webhooks) for signatures, retries and delivery
      guarantees.
paths:
  /orders/{id}/line_items:
    post:
      tags:
        - Orders
      summary: Add line item
      description: Adds a line item to an order that has not been invoiced.
      operationId: addLineItem
      parameters:
        - name: id
          in: path
          description: The UUID of the order to add a line item to
          required: true
          schema:
            type: string
            format: uuid
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              properties:
                line_item:
                  type: object
                  required:
                    - description
                    - quantity
                    - net_amount
                  properties:
                    description:
                      type: string
                      description: Description of the line item
                    quantity:
                      type: number
                      format: float
                      description: Quantity of the item
                    net_amount:
                      type: integer
                      description: Net amount in cents
                    discount_bps:
                      type: integer
                      description: Discount in basis points
      responses:
        '201':
          description: Line item created successfully
          content:
            application/json:
              schema:
                type: object
                properties:
                  line_item:
                    type: object
                    properties:
                      uuid:
                        type: string
                        format: uuid
                      description:
                        type: string
                      quantity:
                        type: string
                      net_amount:
                        type: integer
                      discount_bps:
                        type: integer
                  order:
                    type: object
                    properties:
                      uuid:
                        type: string
                        format: uuid
                      total_amount:
                        type: integer
        '400':
          description: Bad request
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '404':
          description: Order not found
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
              example:
                error: Order not found
        '422':
          description: Unprocessable entity
          content:
            application/json:
              schema:
                type: object
                properties:
                  errors:
                    type: array
                    items:
                      type: string
                example:
                  errors:
                    - Cannot add line items to an invoiced order
components:
  schemas:
    Error:
      type: object
      properties:
        error:
          type: string
        message:
          type: string
  responses:
    Unauthorized:
      description: Authentication failed
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
          examples:
            AuthenticationRequired:
              value:
                error: Authentication required
                message: >-
                  API endpoint requires authentication. Please provide valid
                  X-App-Id and X-Api-Key headers.
            InvalidCredentials:
              value:
                error: Invalid credentials
                message: >-
                  The provided API credentials are invalid. Please check your
                  X-App-Id and X-Api-Key values.
  securitySchemes:
    AppIdAuth:
      type: apiKey
      in: header
      name: X-App-Id
      description: App ID for authentication
    ApiKeyAuth:
      type: apiKey
      in: header
      name: X-Api-Key
      description: API Key for authentication

````

This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.