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POST
/
v1
/
billing.preview_multi_attach
Typescript (SDK)
import { Autumn } from 'autumn-js'

const autumn = new Autumn()

const result = await autumn.billing.previewMultiAttach({
  customerId: "cus_123",
  plans: [
    {
      planId: "pro_plan",
    },
    {
      planId: "addon_seats",
      featureQuantities: [
        {
          featureId: "seats",
          quantity: 5,
        },
      ],
    },
  ],
});
{
  "customerId": "charles",
  "lineItems": [
    {
      "display_name": "Pro seed",
      "description": "Pro seed - Base Price (from 18 Feb 2026 to 18 Mar 2026)",
      "subtotal": 20,
      "total": 20,
      "discounts": []
    }
  ],
  "subtotal": 20,
  "total": 20,
  "currency": "usd"
}

​
Body Parameters

​
Response

{
  "customerId": "charles",
  "lineItems": [
    {
      "display_name": "Pro seed",
      "description": "Pro seed - Base Price (from 18 Feb 2026 to 18 Mar 2026)",
      "subtotal": 20,
      "total": 20,
      "discounts": []
    }
  ],
  "subtotal": 20,
  "total": 20,
  "currency": "usd"
}

Authorizations

​
Authorization
string
header
required

Bearer authentication header of the form Bearer <token>, where <token> is your auth token.

Headers

​
x-api-version
string
default:2.1
required

Body

application/json
​
customer_id
string
required

The ID of the customer to attach the plans to.

​
plans
object[]
required

The list of plans to attach to the customer.

Minimum array length: 1
​
entity_id
string

The ID of the entity to attach the plans to.

​
free_trial
FreeTrialParams · object

Free trial configuration applied to all plans. Pass an object to set a custom trial, or null to remove any trial.

​
invoice_mode
object

Invoice mode creates a draft or open invoice and sends it to the customer, instead of charging their card immediately.

​
discounts
AttachDiscount · object[]

List of discounts to apply. Each discount can be an Autumn reward ID, Stripe coupon ID, or Stripe promotion code.

​
success_url
string

URL to redirect to after successful checkout.

​
checkout_session_params
object

Additional parameters to pass into the creation of the Stripe checkout session.

​
redirect_mode
enum<string>
default:if_required

Controls when to return a checkout URL. 'always' returns a URL even if payment succeeds, 'if_required' only when payment action is needed, 'never' disables redirects.

Available options:
always,
if_required,
never
​
new_billing_subscription
boolean

Only applicable when the customer has an existing Stripe subscription. If true, creates a new separate subscription instead of merging into the existing one.

​
customer_data
CustomerData · object

Customer details to set when creating a customer

​
entity_data
object

Response

200 - application/json

OK

​
customer_id
string
required

The ID of the customer.

​
line_items
object[]
required

List of line items for the current billing period.

​
subtotal
number
required

The total amount in cents before discounts for the current billing period.

​
total
number
required

The final amount in cents after discounts for the current billing period.

​
currency
string
required

The three-letter ISO currency code (e.g., 'usd').

​
incoming
object[]
required

Products or subscription changes being added or updated.

​
outgoing
object[]
required

Products or subscription changes being removed or ended.

​
next_cycle
object

Preview of the next billing cycle, if applicable. This shows what the customer will be charged in subsequent cycles.

​
expand
string[]

Expand the response with additional data.