# Advance invoice schedules

> For the complete machine-readable documentation index, see [llms.txt](https://apidocs.chargebee.com/llms.txt).


The invoice for a subscription in Chargebee is generated at the time of subscription renewal. Invoices can also be [generated in advance](https://www.chargebee.com/docs/advance-invoices.html) for an upcoming renewal or set of renewals. With Advance Invoicing Schedules, you can set up a plan for when such advance invoices are generated for the lifetime of the subscription. This helps you:

-   Set up a contract with your customers so that they can be notified of their payment schedules in advance.
-   Allow customers who make offline payments to be alerted about their upcoming dues well ahead of actual subscription renewals.
-   Prevent post-renewal unpaid usage of your services by customers.

Advance invoices can be scheduled in two ways:

#### Specific Dates Schedule[](#specific-dates-schedule)

Advance invoices for a subscription can be scheduled to be generated on specific [dates](/docs/api/advance_invoice_schedules/advance_invoice_schedule-object#specific_dates_schedule_date) in the future. You must specify the [number of billing cycles](/docs/api/advance_invoice_schedules/advance_invoice_schedule-object#specific_dates_schedule_terms_to_charge) to be invoiced on each date. A maximum of 5 dates can be specified.

#### Fixed Interval Schedule[](#fixed-interval-schedule)

Advance invoices can be scheduled to be generated at fixed intervals of time, where each interval spans the same number of billing cycles of the subscription. The invoice for each interval is generated a specified number of days ([`days_before_interval`](/docs/api/advance_invoice_schedules/advance_invoice_schedule-object#fixed_interval_schedule_days_before_renewal)) before the start of the interval. You can configure the schedule to end on a certain date or after a specified number of advance invoices have been generated.

The start date of the first interval depends on the number of days remaining from current time till the next renewal of the subscription. If this is more than `days_before_interval`, the interval begins at the next renewal. On the other hand, if the number of days remaining before the next renewal is less than `days_before_interval`, the first interval begins at the renewal following the next.

## Sample Advance invoice schedule

```json
{
  "id": "__test__KyVkmQSCX2vRK2t",
  "object": "advance_invoice_schedule",
  "schedule_type": "specific_dates",
  "specific_dates_schedule": {
    "date": 1518339706,
    "object": "specific_dates_schedule",
    "terms_to_charge": 2
  }
}
```

## Advance invoice schedules attributes

## Input Parameters

- `id` (required, string, max chars=40)
  System-generated and immutable unique Id for the `advance_invoice_schedule` .

- `schedule_type` (optional, enumerated string)
  The type of advance invoice or advance invoicing schedule.
  Possible enum values:
    - `fixed_intervals`
      The advance charges occur at [fixed intervals of time](/docs/api/advance_invoice_schedules/advance_invoice_schedule-object#fixed_interval_schedule_terms_to_charge) .
    - `specific_dates`
      The advance charges occur on specific dates. For each date, [a fixed number of billing cycles](/docs/api/advance_invoice_schedules/advance_invoice_schedule-object#specific_dates_schedule_terms_to_charge) is charged for. There can be up to 5 dates configured.

- `fixed_interval_schedule` (optional, fixed_interval_schedule)
  When the `schedule_type` is `fixed_intervals` , this object gives further details of the schedule.
  - `end_schedule_on` (optional, enumerated string)
    Specifies when the schedule should end.
    Possible enum values:
      - `after_number_of_intervals`
        Advance invoices are generated a `specified number of times`
      - `specific_date`
        End the advance invoicing schedule on a `specific date` .
      - `subscription_end`
        Advance invoices are generated for as long as the subscription is active.
  - `number_of_occurrences` (optional, integer, min=1)
    The number of advance invoices to generate. The schedule is created such that the total number of billing cycles in the schedule does not exceed the [`remaining_billing_cycles`](/docs/api/subscriptions/subscription-object#remaining_billing_cycles) of the subscription. This parameter is applicable only when [`fixed_interval_schedule[end_schedule_on]`](/docs/api/advance_invoice_schedules/advance_invoice_schedule-object#fixed_interval_schedule_end_schedule_on) = `after_number_of_intervals`
  - `days_before_renewal` (optional, integer, min=1)
    The number of days before each interval that advance invoices are generated.
  - `end_date` (optional, timestamp(UTC) in seconds)
    The date when the schedule should end. Advance invoices are not generated beyond this date. It must be at least 1 day before the start of the last billing cycle of the subscription and also within 5 years from the current date. This parameter is only applicable when [`fixed_interval_schedule[end_schedule_on]`](/docs/api/advance_invoice_schedules/advance_invoice_schedule-object#fixed_interval_schedule_end_schedule_on) = `specific_date` .
  - `created_at` (required, timestamp(UTC) in seconds)
    The date when this advance invoicing schedule was created.
  - `terms_to_charge` (optional, integer, min=1)
    The number of billing cycles in one interval.

- `specific_dates_schedule` (optional, specific_dates_schedule)
  The advance charges occur on specific dates. For each date, [a fixed number of billing cycles](/docs/api/advance_invoice_schedules/advance_invoice_schedule-object#specific_dates_schedule_terms_to_charge) is charged for. There can be up to 5 dates configured.
  - `terms_to_charge` (optional, integer)
    The number of billing cycles to charge for, on the date specified. Applicable only when [`schedule_type`](/docs/api/advance_invoice_schedules/advance_invoice_schedule-object#schedule_type) is specific\_dates.
  - `date` (optional, timestamp(UTC) in seconds)
    The unique id of the member of the advance\_invoice\_schedule array which corresponds to the specific\_dates\_schedule that you intend to modify. Only applicable when [`schedule_type`](/docs/api/advance_invoice_schedules/advance_invoice_schedule-object#schedule_type) is `specific_dates` .
  - `created_at` (required, timestamp(UTC) in seconds)
    The date when this advance invoicing schedule was created.