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

# Billing

> Turn recurring plans and completed work into paid invoices.

Ionic runs subscription schedules, issues renewal invoices, and retries failed
renewals. For one-off work, create an invoice and collect payment when it is
ready. Your application decides who has access and reacts to
[billing events](/webhooks/overview).

## Start here

<CardGroup cols={2}>
  <Card title="Sell a recurring plan" icon="arrows-rotate" href="/guides/subscriptions">
    Create a subscription and follow it through trials, renewals, and
    cancellations.
  </Card>

  <Card title="Invoice a customer" icon="file-invoice" href="/guides/invoices">
    Add the work to a draft, finalize it, and collect from a saved card or
    hosted payment page.
  </Card>
</CardGroup>

Subscriptions and invoices use [customers](/guides/customers) and saved payment
methods from [Payments](/payments/overview). Subscription items use recurring
[catalog prices](/guides/catalog).

## Manage the billing lifecycle

| You want to | Start with |
| - | - |
| Let a buyer sign up on a hosted page | [Checkout in subscription mode](/guides/checkout#selling-a-subscription) |
| Grant access according to the customer's plan | [Subscription entitlement](/guides/subscriptions#check-entitlement) |
| Change a plan or schedule its cancellation | [Subscription management](/guides/subscriptions) |
| Correct a paid invoice and record the adjustment | [Credit notes](/guides/credit-notes) |
| Verify renewals, retries, and cancellations before launch | [Test clocks](/guides/test-clocks) |

Ionic sends [subscription](/webhooks/events#subscriptions),
[invoice](/webhooks/events#invoices), and
[credit note](/webhooks/events#credit-notes) events. Use them to keep access and
your customer records current.

For billing that belongs to connected merchants, see
[Connect billing](/guides/connect-billing). A platform creates and changes a
merchant's plans, subscriptions, invoices, and credit notes with its platform
key, and the merchant can bill with its own keys or in the Dashboard.

## Availability

* Subscription items use recurring catalog prices.
* Test clocks run in [test mode](/concepts/key-concepts#test-mode-and-live-mode).
* Hosted invoice pages show Apple Pay once Ionic enables it on your account.

## API reference

| Resource | Endpoints |
| - | - |
| Subscriptions | [Create](/api-reference/subscriptions/create-a-subscription), [list](/api-reference/subscriptions/list-subscriptions), [retrieve](/api-reference/subscriptions/retrieve-a-subscription), [check entitlement](/api-reference/subscriptions/check-subscription-entitlement), [cancel](/api-reference/subscriptions/cancel-a-subscription), [resume](/api-reference/subscriptions/resume-a-subscription), [update items](/api-reference/subscriptions/update-subscription-items), [update collection method](/api-reference/subscriptions/update-collection-method), [update default payment method](/api-reference/subscriptions/update-default-payment-method), [update metadata](/api-reference/subscriptions/update-metadata) |
| Invoices | [Create](/api-reference/invoices/create-an-invoice), [list](/api-reference/invoices/list-invoices), [retrieve](/api-reference/invoices/retrieve-an-invoice), [add a line](/api-reference/invoices/add-a-line-to-a-draft-invoice), [remove a line](/api-reference/invoices/remove-a-line-from-a-draft-invoice), [finalize](/api-reference/invoices/finalize-an-invoice), [collect payment](/api-reference/invoices/collect-payment-on-an-invoice), [update payment method](/api-reference/invoices/update-an-invoices-payment-method), [void](/api-reference/invoices/void-an-invoice), [mark uncollectible](/api-reference/invoices/mark-an-invoice-uncollectible), [list payment attempts](/api-reference/invoices/list-an-invoices-payment-attempts), [download PDF](/api-reference/invoices/download-an-invoice-pdf) |
| Invoice items | [Create](/api-reference/invoice-items/create-an-invoice-item), [retrieve](/api-reference/invoice-items/retrieve-an-invoice-item), [update](/api-reference/invoice-items/update-an-invoice-item), [delete](/api-reference/invoice-items/delete-an-invoice-item) |
| Credit notes | [Preview](/api-reference/credit-notes/preview-a-credit-note), [create](/api-reference/credit-notes/create-a-credit-note), [list](/api-reference/credit-notes/list-credit-notes), [retrieve](/api-reference/credit-notes/retrieve-a-credit-note), [void](/api-reference/credit-notes/void-a-credit-note), [download PDF](/api-reference/credit-notes/download-a-credit-note-as-pdf) |
| Test clocks | [Create](/api-reference/test-clocks/create-a-test-clock), [retrieve](/api-reference/test-clocks/retrieve-a-test-clock), [advance](/api-reference/test-clocks/advance-a-test-clock), [arm the next collection outcome](/api-reference/test-clocks/arm-the-next-subscription-collection-outcome) |


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