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

# API reference

> Find the Guile API domain you need and authenticate before you call it

The Guile API is split into domains. Pick the domain that matches the job, then
call that group's operations.

## What you do first

1. Start with the [quickstart](/quickstart) if you need an anonymous token.
2. Put a bearer token in the `Authorization` header for signed-in calls.
3. Open the domain overview for the job, then the operation you need.

| Job                                                | Domain                                                   |
| -------------------------------------------------- | -------------------------------------------------------- |
| Prove who is calling                               | [Authentication](/api-reference/Authentication/overview) |
| Book, authorize, capture, cancel                   | [Appointments](/api-reference/Appointments/overview)     |
| Take a card on a terminal                          | [Payments](/api-reference/Payments/overview)             |
| Quote customer or barber fees                      | [Fees](/api-reference/Fees/overview)                     |
| Cash out processor balance to a bank or debit card | [Payouts](/api-reference/Payouts/overview)               |
| Request or decide a refund                         | [Refunds](/api-reference/Refunds/overview)               |
| Manage a shop and its money settings               | [Businesses](/api-reference/Businesses/overview)         |

Many calls need a real session. Move from the quickstart to the
[authentication overview](/api-reference/Authentication/overview) when OTP or
passkeys replace the anonymous token.

## When a call fails

Failures come back as problem documents. Open the `type` link for the cause, the
fix, and whether retrying is safe. See [problem types](/api-reference/problems).

## Related paths

* [Artifacts](/api-reference/artifacts): OpenAPI and Postman downloads
* [Idempotency keys](/api-reference/idempotency): safe retries on money writes
* [Date ranges](/api-reference/date-ranges): filter list calls by day
* [Problem types](/api-reference/problems): recover from a failed call