# Hydda One API

> Build integrations with Hydda One: authenticate an Application, then sell bookable resources, connect an ERP or a signing service.

## Docs

- [Hydda One API](https://docs.hydda.one/): Build integrations with Hydda One. Authenticate an Application, then sell bookable resources, connect an ERP or connect a signing service.

## Guides

- [Introduction](https://docs.hydda.one/guides): The two hosts, what an Application is, and the first call every integration makes.
- [Authentication](https://docs.hydda.one/guides/authentication): Get an access token from the token endpoint, with client credentials or as an installed connector.
- [Roles](https://docs.hydda.one/guides/roles): Which role a token needs for each part of the API, and where the role must be granted.
- [Errors](https://docs.hydda.one/guides/errors): The problem details body every failure returns, how to read it, and every error code.

### Surfaces

- [Booking](https://docs.hydda.one/guides/surfaces/booking): Sell an organization's bookable resources on its own website, as requests that an operator approves.
- [Billing](https://docs.hydda.one/guides/surfaces/billing): Deliver an organization's approved invoices through your ERP or invoicing platform, and report each outcome back.
- [Signing](https://docs.hydda.one/guides/surfaces/signing): Send an organization's contracts out for electronic signature through your signing provider, and report each outcome back.
- [Integrations](https://docs.hydda.one/guides/surfaces/integrations): Read the configurations an organization saved for your installed app, connect them, and report whether each one works.

## Reference

- [Hydda One API](https://docs.hydda.one/reference)

### Billing

- [List approved invoices ready to send](https://docs.hydda.one/reference/billing/list-send-queue)
- [List deleted invoices you may still hold](https://docs.hydda.one/reference/billing/list-invoice-withdrawal-queue)
- [List invoice proposals awaiting verification](https://docs.hydda.one/reference/billing/list-verification-queue)
- [Pass an invoice proposal](https://docs.hydda.one/reference/billing/pass-proposal)
- [Reject an invoice proposal](https://docs.hydda.one/reference/billing/reject-proposal)
- [Report a deleted invoice discarded](https://docs.hydda.one/reference/billing/report-withdrawal-discarded)
- [Report a payment by your own invoice id](https://docs.hydda.one/reference/billing/report-payment-by-external-reference)
- [Report a payment on an invoice](https://docs.hydda.one/reference/billing/report-payment)
- [Report a payment reversal by your own invoice id](https://docs.hydda.one/reference/billing/report-payment-reversed-by-external-reference)
- [Report a payment taken back](https://docs.hydda.one/reference/billing/report-payment-reversed)
- [Report a write-off on an invoice](https://docs.hydda.one/reference/billing/report-write-off)
- [Report an invoice sent](https://docs.hydda.one/reference/billing/report-sent)
- [Report an invoice that could not be sent](https://docs.hydda.one/reference/billing/report-invoice-failed)

### Booking

- [Get a booking request](https://docs.hydda.one/reference/booking/get-external-booking-request)
- [Get one resource the Application may sell](https://docs.hydda.one/reference/booking/get-externally-bookable-resource)
- [List the extras a resource sells](https://docs.hydda.one/reference/booking/list-external-add-on-products)
- [List the resources the Application may sell](https://docs.hydda.one/reference/booking/list-externally-bookable-resources)
- [Look up a company by organisation number](https://docs.hydda.one/reference/booking/read-external-company-status)
- [Price a booking before requesting it](https://docs.hydda.one/reference/booking/preview-external-booking-request)
- [Read a resource's free time](https://docs.hydda.one/reference/booking/read-external-availability)
- [Request a booking for a guest](https://docs.hydda.one/reference/booking/request-external-booking)

### Integrations

- [List your installation's configurations](https://docs.hydda.one/reference/integrations/list-own-integration-configurations)
- [Redeem a connection reference from your setup address](https://docs.hydda.one/reference/integrations/redeem-connection-reference)
- [Report a configuration as failed](https://docs.hydda.one/reference/integrations/report-configuration-failed)
- [Report a configuration as ready](https://docs.hydda.one/reference/integrations/report-configuration-ready)

### Operational contexts

- [List the operational contexts the token can act in](https://docs.hydda.one/reference/operational-contexts/list-my-operational-contexts)

### Signing

- [Get an upload address for the signed PDF](https://docs.hydda.one/reference/signing/request-signed-document-upload)
- [List contracts waiting to be sent for signature](https://docs.hydda.one/reference/signing/list-signing-queue)
- [List signing attempts the operator wants withdrawn](https://docs.hydda.one/reference/signing/list-signing-withdrawal-queue)
- [Report that a party declined to sign](https://docs.hydda.one/reference/signing/report-declined)
- [Report that every party signed](https://docs.hydda.one/reference/signing/report-signed)
- [Report that the document could not be created](https://docs.hydda.one/reference/signing/report-signing-failed)
- [Report that the document expired unsigned](https://docs.hydda.one/reference/signing/report-expired)
- [Report that the document is out for signature](https://docs.hydda.one/reference/signing/report-started)
- [Report that the document was cancelled](https://docs.hydda.one/reference/signing/report-withdrawn)

## Agent resources

- [llms-full.txt](https://docs.hydda.one/llms-full.txt): The full Markdown of every page in one file.
- [Page Markdown](https://docs.hydda.one/index.md): Append `.md` to any page URL to fetch that page as raw Markdown.
- [JSON API](https://docs.hydda.one/api/docs/pages.json): Page index of the JSON docs API; each entry links the page's JSON and Markdown forms. Described by the OpenAPI document at https://docs.hydda.one/openapi.json.
- [API catalog](https://docs.hydda.one/.well-known/api-catalog): RFC 9727 linkset of the APIs documented here.
- [AI catalog](https://docs.hydda.one/.well-known/ai-catalog.json): ARD manifest of the agent-facing resources on this site (MCP server, skills, APIs).
- [agent-readability.json](https://docs.hydda.one/agent-readability.json): Manifest of every agent-facing artifact on this site.
- [Sitemap](https://docs.hydda.one/sitemap.xml): Every indexable page URL with its last-modified date.