# Your API on your own domain

URL: /publish/hosting · Id: `term:host`

> The home Domain of the Startup an API belongs to: every Interface of the API answers there, and every link stays there.

A Host is the home Domain of the Startup an API belongs to: every [Interface](/interfaces) of the API answers there, and every link stays there.

## Parts
A host answers these paths for every API, before any operation.

| Path | Serves |
| --- | --- |
| `/` | The root JSON: the API name, its operations and its other registers. |
| `/mcp` | The MCP server. |
| `/docs` | The docs, in HTML or Markdown. |
| `/openapi.json` | The OpenAPI 3.1 document. |
| `/llms.txt` | The llms.txt file. |
| `/pricing` | The pricing document. |
| `/.well-known` | The agents.json card. |
| `/sdk` | The generated SDK files. |
| `/batch` | The [Batch](/reference/concepts#batch) route. |
| `/dashboard` | The [Dashboard](/reference/concepts#dashboard). |

## Kinds
Each call is kept in one place, by who made it.

| Call | Kept |
| --- | --- |
| A call by a Customer | In the namespace of the Startup that uses the API, with its input, and never with the Startup that serves it. |
| The usage of that call | In the namespace of the Startup that serves the API: the operation, the outcome and the price, never the input or the [Problem](/evidence/errors) detail. |
| A call by no Customer | In the namespace of the Startup that serves the API. |
| A call with a test or dev Key | In the [test twin](/callers/keys#kinds) of the namespace, whose books never post. |

## Checks
- A host serves the API its namespace defines, from that one [Definition](/reference/concepts#definition).
- The API of a Startup answers on its home Domain; another host does not render it.
- A host reads its Definition again at most 30 seconds after a change.
- Every host answers the reserved paths, and no operation takes one.
- Every response carries the cost header and a request id, a miss and an error included.
- When an operation has no posted rate, the host answers 503 for the whole API.

## Guarantees
- **Every link is on the API's host.** Every generated link is built from the origin the request reached.

## Example
```bash title="Every Interface of the Openhours sample answers on its own host"
curl https://openhours.example/openapi.json
curl https://openhours.example/places/pl_4821/hours -H "X-Api-Key: $OPENHOURS_KEY"
```