export const metadata = {
    title: 'Server Metadata',
    description: 'Metadata about a Versia instance, such as capabilities and endpoints.',
}

# Server Metadata

Contains metadata about a Versia instance, such as capabilities and endpoints. {{ className: 'lead' }}

<Note>
    This entity is only used as part of [Server Discovery](/federation/discovery#server-discovery), and not as part of federation.
</Note>

## The `null` Author

On all entities that have an `author` field, the `author` can be `null` to represent the instance itself as the author (like ActivityPub's Server Actors). In this case, the instance's public key should be used to verify the entity.

## Entity Definition

<Row>
    <Col>
        <Properties>
            <Property name="id" type="null">
                This entity does not have an ID.
            </Property>
            <Property name="uri" type="null">
                This entity does not have a URI.
            </Property>
            <Property name="name" type="string" required={true}>
                Friendly name of the instance, for humans.
            </Property>
            <Property name="software" type="Software" required={true}>
                Information about the software running the instance.

                ```typescript
                type Software = {
                    name: string;
                    version: string;
                }
                ```

                - `name`: Name of the software.
                - `version`: Version of the software. Should use [SemVer](https://semver.org/).
            </Property>
            <Property name="compatibility" type="Compatibility" required={true}>
                Information about the compatibility of the instance.

                ```typescript
                type Compatibility = {
                    versions: string[];
                    extensions: string[];
                }
                ```

                - `versions`: Supported Versia Protocol versions.
                  - Versions marked as "Working Draft X" are represented as `0.X`.
                - `extensions`: Supported extensions.
            </Property>
            <Property name="description" type="string" required={false}>
                Long description of the instance, for humans. Should be around 100-200 words.
            </Property>
            <Property name="host" type="string" required={true}>
                Hostname of the instance. Includes the port if it is not the default (i.e. `443` for HTTPS).
            </Property>
            <Property name="shared_inbox" type="URI" required={false}>
                URI to the instance's shared inbox, if supported.
            </Property>
            <Property name="public_key" type="PublicKey" required={true}>
                Public key of the instance.

                ```typescript
                type PublicKey = {
                    algorithm: string;
                    key: string;
                }
                ```
                
                - `algorithm`: Algorithm used for the public key. Can only be `ed25519` for now.
                - `key`: Public key of the instance. Must follow the [Versia Public Key](/signatures) format.
            </Property>
            <Property name="moderators" type="URI" required={false}>
                URI to [Collection](/structures/collection) of instance moderators.

                <Note>
                    This is for human consumption (such as moderator contact), not for any kind of protocol authorization.
                </Note>
            </Property>
            <Property name="admins" type="URI" required={false}>
                URI to [Collection](/structures/collection) of instance administrators.

                <Note>
                    This is for human consumption (such as admin contact), not for any kind of protocol authorization.
                </Note>
            </Property>
            <Property name="logo" type="ContentFormat" required={false} typeLink="/structures/content-format">
                Logo of the instance. Must be an image format (`image/*`).
            </Property>
            <Property name="banner" type="ContentFormat" required={false} typeLink="/structures/content-format">
                Banner of the instance. Must be an image format (`image/*`).
            </Property>
        </Properties>
    </Col>

    <Col sticky>

    ```jsonc {{ 'title': 'InstanceMetadata' }}
    {
        "type": "InstanceMetadata",
        "name": "Jim's Jolly Jimjams",
        "software": {
            "name": "Versia Server",
            "version": "1.2.0-beta.3"
        },
        "compatibility": {
            "versions": [
                "0.3.0",
                "0.4.0"
            ],
            "extensions": [
                "pub.versia:reactions",
                "pub.versia:polls",
                "pub.versia:reports"
            ]
        },
        "description": "Server for Jim's Jolly Jimjams, a social network for fans of Jimjams.",
        "host": "social.jimjams.com",
        "shared_inbox": "https://social.jimjams.com/inbox",
        "moderators": "https://social.jimjams.com/moderators",
        "admins": "https://social.jimjams.com/admins",
        "logo": {
            "image/png": {
                "content": "https://social.jimjams.com/files/logo.png"
            },
            "image/webp": {
                "content": "https://social.jimjams.com/files/logo.webp"
            }
        },
        "public_key": {
            "algorithm": "ed25519",
            "key": "MCowBQYDK2VwAyEA9zhEMtQZetRl4QrLcz99i7jOa6ZVjX7aLfRUsMuKByI="
        },
        "banner": null,
        "extensions": {
            "example.extension:monthly_active_users": 1000
        }
    }
    ```

    </Col>
</Row>