> ## Documentation Index
> Fetch the complete documentation index at: https://replyke-feat-push-rich-payload-fields.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Add Host

> Grant a user host privileges on an event (host-only)

Adds a user to the event's `hostIds`. **Host-only** — the caller must already be a host (service/master keys bypass this). The operation is idempotent (adding an existing host is a no-op) and takes a row-level lock to serialize concurrent host changes.

There is no requirement that the target be a space member or invitee — any user can be made a host.

## Path Parameters

<ParamField path="eventId" type="string" required>
  UUID of the event.
</ParamField>

## Body Parameters

<ParamField body="userId" type="string" required>
  The user to grant host on the event.
</ParamField>

## Response

Returns the updated [Event](/data-models/event) with the new `hostIds`.

## Error Responses

<AccordionGroup>
  <Accordion title="Not Found — 404">
    ```json theme={null}
    { "error": "Event not found", "code": "event/not-found" }
    ```
  </Accordion>

  <Accordion title="Forbidden (not a host) — 403">
    ```json theme={null}
    { "error": "Only a host of this event may manage its hosts.", "code": "event/forbidden" }
    ```
  </Accordion>
</AccordionGroup>

See also: [useAddHost](/hooks/events/use-add-host)