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

# Make a hub the default one

> Marks one of your own hubs as the default one — the hub used when a campaign is created without a `knowledgeHubId` — and clears the flag on every other hub you own. A teammate's hub is readable through `GET /business/knowledge-hubs/{hubId}` but cannot be made your default and answers 403 `KNOWLEDGE_HUB_OWNER_ONLY`. The response echoes the request; read the hub back with `GET /business/knowledge-hubs/{hubId}` to confirm.

Errors:
- `403` `KNOWLEDGE_HUB_OWNER_ONLY` — The hub belongs to a teammate; you can read it, but only its owner can make it their default hub.
- `404` `KNOWLEDGE_HUB_NOT_FOUND` — No hub with that id, it was deleted, or it belongs to another team.
- `422` `VALIDATION_FAILED` — hubId missing or not a 24-character hex id.
- `429` `RATE_LIMITED` — More than 30 knowledge-hub/campaign requests in a minute (or 1000 in a day). Knowledge hubs share the campaigns bucket.

Requires one of the following token scopes: campaigns.



## OpenAPI

````yaml /openapi.json post /business/knowledge-hubs/default
openapi: 3.1.0
info:
  title: Fuse Business API
  version: 1.0.0
  description: >-
    External API for lists, campaigns, prospect search and contacts.
    Authenticate with your API token as HTTP Basic. All paths are under /api/v1.
servers:
  - url: https://api.tryfuse.ai/api/v1
    description: Production
security:
  - basicAuth: []
tags:
  - name: Lists
  - name: Custom columns
  - name: Smart columns
  - name: Exports
  - name: Campaigns
  - name: Knowledge hubs
  - name: Analytics
  - name: Website intent
  - name: Account
  - name: Prospect search
  - name: Campaign steps
  - name: Scheduled sends
  - name: Campaign templates
  - name: Agents
  - name: Research
  - name: Company search
  - name: Saved searches
  - name: Folders
  - name: Contacts
paths:
  /business/knowledge-hubs/default:
    post:
      tags:
        - Knowledge hubs
      summary: Make a hub the default one
      description: >-
        Marks one of your own hubs as the default one — the hub used when a
        campaign is created without a `knowledgeHubId` — and clears the flag on
        every other hub you own. A teammate's hub is readable through `GET
        /business/knowledge-hubs/{hubId}` but cannot be made your default and
        answers 403 `KNOWLEDGE_HUB_OWNER_ONLY`. The response echoes the request;
        read the hub back with `GET /business/knowledge-hubs/{hubId}` to
        confirm.


        Errors:

        - `403` `KNOWLEDGE_HUB_OWNER_ONLY` — The hub belongs to a teammate; you
        can read it, but only its owner can make it their default hub.

        - `404` `KNOWLEDGE_HUB_NOT_FOUND` — No hub with that id, it was deleted,
        or it belongs to another team.

        - `422` `VALIDATION_FAILED` — hubId missing or not a 24-character hex
        id.

        - `429` `RATE_LIMITED` — More than 30 knowledge-hub/campaign requests in
        a minute (or 1000 in a day). Knowledge hubs share the campaigns bucket.


        Requires one of the following token scopes: campaigns.
      operationId: setDefaultKnowledgeHub
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              properties:
                hubId:
                  type: string
                  description: >-
                    24-character hex id of the hub to make the default; every
                    other hub loses the flag.
              required:
                - hubId
      responses:
        '200':
          description: Success
          headers:
            RateLimit-Limit:
              schema:
                type: integer
              description: Requests permitted in the current window.
            RateLimit-Remaining:
              schema:
                type: integer
              description: Requests remaining in the current window.
            RateLimit-Reset:
              schema:
                type: integer
              description: Seconds until the current window resets.
          content:
            application/json:
              schema:
                type: object
                required:
                  - knowledgeHub
                properties:
                  knowledgeHub:
                    type: object
                    required:
                      - id
                      - isDefault
                    properties:
                      id:
                        type: string
                      isDefault:
                        type: boolean
                        enum:
                          - true
              example:
                knowledgeHub:
                  id: 68a1f8509c41d20014b3ee41
                  isDefault: true
        '400':
          description: Error
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
        '401':
          description: Error
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
        '402':
          description: Error
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
        '403':
          description: Error
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
        '404':
          description: Error
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
        '409':
          description: Error
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
        '422':
          description: Error
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
        '429':
          description: Error
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
        '500':
          description: Error
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
      security:
        - basicAuth: []
components:
  schemas:
    Error:
      type: object
      properties:
        error:
          type: object
          properties:
            code:
              type: string
            message:
              type: string
            param:
              type:
                - string
                - 'null'
            doc_url:
              type:
                - string
                - 'null'
            request_id:
              type:
                - string
                - 'null'
          required:
            - code
            - message
      required:
        - error
  securitySchemes:
    basicAuth:
      type: http
      scheme: basic
      description: >-
        Your API token (`af_…`) as the Basic-auth username, with an empty
        password.

````