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

# Check domain availability

> Check whether a host can be connected by the API-key owner inside Biqli.

Check whether a host is available to connect **inside Biqli**. This is not a
registrar lookup and does not tell you whether the domain can be purchased.

Requires **Custom domains: Write** (`custom_domains.create`) and a plan that
includes custom domains.

```bash theme={null}
curl --get 'https://biq.li/api/v1/domain/availability' \
  --header 'Authorization: Bearer biqli_your_workspace_api_key' \
  --header 'Accept: application/json' \
  --data-urlencode 'host=go.example.com'
```

## Responses

A host not claimed in Biqli:

```json theme={null}
{
  "host": "go.example.com",
  "available": true,
  "reason": "available",
  "domain_id": null,
  "status": "success"
}
```

A host already owned by the API-key user remains available for attachment to
this workspace:

```json theme={null}
{
  "host": "go.example.com",
  "available": true,
  "reason": "already_owned",
  "domain_id": "biq_dom_01M18D4A8QRJY5G6K3N2W7X9TZ",
  "status": "success"
}
```

If the host is already attached to this workspace, `reason` is
`already_connected`. This remains safe when another workspace member originally
created the shared workspace domain.

A claim owned by another Biqli account returns `200 OK` with
`available: false`, `reason: domain_taken`, and a null `domain_id`. It does not
reveal who owns the domain. Invalid, unsafe, blacklisted, or application hosts
return `422 validation_error`.

Because availability can change between checking and creating, always handle
`409 domain_taken` from [Create a domain](/docs/api-reference/domains/create).

## Shared API behavior

Authentication is workspace-scoped; see [Authentication](/docs/api-reference/authentication). Errors use the standard envelope and request IDs described in [Errors](/docs/api-reference/errors), and requests are subject to [Rate limits](/docs/api-reference/rate-limits).


## OpenAPI

````yaml GET /v1/domain/availability
openapi: 3.1.0
info:
  title: Biqli API
  version: 1.0.0
  description: Workspace-scoped REST API for Biqli.
servers:
  - url: https://biq.li/api
security:
  - bearerAuth: []
paths:
  /v1/domain/availability:
    get:
      tags:
        - Domains
      summary: Check domain availability
      description: >-
        Checks whether a host can be connected by the API-key owner inside
        Biqli. This is not registrar availability. Requires
        custom_domains.create.
      operationId: domain.availability
      parameters:
        - name: host
          in: query
          required: true
          schema:
            type: string
            maxLength: 100
          example: go.example.com
      responses:
        '200':
          description: Availability checked successfully.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/DomainAvailabilityResponse'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '403':
          $ref: '#/components/responses/Forbidden'
        '422':
          $ref: '#/components/responses/UnprocessableEntity'
        '429':
          $ref: '#/components/responses/RateLimited'
        '500':
          $ref: '#/components/responses/InternalError'
components:
  schemas:
    DomainAvailabilityResponse:
      type: object
      additionalProperties: false
      required:
        - host
        - available
        - reason
        - domain_id
        - status
      properties:
        host:
          type: string
        available:
          type: boolean
        reason:
          type: string
          enum:
            - available
            - already_connected
            - already_owned
            - domain_taken
        domain_id:
          type:
            - string
            - 'null'
          pattern: ^biq_dom_[0-9A-HJKMNP-TV-Z]{26}$
        status:
          type: string
          const: success
    ApiError:
      type: object
      required:
        - error
        - request_id
      properties:
        error:
          type: object
          required:
            - code
            - message
          properties:
            code:
              type: string
              enum:
                - invalid_token
                - insufficient_scope
                - upgrade_required
                - quota_exceeded
                - resource_not_found
                - domain_taken
                - alias_taken
                - external_id_taken
                - folder_name_taken
                - tag_name_taken
                - pixel_name_taken
                - biolink_name_taken
                - method_not_allowed
                - url_blocked
                - dns_verification_failed
                - validation_error
                - rate_limit_exceeded
                - internal_server_error
            message:
              type: string
            details:
              type: object
              additionalProperties: true
        request_id:
          type: string
          description: Request identifier to include when contacting support.
  responses:
    Unauthorized:
      $ref: '#/components/responses/ApiErrorResponse'
      description: The workspace API key is missing, invalid, or revoked.
    Forbidden:
      $ref: '#/components/responses/ApiErrorResponse'
      description: >-
        The key lacks a required scope, the workspace must upgrade, or its quota
        is exhausted.
    UnprocessableEntity:
      $ref: '#/components/responses/ApiErrorResponse'
      description: >-
        The payload is invalid, a destination was blocked, or domain DNS
        verification is not ready.
    RateLimited:
      description: The workspace exceeded its plan's API rate limit.
      headers:
        RateLimit-Policy:
          description: Current IETF HTTPAPI quota policy as a structured field.
          schema:
            type: string
            example: '"workspace-api";q=1000;w=60'
        RateLimit:
          description: Current IETF HTTPAPI service limit as a structured field.
          schema:
            type: string
            example: '"workspace-api";r=0;t=17'
        Retry-After:
          description: Seconds to wait before retrying the request.
          schema:
            type: integer
            minimum: 0
            example: 17
        X-RateLimit-Limit:
          description: Legacy maximum request count for the current window.
          schema:
            type: integer
            minimum: 1
            example: 1000
        X-RateLimit-Remaining:
          description: Legacy remaining request count.
          schema:
            type: integer
            minimum: 0
            example: 0
        X-RateLimit-Reset:
          description: Legacy reset time as a UTC Unix timestamp.
          schema:
            type: integer
            format: int64
            example: 1788126519
        X-Biq-Request-Id:
          description: Request identifier for support and tracing.
          schema:
            type: string
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ApiError'
    InternalError:
      $ref: '#/components/responses/ApiErrorResponse'
      description: The request failed unexpectedly.
    ApiErrorResponse:
      description: API error.
      headers:
        X-Biq-Request-Id:
          description: Request identifier for support and tracing.
          schema:
            type: string
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ApiError'
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer
      bearerFormat: Workspace API key
      description: A workspace API key beginning with biqli_.

````