# Generate Thumbnail Upload URL

Generates a pre-signed URL for securely uploading a thumbnail image. The link expires after 10 minutes.

Considerations:
- Uploaded images are not optimized by the server; please upload images pre-optimized for web use.
- Each uploaded file receives a unique thumbnailId for reference within your application, but the file name in the bucket is derived from this ID, ensuring no conflicts with existing files.

Endpoint: POST /v4/thumbnails/upload-url
Version: 2026-03-27
Security: ZephrHmacHttp

## Request fields (application/json):

  - `fileName` (string)
    The name of the file. Unique file names are recommended but not enforced; the system generates a unique ID for each upload.
    Example: "unique-thumbnail.jpg"

  - `contentType` (string)
    The MIME type of the file. Supported MIME types include image/jpeg, image/png, and image/gif.
    Example: "image/jpeg"

## Response 200 fields (application/json):

  - `id` (string)
    A unique identifier for the uploaded thumbnail, used for referencing in the application.

  - `uploadUrl` (string)
    The pre-signed URL for uploading the thumbnail.

## Response 400 fields (application/json):

  - `error` (string)

## Response 401 fields (application/json):

  - `error` (string)