curl --request POST \
  --url https://api.extract.page/v1/files \
  --header 'Content-Type: application/json' \
  --header 'X-API-KEY: <api-key>' \
  --data '
{
  "size_bytes": 123,
  "filename": "<string>",
  "content_type": "<string>"
}
'

{
  "id": "<string>",
  "customer_id": "<string>",
  "status": "<string>",
  "size_bytes": 123,
  "created_at": "<string>",
  "expires_at": "<string>",
  "upload": {
    "method": "<string>",
    "url": "<string>",
    "expires_at": "<string>"
  },
  "object": "file",
  "filename": "<string>",
  "content_type": "<string>",
  "sha256": "<string>"
}