curl --request GET \
  --url https://api.apexxcloud.com/api/v1/files/signed-url \
  --header 'X-Access-Key: <api-key>' \
  --header 'X-Signature: <api-key>' \
  --header 'X-Timestamp: <api-key>'

{
  "data": {
    "url": "https://cdn.apexxcloud.com/f/abc123/example.jpg?signature=xyz789",
    "expires_in": 3600,
    "is_public": false
  }
}