Ask HN: Your browser-to-server (XMLHttpRequest/WebSocket) free wishlist?

Adding value for the browser environment / JavaScript programmer without a dedicated server or framework or for just plain convenience.

Like health check a remote non cors-enabled endpoint. A simple HEAD request to a remote url for client side load balancing or for creating a quick page that monitors remote endpoints health. Or how about the ability to send an email - maybe enough restrictions (no attachments, limited size, throttled) could be put in place to prevent potential abuse.

I am very good at creating/scaling/maintaining the server side. So what services would be useful?