When I build a Phantom wallet integration (using [these docs][1]) on a page, it doesn't include the backend in the transaction at all. 

**How does the backend hear about that transaction?** The back of house is not signing and sending the transaction, the front is. 

So the frontend would have to send signatures to.. my backend? 

How could I trust the users packet? What if it fails to deliver? What if the user spams my server with false signatures to validate?


  [1]: https://docs.phantom.app/solana/sending-a-transaction