@Dennison created a Gas Station Network sample chat app
The app works on mobile and desktop.
The code is available on GitHub:
Aside from the awesomeness of the Gas Station Network, the smart contract for the chat app is also stateless.
event message(string message, address user, uint timestamp, bytes32 uuid);
function postMessage(string memory _msg) public {
emit message(_msg, getSender(), now, keccak256(abi.encodePacked(_msg, now, getSender())));
}
Leeroy (social network on Ethereum) used stateless smart contracts, and the technique was adopted by Peepeth.
James the creator of Leeroy explains stateless smart contracts: