Events

Move events serve the same product purpose as Solidity events: signal important on-chain state changes to off-chain readers.

Solidity event

event MessageAdded(address sender, string message, uint256 addedAt);

Move event

#[event]
struct MessageAdded has drop, store {
    sender: address,
    message: String,
    added_at: u64,
}

Emitting the event

emit MessageAdded(sender, message, block.timestamp);

event::emit(MessageAdded {
    sender,
    message,
    added_at: timestamp::now_seconds(),
});

Move events are first-class structs. That gives you a cleaner typed model, and they can be queried later through the Indexer or transaction APIs depending on the use case.