Balance deltas for a call — when this network can simulate them.
Reads public data
Network
the wallet that would sign
the contract being called
Value and calldata
wei sent with the call — 0 for a token call
paste from your wallet, or build it in the ABI encoder
Nothing is sent until you press Simulate. A result is not clearance to sign.
About transaction simulator
Simulation runs a call against the current state of the chain without broadcasting it, then reports balance deltas when the node supports eth_simulateV1. That is the question a wallet confirmation screen rarely answers. Networks without that method say so plainly — silence is not a pass. A call that moves nothing is still not clearance: an approval changes no balances when you sign it and grants permission to move everything afterwards.
Common questions
Can I preview a transaction before signing it?
Paste From, To and calldata. When the network supports it, this reports balance deltas. It signs nothing and sends nothing. On networks whose public node cannot trace balances, it says “Simulation unavailable on this network” rather than showing an empty list — an unchecked call and a quiet one look identical otherwise.
Does a simulation showing no balance change mean it is safe?
No. An approval moves nothing at the moment you sign it and grants permission to move everything afterwards, so it simulates as completely inert. Decode the calldata before trusting a transaction that appears to do nothing.