Transaction simulation

Instead of displaying raw data or a contract function name, the wallet or a security extension executes the transaction on a copy of the blockchain state and reports the outcome in plain terms: which tokens leave the wallet, which arrive, and which approvals are granted. Many tools also check the destination against lists of known drainer contracts and phishing domains and warn before the user confirms.

Simulation has become one of the most practical defences against wallet drainers and ice phishing, because a malicious claim page that promises a reward will show up as the user's assets moving out. It is now built into several popular wallets and offered by dedicated extensions and APIs, and smart account wallets use it to preview batched calls.

Results are a forecast, not a guarantee. The state can change between simulation and inclusion, contracts can behave differently depending on block data, and some scams detect simulators and behave innocently during the preview. Off-chain signatures such as permits do not move tokens immediately, so a clean simulation can hide a dangerous approval if the tool does not decode it.