Transaction simulation is one of Rabby's core security features. It provides a "preview" of your transaction, translating complex code into readable words so you can understand exactly what you are signing and avoid blind signing.
Why it Matters
When you interact with a DApp, the website interface tells you what you're doing (e.g., "Swap 1 ETH for 2500 USDT" or "Claim Rewards"). However, you shouldn't have to blindly trust the DApp. Websites can be compromised by scammers who alter the code to trick you into signing a transaction that actually drains your wallet.
Rabby exposes the truth by showing you:
Balance Changes: Exactly how many tokens will leave your wallet and how many you are expected to receive.
The Reality of the Transaction: If a site says "Claim" but the simulation shows "Transfer," you can clearly spot it before you sign.
Security Engine & Risk Alerts
Beyond showing you the balance change, Rabby's security engine scans the simulation for hidden dangers. If a risk is detected, a yellow or red exclamation mark (!) will appear. You can click these icons to view the specific details.
Rabby's security engine scans for various threats across different types of interactions. Here are some common examples:
Token Approvals: When giving a contract permission to move your tokens, Rabby scans the spender:
EOA Address: The spender is a personal account (EOA), not a smart contract—a common sign of a scam.
Trust Value $0: This contract has no on-chain reputation (calculated by how much total value is already approved to it).
Deploy Day < 3: The contract was created within the last three days.
Asset Swaps: When making a trade, Rabby checks the health of the swap:
High Price Impact: You will receive far less value than what you are paying, leading to a significant loss.
Scam Token Detected: You are about to receive a known malicious token.
Signatures & Permissions: Rabby also scans "Gasless" signatures (like Permits) that don't cost gas but can still move your funds.
How to Handle Security Warnings
If a risk is detected, the Sign button will be disabled. We recommend reviewing each warning carefully before taking action.
If you understand the potential danger and choose to proceed, click "Ignore All" to enable the Sign button. Please note that by clicking "Ignore All," you do so at your own risk; you acknowledge the warnings and assume full responsibility for the transaction. Rabby Wallet is not liable for any loss of funds resulting from ignored security risks.
What if "Simulation Failed"?
A "Simulation Failed" message means the transaction will likely fail on-chain. This is usually caused by an error within the smart contract itself. In this case, we recommend not forcing the transaction to avoid wasting gas fees. Contact the DApp or contract owner for support.
If you believe a risk warning is incorrect
If you think the detected risks are incorrect, please reach out to the official Rabby Support team. To help us investigate, please provide:
A screenshot of the signing page showing the warnings.
Either the Transaction Hash (if already signed) or the Raw Data (if not yet signed).
