Transaction Simulator
Simulate transactions on any EVM chain
Custom simulations
Run custom simulations with full control over transaction inputs, parameters, contract code, and contract states.
Simulation bundles
Test chained, interdependent transactions that involve multiple steps to preview complex executions.
Asset transfers
Get a list of the expected asset transfers to ensure your transactions execute with the desired results.
Industry-recognized simulations for successful DeFi transactions
Asset & balance changes
See the expected asset and balance changes for ERC-20 and ERC-721 tokens with corresponding dollar values.
Transaction status
Make sure your transactions execute successfully and with the intended results before sending them on-chain.
100% accurate gas estimates
Determine how much gas is needed for successful execution to prevent failures caused by out-of-gas errors.
Human-readable errors
Get a warning with a clear, human-readable message on the cause of potential transaction failure.
Transaction execution data
Analyze transaction execution, including emitted events, state changes, and involved contracts.
Shareable links
Share links to failed transaction simulations to quickly find a solution with your team.
Indispensable simulation infrastructure for transaction insights
Dapp integrations
As the underlying simulation infrastructure of many key DeFi solutions, Transaction Simulator allows dapp and wallet users to simulate Ethereum transactions, preview their expected outcomes, and send them with confidence.
Transaction previews
Integrate simulations in your wallet or dapp to give users insights into transaction results before signing. Help users make confident decisions by displaying transaction status, asset transfers, and gas usage.
Learn moreSimulation mode
Run your dapp on a simulated network to easily onboard users gas-free. Get the most recent network state and allow users to experiment with DeFi strategies without spending real money.
Learn more
Issue resolution
Replay failed Ethereum transactions to understand what went wrong during execution. Resimulate the execution with updated contract code and transaction parameters to test a bug fix before shipping it to production.
Learn moreEdit contract code
Update contract source code to apply a bug fix and see how changes affect the result of a transaction.
Override states
Test hypothetical scenarios by overriding contract storage and balances using custom values.
Impersonate accounts
Simulate sending transactions from any public account without requiring its private key.
Governance proposals
Simulate governance proposals to preview proposal effects and secure DAO voting. Manipulate the simulation environment to reflect a desired state by adjusting block numbers, timestamps, and state overrides. Inspect the execution, including state changes and emitted events, to avoid unwanted effects or hidden security risks.
Powering major DeFi solutions
Our users quite like the Simulator feature. Normally, every second or minute somebody is simulating transactions.
Richard Meissner
Co-Founder, Safe
Simulations allow us to provide a better UX/UI experience to our users without creating an environment on a testnet. Our users can easily test transactions against real Mainnet data, see swap rates, and what their yield looks like before spending any money.
Thrilok Kumar
Head of Product at Instadapp
If people interact with our products, we don't want them to lose any money anywhere. We feel a social responsibility for ensuring that people can interact safely with our products, and simulations allow us to do that.
Connor Howe
Co-Founder and CEO at Enso Finance
How to simulate transactions
curl https://mainnet.gateway.tenderly.co/$TENDERLY_NODE_ACCESS_KEY
-X POST
-H "Content-Type: application/json"
-d '{
"id": 0,
"jsonrpc": "2.0",
"method": "tenderly_simulateTransaction",
"params": [
{
"from": "0xd8da6bf26964af9d7eed9e03e53415d37aa96045",
"to": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
"gas": "0x0",
"gasPrice": "0x0",
"value": "0x0",
"data": "0xa9059cbb00000000000000000000000020a5814b73ef3537c6e099a0d45c798f4bd6e1d60000000000000000000000000000000000000000000000000000000000000001"
},
"latest"
]
}'
