Transaction Preview — Real-Time Insights For Ethereum Mainnet

Blocknative Transaction Simulations can be used to preview the outcome of potential transactions based on the current state of the blockchain. 

The introduction of Blocknative Transaction Preview expands our Ethereum Simulation capabilities beyond inflight, signed transactions to now include on-demand insights into unsigned transactions prior to broadcasting them for inclusion on-chain. 

This new capability enables wallets, protocols, and traders to see the expected slippage, net-balance changes, and smart contract calls before authorizing transactions. 

Read on to learn more about how Transaction Preview works and its use cases for wallet and dApp developers and traders. Or explore our detailed API documents and go hands-on.

Transaction Preview Enhances Simulation Platform

The Blocknative Simulation computes and summarizes the likely results of every eligible pending transaction against the current state of the chain – in real-time, at scale, and with low latency. However, this process has historically only simulated pending transactions already in the mempool. Now, with our new Transaction Preview API, users can simulate custom, unsigned transactions against the current block height before committing anything to the blockchain.

Preview Unsigned Ethereum Blockchain Transactions

When a user submits an unsigned transaction through the Transaction Preview API, the platform will simulate it against the current block height to detail the expected results of the transaction - blazingly fast.

Blocknative's API will return detailed payloads showing decoded contract calls, net balance changes, and performance metrics. 

Users can then modify simulation inputs such including from address, gas limit, gas prices per transaction type, and transaction input to understand how these factors impact their expected balance changes.

Transaction Preview for Wallet and dApp Developers

The Transaction Preview API makes it possible for web3 wallets and dApps to show end-users:

• Accurate Ethereum transaction previews
• ETH gas consumption
• Slippage for a swap
• Updated balances
• All internal calls
• Whether internal calls will execute correctly or fail
• And whether this transaction itself will execute correctly or fail

We expect this composable API will enable new experiences for end-users — such as previewing and timing NFT Mints and seeing whether it goes through or fails without having to pay gas.

Transaction Preview API also helps developers pre-flight complex transactions, as well as simulate any transaction and see its detailed internal calls for debugging purposes.

Transaction Preview for Traders

The Transaction Preview API makes it possible for traders to: 

• Simulate different variations of a potential trade using different inputs, and execute the most profitable combination of inputs 
• Accurately assess effects of a potential trade on any pools impacted, the amount received, slippage experienced, and gas used
• Understand how variables — like gas, gas limit, and block height — impact their trades
• Understand how their previews perform with end-to-end performance metrics

And Blocknative’s Transaction Preview is fast — typically simulating transactions 10x faster than other solutions. We expect that this API will help to enable new profit opportunities for traders.

How to Leverage Transaction Preview Today

You can now go hands-on with Transaction Preview API to: 

• Show end-users accurate slippage, net balance changes, and contract calls — to ensure confidence when transacting on-chain.
• Enable better trade execution by varying inputs like gas limit, gas price, and transaction input to see how it changes the outputs. 
• Get insights from the mempool to optimize development. 
• And more.

You can begin prototyping today by creating a free account and reviewing the docs. Once you are ready to push to production, simply sign up for a commercial plan. You can also execute your findings with our Ethereum transaction API.

As always, please join our Discord Community if you have questions, concerns, or recommendations. Want to learn more? Check out our guide Understanding Ethereum Transaction Simulation.