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Access to full transaction data on all transactions & addresses
Broadcast and verify transactions with real-time monitoring
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Detailed blockchain history and transaction data for any address.
Full smart contracts metadata, including token symbols & token names
Dedicated nodes infrastructure for leading blockchains using JSON-RPC
Address validation, encoding & cryptographic tasks optimizations
Shared node infrastructure for top blockchains using JSON-RPC.
Real-time notifications for events on top blockchains. Response under 100ms.
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Sync and manage HD wallets, keys and addresses
Prepare EVM transactions, including token transfers
Access to full transaction data on all transactions & addresses
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Test EVM transactions, optimize gas fees and identify security flaws
Developing on Ethereum comes with unique challenges: transactions can fail due to contract logic, users often waste ETH on gas for unsuccessful calls, and debugging complex smart contract interactions is never straightforward. Transaction simulation solves these problems by allowing developers to test and preview Ethereum transactions without spending gas, ensuring predictable outcomes before broadcasting them on mainnet.
This guide explains how Ethereum transaction simulation works, why it is critical, and how you can integrate it into your development workflow using Crypto APIs’ Transaction Simulator.
When building decentralized applications or deploying smart contracts, every transaction can have significant cost and impact. Simulation provides developers with:
For teams managing high transaction volumes, this can mean thousands of dollars saved and a smoother, more reliable user experience.
Understanding the structure of a simulation helps developers interpret results correctly.
A request typically includes:
The response usually provides:
Crypto APIs’ Transaction Simulator extends this with multi-transaction bundle simulation, realistic mainnet previews, and detailed error reporting, giving developers full visibility into what will happen before going live.
Crypto APIs makes it straightforward to integrate simulation into your workflow through a REST API. Here’s how you can get started:
Create an account on Crypto APIs and obtain an API key. This key is required for all requests.
Define the transaction you want to test: chain (e.g., Ethereum mainnet), addresses, value, gas configuration, and encoded input data if calling a contract.
Use the REST endpoint documented in the Crypto APIs developer portal. The request doesn’t require ETH in the “from” account since no actual gas is spent.
Check whether the transaction would succeed, the gas used, emitted events, and any balance or token changes. If the simulation shows a revert, inspect the reason and adjust your contract logic or inputs.
Developers often integrate transaction simulation into:
While simulation is powerful, it isn’t a perfect crystal ball. Developers should keep these caveats in mind:
To maximize the value of transaction simulation, follow these practices:
Here’s where transaction simulation proves invaluable:
Do I need ETH in the sender account to simulate?
No. Simulation does not spend real gas or require balances.
Will results always match mainnet execution?
They are highly accurate, but not guaranteed. State changes and mempool activity can cause differences.
Where do I find the exact request and response formats?
The Crypto APIs developer documentation provides the complete schema and examples.
Which networks are supported?
Ethereum mainnet is supported, with additional EVM chains being added progressively.
Simulating Ethereum transactions before broadcasting is no longer optional — it’s essential for reducing costs, preventing failures, and improving both developer efficiency and end-user trust.
With features like bundle simulation, detailed error reporting, gas optimization, and realistic mainnet previews, the Crypto APIs Transaction Simulator is built to help developers deliver safer and more cost-efficient blockchain applications.
Whether you’re building a DeFi protocol, managing multi-sig flows, or creating a user-friendly wallet, integrating transaction simulation into your process ensures smoother execution and fewer surprises.
👉 Explore the Crypto APIs Transaction Simulator and start simulating your Ethereum transactions today - without wasting a single gwei.