# Transaction Simulator

## Simulate transactions and know in advance how they will behave onchain

The Crypto APIs Transaction Simulator is live in the Blockchain API: send an Ethereum transaction to the simulator before you broadcast it, on mainnet or Sepolia, and see whether it succeeds or reverts, the gas it uses and the fee, without paying a network fee. Minimize losses, optimize gas consumption, test various transaction scenarios, perform bundle transaction testing, take strategic actions, and improve transaction security.

## Blockchain Transaction Simulator

Every enterprise client has unique use cases, requirements, and levels of service customization. No matter what you need you're in the right place. Explore our solutions below or share your specific requirements with us.

### Reduce Network Fees

Optimize gas fees by adjusting transaction parameters. Calculate transaction fees accurately, manage gas consumption expectations, and eliminate unnecessary gas expenses.

### Prevent Gas Failure

Running out of gas or high gas fees can result in costly failures. Identify and prevent these issues before they occur with our Blockchain Transaction Simulator.

### Detect Еrrors & Improve Security

Detect and prevent transaction failures and reverts even in the preparation stage of transactions. Identify potential risks in transactions, smart contracts, and other blockchain activities associated with overall stability and security.

### Realistic Mainnet Simulation

Experience authentic mainnet results without the risk or expense of actual on-chain transactions. Gain precise insights into transaction behavior with our risk-free simulation.

### Improve User Experience

Provide deeper and meaningful insights to your dApp users regarding their interactions with your system. Create a simplified feedback to enhance users experience and engagement.

### Efficient DApp Testing & Optimization

Simulate transactions to assess confirmation times, fees, and errors. Ensure DApps and smart contracts functionalities are intact, and accelerate development by fixing identified bugs before deployment. Verify inputs, outputs, and transaction structure to guarantee optimal performance.

### Request additional blockchains

The simulator is live for Ethereum, on mainnet and Sepolia. Need it on another blockchain? Tell us which one on the page.

## What we support

### Mainnet and Sepolia

Ethereum mainnet and the Sepolia test network. Other blockchains on request.

## Related

- [/products/blockchain-api/prepare-transactions](/products/blockchain-api/prepare-transactions) — build the transaction to simulate.
- [/products/blockchain-api/blockchain-fees](/products/blockchain-api/blockchain-fees) — fee and gas estimates.
- [Prepare Transactions API reference](https://developers.cryptoapis.io/v-2.2024-12-12-175/RESTapis/prepare-transactions) — the endpoint reference in the developer docs.
- [Developer portal](https://developers.cryptoapis.io/) — full REST API reference.