Find answers to frequently asked questions related to Alchemy's Transaction Simulation APIs
What chains do you support?
Chain | Network | |
---|---|---|
Ethereum | Mainnet | ✅ |
Ethereum | Goerli | ✅ |
Ethereum | Sepolia | ✅ |
Polygon | Mainnet | ✅ |
Polygon | Mumbai | ✅ |
Arbitrum | Mainnet | ✅ |
Arbitrum | Goerli | ✅ |
Optimism | Mainnet | ✅ |
Optimism | Goerli | ✅ |
Wrapped tokens
Network | Name | Contract Address |
---|---|---|
Eth Mainnet | WETH | 0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2 |
Eth Goerli | WETH | 0xb4fbf271143f4fbf7b91a5ded31805e42b2208d6 |
Polygon Mainnet | WMATIC | 0x0d500b1d8e8ef31e21c99d1db9a6444d3adf1270 |
Polygon Mumbai | WMATIC | 0x9c3c9283d3e44854697cd22d3faa240cfb032889 |
Arbitrum Mainnet | WETH | 0x82af49447d8a07e3bd95bd0d56f35241523fbab1 |
Arbitrum Goerli | WETH | 0x1dfc378641f06f4095e9434017bf335018550c55 |
Do you support NFTs that predate ERC721?
Yes.
We recently added support for the following NFTs that predate the ERC721 standard:
- CryptoKitties
- Cryptopunks
assetType
will be set to SPECIAL_NFT
for these collections.
This is consistent with our Transfers API.
Network | Name | Contract Address |
---|---|---|
Eth Mainnet | CryptoKitties | 0x06012c8cf97bead5deae237070f9587f8e7a266d |
Eth Mainnet | CryptoPunks | 0xb47e3cd837ddf8e4c57f05d70ab865de6e193bbb |
How can I get metadata for NFTs (ERC721, ERC155)?
You can use the collection address (contractAddress
) and token id (tokenId
) returned in the response to call our getNFTMetadata endpoint - see here.
How can I determine if a simulation was successful?
You can check if the top level error
field is null.
How can I get gas used?
alchemy_simulateAssetChanges
alchemy_simulateAssetChanges
You can access the top level gasUsed
field.
alchemy_simulateExecution
alchemy_simulateExecution
The API can return a flat or a nested response depending on the 3rd parameter passed in the request (defaults to flat response).
Flat response - gasUsed
in first call.
Nested response - gasUsed
in root call of nested response.
Simulation Limits and Pricing
- Free tier users have access to up to 1,000 simulations per day.
- Growth tier users have access to up to 50,000 simulations per day.
- Scale tier users have access to up to 75,000 simulations per day.
- Enterprise tier users can perform unlimited simulations.
Please note that bundle simulation is only available on the Growth and Enterprise tiers.