FAQs

What chains do you support?

ChainNetwork
EthereumMainnet
EthereumGoerli
PolygonMainnet
PolygonMumbai
ArbitrumMainnet
ArbitrumGoerli
OptimismMainnetQ1 2023
OptimismGoerliQ1 2023

Wrapped tokens

NetworkNameContract Address
Eth MainnetWETH0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2
Eth GoerliWETH0xb4fbf271143f4fbf7b91a5ded31805e42b2208d6
Polygon MainnetWMATIC0x0d500b1d8e8ef31e21c99d1db9a6444d3adf1270
Polygon MumbaiWMATIC0x9c3c9283d3e44854697cd22d3faa240cfb032889
Arbitrum MainnetWETH0x82af49447d8a07e3bd95bd0d56f35241523fbab1
Arbitrum GoerliWETH0x1dfc378641f06f4095e9434017bf335018550c55

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 - see here.

NetworkNameContract Address
Eth MainnetCryptoKitties0x06012c8cf97bead5deae237070f9587f8e7a266d
Eth MainnetCryptoPunks0xb47e3cd837ddf8e4c57f05d70ab865de6e193bbb

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

You can access the top level gasUsed field.

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.

Pricing

The Simulation APIs cost 2500 CU per call - see Compute Unit Costs.