Token Balance Storage Slot Searcher

Finding the storage slot of an ERC20 token can be useful for updating the balance of a token on a forked network.

It supports the majority of ERC20 tokens accross Vyper and Solidity. Even proxies and cases for which storage contract where balances are stored is different than the token itself (eg. SNX). Note that for some contracts balance is not solely determined by the storage slot, so in those cases setting the storage slot to a specific value may not be exectly reflected in the balance - it could be slightly higher or lower.

The API is live on: http://token-bss.xyz.

• ethereum / eth
• arbitrum / arb
• optimism / opt
• avalanche / avax

Request:

$ curl http://token-bss.xyz/opt/0x513c7e3a9c69ca3e22550ef58ac1c0088e918fff | jq

Response:

{
  "success": true,
  "msg": {
    "token": "0x513c7e3a9c69ca3e22550ef58ac1c0088e918fff",
    "contract": "0x513c7e3a9c69ca3e22550ef58ac1c0088e918fff",
    "slot": "0x34",
    "updateRatio": 1.0011,
    "lang": "solidity"
  }
}

Checkout Server README for more information on usage.

• Storage Slot Discovery: Trace ERC20 balanceOf calls to determine the storage slot of a token and where is it stored.
• Balance Updating: Directly update the balance of an ERC20 token on a forked network.

Checkout CLI README for more information on usage.

match token_bss::find_slot(&provider, token, None, None).await {
    Ok((contract, slot, update_ratio, lang)) => {
        println!("{symbol}({token:?}): {contract:?}({lang}) - {slot:?} / ΔR: {update_ratio}")
    }
    Err(e) => println!("{symbol}({token:?}): {e}"),
}

$ cargo run --example eth_token_support

Contributions are more than welcomed!

Reach out on X