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TLDR:
  • On the Blast L2 network, ETH or stablecoins automatically rebase unless configured otherwise through one of their precompiled contracts.
  • Each account can set its yield mode (AUTOMATIC, VOID, or CLAIMABLE). AUTOMATIC is default, so VOID or CLAIMABLE indicates nonstandard behavior.
  • In this Python example, we filter recent blocks for addresses, then query each address’s yield mode on both USDB and WETH contracts, flagging any VOID or CLAIMABLE.
  • This helps identify accounts intentionally opting out of the default auto-yield or wishing to claim accrued yield separately.

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Main article

Blast is an EVM-compatible L2 protocol with a major modification—ETH and stablecoins bridged over to the Blast network yield natively. As an example of what this means—if you have your ETH on your address on the Blast network and do nothing, your ETH balance will grow (rebase positively, to be more technical) over time. Check out the Blast documentation to understand where the yield is coming from. For the purposes of this tutorial, we focus purely on the technical part. There are a few precompiled contracts on Blast that make the network tick. For the full list, see Blastdocs: Contracts. The ones that provide native yield generation are: Inspecting these contracts will reveal that each of them has the same yieldMode setting: 
enum YieldMode {
    AUTOMATIC,
    VOID,
    CLAIMABLE
}
You can write this setting with the configure(YieldMode yieldMode function: 
function configure(YieldMode yieldMode) external returns (uint256) {
        _configure(msg.sender, yieldMode);
This means that every USDB or WETH token on the Blast network has a yield mode assigned to it: AUTOMATIC — default mode; your USDB or WETH token rebases positively. VOID — your USDB or WETH token does not rebase or accrue claimable yield. CLAIMABLE — your USDB or WETH token does not rebase but accrues claimable yield separately. ETH or stablecoins bridged to the Blast network get assigned the default AUTOMATIC yield mode. Users can manually set any other (VOID or CLAIMABLE) mode to their assets by calling the configure(YieldMode yieldMode on each of the contracts. This is all we need to know. This seems like checking the live addresses as they interact on the Blast network for the yield mode setting might raise a flag if it’s non-default and could be useful. And this is what we are going to do in this simple tutorial. We will do a Python script that:
  • Identifies active address by extracting the from each new incoming block as from.
  • Checks each of the extracted active addresses against the USDB & WETH contracts for their yield setting and prints the result.
All of the code is in the GitHub repository.

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Prerequisites

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Step-by-step

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Get a Blast node

Log in to your Chainstack account and get a node endpoint.

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Create the script

Since the both the USDB and the WETH contracts are almost the same, we are going to use the same common ABI for both of them. Let’s first do a script that identifies and prints all active accounts in each new block that have one of the three settings: AUTOMATIC, VOID, CLAIMABLE. We’ll do this to make sure the script works as expected. 
import time
from web3 import Web3

# Connect to Blast node
w3 = Web3(Web3.HTTPProvider('CHAINSTACK_NODE'))

# Contract addresses and the common ABI
USDB_ADDRESS = '0x4300000000000000000000000000000000000003'
WETH_ADDRESS = '0x4300000000000000000000000000000000000004'
COMMON_ABI = [{"inputs":[{"internalType":"address","name":"account","type":"address"}],"name":"getConfiguration","outputs":[{"internalType":"enum YieldMode","name":"","type":"uint8"}],"stateMutability":"view","type":"function"}]

# Create contract objects
usdb_contract = w3.eth.contract(address=USDB_ADDRESS, abi=COMMON_ABI)
weth_contract = w3.eth.contract(address=WETH_ADDRESS, abi=COMMON_ABI)

# Extract "from" addresses from each new block
def handle_block(block_number, rps=25):
    block = w3.eth.get_block(block_number, full_transactions=True)
    active_accounts = set(tx['from'] for tx in block.transactions if 'from' in tx)
    delay = 1 / rps

# Check yield mode for each active account
    for account in active_accounts:
        check_yield_mode(account, usdb_contract, "USDB")
        check_yield_mode(account, weth_contract, "WETH")
        time.sleep(delay)

# Call the getConfiguration function to check the yield mode. 0 = AUTOMATIC, 1 = VOID, 2 = CLAIMABLE
def check_yield_mode(account, contract, contract_name):
    yield_mode = contract.functions.getConfiguration(account).call()
    if yield_mode == 0:
        print(f"{account} yieldMode on {contract_name} is AUTOMATIC")
    elif yield_mode == 1:
        print(f"{account} yieldMode on {contract_name} is VOID")
    elif yield_mode == 2:
        print(f"{account} yieldMode on {contract_name} is CLAIMABLE")

def main(rps=25):
    block_filter = w3.eth.filter('latest')
    while True:
        for block_number in block_filter.get_new_entries():
            handle_block(block_number, rps)

if __name__ == "__main__":
    main()
where
  • CHAINSTACK_NODE — your Blast node deployed with Chainstack
  • rps=25 — an RPS setting to make sure you stay within the limits.
Running the script will reveal that an overwhelming majority of accounts interact with on the network with the default automatic yield setting. Let’s modify the script to only print the VOID and CLAIMABLE accounts, which would be a decent enough flag for non-ordinary accounts. 
import time
from web3 import Web3

# Connect to Blast node
w3 = Web3(Web3.HTTPProvider('CHAINSTACK_NODE'))

# Contract addresses and the common ABI
USDB_ADDRESS = '0x4300000000000000000000000000000000000003'
WETH_ADDRESS = '0x4300000000000000000000000000000000000004'
COMMON_ABI = [{"inputs":[{"internalType":"address","name":"account","type":"address"}],"name":"getConfiguration","outputs":[{"internalType":"enum YieldMode","name":"","type":"uint8"}],"stateMutability":"view","type":"function"}]

# Create contract objects
usdb_contract = w3.eth.contract(address=USDB_ADDRESS, abi=COMMON_ABI)
weth_contract = w3.eth.contract(address=WETH_ADDRESS, abi=COMMON_ABI)

# Extract "from" addresses from each new block
def handle_block(block_number, rps=25):
    block = w3.eth.get_block(block_number, full_transactions=True)
    active_accounts = set(tx['from'] for tx in block.transactions if 'from' in tx)
    delay = 1 / rps

# Check yield mode for each active account
    for account in active_accounts:
        check_yield_mode(account, usdb_contract, "USDB")
        check_yield_mode(account, weth_contract, "WETH")
        time.sleep(delay)

# Call the getConfiguration function to check the yield mode. 0 = AUTOMATIC, 1 = VOID, 2 = CLAIMABLE
def check_yield_mode(account, contract, contract_name):
    yield_mode = contract.functions.getConfiguration(account).call()
    if yield_mode == 1:
        print(f"{account} yieldMode on {contract_name} is VOID")
    elif yield_mode == 2:
        print(f"{account} yieldMode on {contract_name} is CLAIMABLE")

def main(rps=25):
    block_filter = w3.eth.filter('latest')
    while True:
        for block_number in block_filter.get_new_entries():
            handle_block(block_number, rps)

if __name__ == "__main__":
    main()

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Conclusion

This tutorial guided you through creating a simple Python project that tracks and flags accounts as they come live that have a very uncommon yield mode setting.

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About the author

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Ake

Director of Developer Experience @ Chainstack Talk to me all things Web320 years in technology | 8+ years in Web3 full time years experienceTrusted advisor helping developers navigate the complexities of blockchain infrastructure