Why it matters:

Validators and builders can see state touch patterns *before* parallel execution work gets serious.

Glamsterdam pairs this with ePBS on the consensus layer.
EthereumJS covers the execution side — run it locally.

Builder flow in @ethereumjs/vm:

runBlock(vm, {
block,
generate: true,
})

No extra flag beyond Amsterdam.
The VM accumulates accesses automatically while executing.

Then read:

result.blockLevelAccessList

One plain ETH transfer → 4 accounts in the BAL on our example.

Header hash must match bal.hash().
Mismatch = invalid block.

Validator flow:

runBlock(vm, {
block,
blockAccessList: balJson,
})

Pass the known list (JSON, RLP, or BlockLevelAccessList).
VM checks structure + hash, then compares against execution.

Run it (Node 20+, any OS):

mkdir amsterdam-bal && cd amsterdam-bal
npm init -y
npm i @ethereumjs/vm@10.1.3 @ethereumjs/block@10.1.3 @ethereumjs/common@10.1.3 @ethereumjs/tx@10.1.3 @ethereumjs/util@10.1.3 tsx

Copy runBlockBALGenerate.ts, then:

npx tsx runBlockBALGenerate.ts

github.com/ethereumjs/eth…

The gotcha:

BAL is not per-tx — it is per *block*.
Use Hardfork.Amsterdam (full bundle), not EIP-7928 in isolation.

Peers exchange it separately (eth/71).
Your indexer cannot ignore the header hash.

Full walkthrough + validator example:
runBlockBALValidate.ts

Docs:
github.com/ethereumjs/eth…

Experimental — not production.
Next: ETH transfer logs (EIP-7708). 🚀

[ END OF THREAD ]