What is Ethereum's Glamsterdam upgrade?

What is Glamsterdam, and how far along is it?

Ethereum changes its rules through coordinated upgrades called hard forks. Each one bundles a set of Ethereum Improvement Proposals (EIPs) that every node must adopt at the same moment. Glamsterdam is the name of the next bundle. The Ethereum Foundation's October 16, 2026 announcement lists more than twenty EIPs across execution, consensus and networking changes.^[1] If you are new to how the network is organised, start with what is Ethereum.

Upgrades are rehearsed on test networks before they touch real money. Glamsterdam activated on the Sepolia testnet on October 6, 2026, and the Hoodi testnet is scheduled to follow on October 26, 2026.^[1] The same announcement states plainly that the mainnet activation date has not been decided and will be announced once client teams agree on it.^[1]

What does enshrined proposer-builder separation change?

In each slot, one validator is chosen to propose the next block. In practice, most proposers do not assemble the list of transactions themselves. Specialised builders do, and the hand-off between the two has run through trusted middleware that sits outside the protocol.^[1]

EIP-7732, called enshrined proposer-builder separation or ePBS, brings that hand-off inside Ethereum's own rules. It introduces builders as a new in-protocol role.^[2] The proposer picks a builder's signed bid, which commits to a specific execution payload and a payment to the proposer; the full payload is revealed afterwards.^[2]

A subset of validators forms a Payload Timeliness Committee. Its members vote on whether the builder revealed the committed payload, and its blob data, on time.^[2] They do not have to execute the payload themselves, which moves the heavy checking out of the most time-sensitive part of the slot.^[2]

What are block-level access lists?

A node cannot safely run transactions side by side unless it knows in advance which accounts and storage slots each one will touch. An earlier proposal, EIP-2930, let transactions declare this, but the lists were optional and not enforced.^[3]

EIP-7928 makes the declaration mandatory at block level. A block-level access list records every account and storage location accessed while the block executed, together with the values after execution.^[3] With that map in hand, the proposal says clients can read from disk in parallel, validate transactions in parallel, compute the new state root in parallel and even update state without re-executing transactions.^[3]

How does Glamsterdam change gas costs?

Gas is the unit Ethereum uses to price computation and storage. Glamsterdam includes a group of repricing EIPs.^[1] According to the announcement:

• Creating new state (new accounts or storage) costs more and is metered separately (EIP-8037).^[1]
• Charges for reading and writing existing state are updated (EIP-8038).^[1]
• The base cost of a transaction becomes resource-based (EIP-2780), and the calldata floor and access-list costs rise (EIP-7976, EIP-7981).^[1]
• Block gas accounting stops using refunds (EIP-7778).^[1]

On both test networks the block gas limit rises to 200 million at activation.^[1] None of this tells you what fees will cost after a mainnet launch: a fee still depends on the gas a transaction uses and the price per unit at that moment. Contracts that assume fixed gas costs are the most likely to need changes, which is why the announcement points developers to a repricing guide.^[1]

What do node operators, stakers and holders need to do?

The answer depends on who you are. The announcement gives separate instructions for each group:^[1]

1. Node operators on Hoodi must update both their execution client and consensus client to releases that support Glamsterdam before the activation time.^[1] Read what a node is if the two-client set-up is new to you.

2. Stakers on Hoodi must update the beacon node and the validator client, and review the new ePBS duties and their gas limit settings.^[1] Our guide to staking explains the validator role.

3. Developers should test on Sepolia and Hoodi and check whether gas accounting, logs or opcodes affect their contracts and tools.^[1]

4. Mainnet users and ETH holders need to take no action for the Hoodi activation.^[1]

What mistakes do people make about Ethereum upgrades?

• Treating a testnet date as the mainnet date. Sepolia and Hoodi dates are rehearsals; the mainnet time has not been chosen.^[1]
• Believing they must move or "upgrade" their ETH. Ordinary holders were told no action is needed.^[1] A message asking you to send coins, connect a wallet or enter a seed phrase "for the upgrade" is a scam pattern; see phishing in crypto.
• Assuming every upgrade lowers fees. Glamsterdam raises some costs, such as creating new state.^[1]
• Reading a proposal as final. On October 17, 2026 both headline EIPs were in Last Call status with a November 1, 2026 deadline, so details can still be edited.^[2][3]
• Confusing layers. Glamsterdam changes Ethereum's base layer; rollups have their own upgrade schedules. See Ethereum rollups explained.