Glamsterdam Goes Live on Ethereum’s Sepolia Testnet

Ethereum activated its Glamsterdam network upgrade on the Sepolia testnet on Oct. 6, putting changes to block building, execution and gas accounting into a public test environment. The Ethereum Foundation’s announcement set the activation for epoch 353,024, slot 11,296,768, at 13:53:36 UTC; infrastructure provider Alchemy reported the fork went live at that time. Sepolia is the first public testnet running Glamsterdam. The activation does not set a date for Hoodi or Ethereum mainnet.

Which protocol changes are being tested on Sepolia?

Glamsterdam combines execution-layer changes grouped under Amsterdam with consensus-layer changes grouped under Gloas. Among the scheduled changes, EIP-7732 moves proposer-builder separation into the protocol, while EIP-7928 adds block-level access lists. The Foundation’s announcement lists both EIPs among the upgrade’s scheduled inclusions.

Under EIP-7732, block construction is separated from block proposal and attestation within the protocol. Alchemy describes the resulting data-propagation window as extending from about two seconds to roughly nine. That gives blocks more time to propagate data, but Sepolia’s fork is a test of the coordinated client changes, not evidence that the same performance outcome has been established on mainnet.

EIP-7928 makes a block-level access list available before the block’s transactions execute. The list records which accounts and storage slots the block touches. Clients can use that information to identify independent work and execute it in parallel, where dependencies allow. The access list supplies information for parallel execution; it does not make dependent transactions independent.

How does Glamsterdam change state gas costs?

EIP-8037 changes how gas is charged for creating permanent state, including deploying contracts and writing new storage. Alchemy says the new pricing ties cost to the amount of state created, so storage-heavy operations cost more than under the previous pricing and gas estimates based on older assumptions may undercount the required gas.

The change targets the long-term storage burden that account and contract data impose on Ethereum nodes. The Ethereum Foundation’s Glamsterdam roadmap describes a separate state-gas reservoir: state-creation charges draw from that reservoir, while the GAS opcode reports execution gas remaining. This separates accounting for computation from accounting for new permanent state. The roadmap presents this as part of the upgrade’s effort to price state growth more directly; Sepolia testing will expose how client implementations and applications handle the new rules.

What does the Sepolia fork require from operators?

Nodes must follow the upgraded rules after activation, so operators need compatible execution-layer and consensus-layer clients. The Foundation’s announcement says operators should update both layers; validators must also update their beacon node and validator client. A node that does not support the new rules cannot follow the upgraded network after the fork.

Sepolia is also testing a 200 million gas limit, according to Alchemy. That is a testnet parameter, not a reported change to mainnet’s gas limit. Some client configurations do not adopt the higher limit automatically: the Foundation’s announcement says Prysm and Teku users who want to propose at 200 million must configure it explicitly.

For developers, the practical checks include contract deployments, storage writes, sponsored transactions and cached gas estimates. Alchemy says fixed gas budgets and estimates made before EIP-8037 may need review. The Foundation advises application and tooling developers to test against Sepolia and examine effects on gas accounting, logs, opcodes and client interfaces. Hoodi and mainnet activation dates remain undecided, according to the Foundation.

References

• Ethereum Foundation’s announcement — blog.ethereum.org
• Alchemy reported the fork went live at that time — alchemy.com