Ethereum is moving forward with its ambitious Layer 1 scaling roadmap, officially announcing that the highly anticipated Glamsterdam network upgrade is scheduled to activate on the Sepolia testnet. The upgrade will take place at epoch 353,024 and slot 11,296,768, which translates to October 6, 2026, at 13:53:36 UTC. Following in the footsteps of the Fusaka upgrade, Glamsterdam represents a major technical milestone for the network, introducing critical protocol changes designed to optimize block production, validation efficiency, and resource accounting across the ecosystem.
The Glamsterdam upgrade is a comprehensive overhaul that combines the Amsterdam execution layer upgrade with the Gloas consensus layer upgrade. Together, these two components introduce headlining changes aimed at fundamentally transforming how Ethereum blocks are produced, validated, and priced. Among the most significant advancements are enshrined proposer-builder separation and block-level access lists, both of which are designed to support significantly higher Layer 1 throughput without compromising the decentralization or security of the network.
Glamsterdam Overview
At the core of the Glamsterdam upgrade are architectural changes that address some of the long-standing challenges associated with Ethereum’s execution capacity and state growth. By embedding proposer-builder separation directly into the protocol and introducing structured access lists, the core development teams are laying a robust foundation for future scaling efforts. These changes are expected to streamline how validators interact with external block builders while simultaneously making state reads and transaction validation much more efficient for node operators.
In addition to structural improvements to block building, Glamsterdam brings sweeping adjustments to gas accounting. These modifications are specifically tailored to better reflect the true resource usage and execution costs associated with state growth. As Ethereum continues to handle heavy transaction volumes, ensuring that gas pricing accurately mirrors the cost of network resources remains a top priority for core developers and researchers alike.
Enshrined Proposer-Builder Separation
One of the most anticipated components of the Glamsterdam upgrade is the formal introduction of enshrined proposer-builder separation, commonly referred to as ePBS, via EIP-7732. Historically, Ethereum relied on out-of-protocol middleware to facilitate the complex exchange between block proposers and specialized block builders. EIP-7732 brings this separation directly into Ethereum’s consensus protocol, creating a standardized framework where a proposer includes a builder’s commitment to an execution payload, and the builder subsequently reveals that payload.
Under this new system, the protocol automatically handles payments to the proposer, significantly reducing reliance on trusted third-party middleware. Furthermore, ePBS achieves a vital architectural separation between consensus validation and execution validation. This separation grants validators considerably more time to thoroughly validate execution payloads before they are finalized. To ensure reliability, a dedicated payload timeliness committee will attest to whether the builder successfully revealed its payload and whether the corresponding blob data was made available on time. Validator operators and engineering teams maintaining builder infrastructure are strongly advised to review these new protocol duties and operational interfaces ahead of the activation.
Block-Level Access Lists
Complementing ePBS is the introduction of block-level access lists, or BALs, governed by EIP-7928. This mechanism enforces the recording of all accounts and storage locations accessed over the course of a block, alongside post-transaction state changes. By providing a clear and comprehensive record of state access upfront, these lists empower client software to read state data from disk in parallel, validate transactions simultaneously, and compute state roots with a much higher degree of computational efficiency.
The combination of ePBS and block-level access lists creates a powerful synergy. Together, they provide the necessary infrastructure to scale Ethereum’s execution capacity while keeping the hardware and operational requirements for node operators practical, thereby safeguarding the network’s decentralized nature.
Gas Pricing and State Growth
Glamsterdam also introduces critical updates to gas accounting through EIP-8037 and EIP-8038. EIP-8037 specifically increases and separately meters the cost associated with creating new state, while EIP-8038 updates the general costs related to state access. Additional adjustments cover intrinsic transaction gas, calldata handling, access lists, and broader block gas accounting rules.
These changes mean that application developers will need to carefully test their smart contracts and gas estimation logic against the new rules before the mainnet rollout. Contracts that rely on fixed gas stipends, hardcoded gas limits, or assumptions regarding remaining gas may require modifications to function correctly. Developers are encouraged to consult the Glamsterdam repricing impact guide and utilize available testing resources to identify any vulnerable contracts within their codebases.
Additional Developer and Validator Improvements
Beyond its headline features, Glamsterdam packs a variety of developer-friendly enhancements and protocol-level improvements. The upgrade includes the introduction of ETH transfer logs, a dedicated slot-number opcode, an increased maximum contract size limit, a deterministic factory contract, and new stack-manipulation instructions. On the consensus side, improvements feature forward-compatible data structures, provisions to exclude slashed validators from the proposal queue, and increased exit and consolidation churn rates to improve validator set management.
Security and the Ethereum Bug Bounty Program
To ensure a smooth and secure deployment, the Ethereum Bug Bounty Program has been officially expanded to cover the Glamsterdam specifications and associated EIPs. Client implementations become eligible for bug bounty rewards as soon as their respective releases are published and officially listed. Security researchers and auditors are encouraged to review the specifications and report any vulnerabilities in accordance with the established guidelines of the Ethereum Bug Bounty Program.
Deployment Schedule and Client Releases
The agreed deployment schedule places the Sepolia testnet activation at epoch 353,024 and slot 11,296,768, occurring on October 6, 2026, at 13:53:36 UTC, with a corresponding UNIX timestamp of 1791294816. Activation dates for the Hoodi testnet and Ethereum mainnet have not yet been finalized and will be announced by client teams at a later date.
Node operators running Sepolia nodes must update both their execution layer and consensus layer clients prior to the activation timestamp. For stakers, it is critical to ensure that both the consensus layer beacon node and the underlying validator client are updated to compatible versions. Client teams have begun releasing compatible software versions, and operators should closely monitor release notes to confirm support for the Sepolia fork. For instance, specific client configurations—such as those required by Prysm and Teku regarding default versus customized gas limits for proposers—must be reviewed carefully by validators to ensure uninterrupted operations and proper alignment with the new protocol rules.
As the Ethereum ecosystem counts down to the Sepolia activation, application developers, infrastructure providers, and node operators should utilize the available testnet environment to verify their setups, test updated smart contracts, and ensure complete readiness for the broader rollout of the Glamsterdam upgrade.
Comments (0)