The Ethereum network is on the cusp of a significant evolution with the upcoming "Glamsterdam" network upgrade. This pivotal event, following the Fusaka upgrade, is designed to propel Ethereum’s Layer 1 scaling roadmap forward by introducing crucial enhancements such as enshrined proposer-builder separation (ePBS), block-level access lists (BALs), and refined gas pricing mechanisms. These changes aim to optimize transaction processing, improve network throughput, and better align gas costs with the actual computational and state growth demands on the blockchain.
The Glamsterdam network upgrade is slated to activate on the Sepolia testnet on October 6, 2026, at epoch 353,024, corresponding to slot 11,296,768, precisely at 13:53:36 UTC. This activation on Sepolia serves as a critical final testing phase before potential mainnet deployment. While the Sepolia activation date is firmly established, the deployment schedules for the Hoodi testnet and the mainnet are yet to be determined, pending further community consensus and client team readiness.
Node operators are urged to ensure their execution and consensus layer clients are updated to the latest Sepolia-compatible versions prior to the activation. These updated client versions will be progressively integrated into official release tables as they are confirmed, providing a clear roadmap for network participants.
Glamsterdam: A Synergistic Upgrade for Enhanced Performance
The Glamsterdam upgrade represents a harmonious integration of the Amsterdam execution layer upgrade and the Gloas consensus layer upgrade. Its most impactful features are enshrined proposer-builder separation (ePBS) and block-level access lists (BALs). These innovations fundamentally alter how blocks are produced and validated, laying the groundwork for substantially increased L1 throughput.
Enshrined Proposer-Builder Separation (ePBS)
At the heart of Glamsterdam’s scaling ambitions lies enshrined proposer-builder separation (ePBS), as detailed in EIP-7732. This EIP formalizes the separation between block proposers and block builders directly within Ethereum’s consensus protocol. Under ePBS, a proposer includes a builder’s commitment to an execution payload within the consensus block. Subsequently, the builder reveals this payload, along with the associated data. A key benefit of this enshrined approach is that the protocol itself manages the payment to the proposer, mitigating the reliance on potentially less secure, trusted middleware for the crucial exchange between proposers and builders.
This architectural shift also ushers in a more robust separation between consensus validation and execution validation. This decoupling grants validators more time to meticulously validate execution payloads. A specialized "payload timeliness committee" will be responsible for attesting to whether the builder has revealed its payload and if the corresponding blob data was made available within the stipulated timeframe. Consequently, validator operators and teams responsible for maintaining builder infrastructure must thoroughly review the newly defined duties and interfaces to ensure seamless integration and operation.
Block-Level Access Lists (BALs)
Complementing ePBS, Block-Level Access Lists (BALs), introduced via EIP-7928, represent another significant leap forward. BALs enforce the recording of all accounts and storage locations accessed during the processing of a block, alongside the post-transaction state changes. This detailed record provides immense benefits for network efficiency. By having this explicit list of accessed state, clients can more effectively read state from disk in parallel, validate transactions concurrently, and compute state roots with greater efficiency. The combined impact of ePBS and BALs is a robust foundation for scaling Ethereum’s execution capacity while ensuring that block validation remains practical and manageable for node operators.
Rethinking Gas Pricing and State Growth
Glamsterdam also addresses the critical issue of gas pricing, recalibrating it to more accurately reflect the actual resource consumption on the network. EIP-8037 introduces an increase and separate metering for the cost of creating new state, a crucial step in accounting for the ever-growing Ethereum state. Concurrently, EIP-8038 updates the costs associated with accessing existing state. These foundational changes are further bolstered by adjustments to intrinsic transaction gas, calldata costs, access list processing, and overall block gas accounting.
This repricing initiative necessitates careful consideration from application developers. They are strongly advised to rigorously test their smart contracts and gas estimation mechanisms against these new rules. Contracts that rely on fixed gas stipends, hardcoded gas limits, or assumptions about the remaining gas available may require significant modifications. A comprehensive "Glamsterdam repricing impact guide" has been published, offering guidance on identifying affected contracts and providing testing methodologies to ensure smooth transitions.
Developer and Validator Enhancements
Beyond the headline features, Glamsterdam incorporates a suite of improvements designed to benefit both developers and validators. These include the introduction of ETH transfer logs, a slot-number opcode for more precise timekeeping within blocks, an increased maximum contract size to accommodate more complex applications, a deterministic factory contract for predictable contract deployment, and new stack-manipulation instructions to enhance EVM capabilities.
On the consensus layer, changes include the adoption of forward-compatible data structures to facilitate future upgrades, the exclusion of slashed validators from proposing blocks to maintain network integrity, and an increase in exit and consolidation churn to improve validator management efficiency. The complete list of scheduled EIPs is integral to the Glamsterdam upgrade, each contributing to the network’s overall robustness and scalability.
The Road to Glamsterdam: A Phased Rollout
The Glamsterdam upgrade’s journey is marked by a phased rollout, beginning with extensive testing on various testnets before its eventual deployment on the Ethereum mainnet. The Sepolia testnet activation is scheduled for October 6, 2026, at 13:53:36 UTC. This carefully chosen date allows ample time for the broader ecosystem to adapt and prepare.
The agreed-upon deployment schedule, meticulously documented and reflected in updates to EIP-7773, outlines the critical milestones:
| Network | Epoch | Slot | UTC Time | UNIX Timestamp |
|---|---|---|---|---|
| Sepolia | 353,024 | 11,296,768 | 2026-10-06 13:53:36 | 1791294816 |
| Hoodi | TBD | TBD | TBD | TBD |
| Mainnet | TBD | TBD | TBD | TBD |
The activation times for the Hoodi testnet and the Ethereum mainnet will be communicated separately, following thorough consensus among client teams and further community engagement. This Sepolia announcement serves as a crucial precursor, detailing the immediate steps required for this testnet phase and does not signify a mainnet upgrade schedule.
Client Releases and Node Operator Responsibilities
As the Sepolia activation date approaches, client teams are diligently working on releasing versions that explicitly support the Glamsterdam upgrade. These releases are critical for node operators to ensure their infrastructure is compliant. The client release tables, both for the consensus layer and execution layer, will be updated regularly to reflect the availability of these compatible versions. It is imperative that operators consult these tables and select releases whose notes explicitly confirm support for the scheduled Sepolia activation.
For consensus layer clients, both the Beacon Node and the Validator Client must be updated. Specific instructions from client developers, such as Prysm and Teku, highlight important configuration changes, particularly regarding gas limits for block proposers. For instance, Prysm 7.2.0, while supporting the Sepolia fork, defaults to a 60 million gas limit post-activation. Validators aiming for a 200 million gas limit will need to configure this explicitly, as the --suggested-gas-limit flag will have no effect after the Gloas upgrade. Similarly, Teku 26.9.1 requires explicit configuration for higher gas limits via the --validators-builder-registration-default-gas-limit=200000000 parameter.
Execution layer client updates are equally vital. Operators using external block-building infrastructure should also heed any Glamsterdam-specific upgrade instructions provided by their tooling vendors.
Security and Bug Bounty
The Ethereum Bug Bounty Program has been extended to encompass the Glamsterdam specifications and associated EIPs. As soon as client implementations supporting the upgrade are released and added to the official client release tables, they become eligible for bounty claims. This proactive security measure underscores the Ethereum community’s commitment to a secure and robust network, encouraging thorough auditing and vulnerability reporting. Participants are encouraged to review the Ethereum Bug Bounty Program guidelines for detailed information on reward multipliers and reporting procedures.
Frequently Asked Questions (FAQ)
How do Ethereum network upgrades work?
Ethereum network upgrades are a community-driven process that requires explicit opt-in from node operators. Client developers coordinate protocol changes, and it is the responsibility of validators and non-staking nodes to update their software to align with the new rules. A node failing to adopt the updated software will be unable to participate in the upgraded network post-activation, highlighting the critical importance of coordinated updates for a successful upgrade. For a deeper understanding of Ethereum’s governance, resources such as talks by Tim Beiko provide valuable insights.
As an Ethereum mainnet user or ETH holder, is there anything I need to do?
For mainnet users and ETH holders, no immediate action is required. This announcement pertains specifically to the Sepolia testnet. A separate, comprehensive announcement will be issued detailing the Glamsterdam activation on the Ethereum mainnet. Those interested in observing the upgrade process live can participate in the scheduled online viewing party.
As a non-staking Sepolia node operator, what do I need to do?
Non-staking Sepolia node operators must update both their execution and consensus layer clients to releases that explicitly support the Glamsterdam activation before October 6, 2026, at 13:53:36 UTC. The client release tables will be continuously updated to reflect confirmed compatible versions.
As a Sepolia staker, what do I need to do?
Sepolia stakers must update their execution and consensus layer clients prior to the activation deadline. This includes ensuring both the beacon node and validator client are updated. Operators should meticulously review their client’s specific upgrade instructions, paying close attention to new ePBS duties and any necessary adjustments to validator or builder tooling.
As a Hoodi or mainnet node operator or staker, what do I need to do?
For operators and stakers on the Hoodi and mainnet networks, no immediate action is necessary based on this Sepolia announcement. Activation dates and compatible client releases for these networks will be communicated in subsequent announcements.
As an application or tooling developer, what should I do?
Application and tooling developers are advised to thoroughly review the EIPs scheduled for inclusion in the Glamsterdam upgrade. Post-activation on Sepolia, extensive testing of smart contracts and gas estimation mechanisms is paramount. Developers should assess the impact of changes to gas accounting, logs, opcodes, and client interfaces on their projects. The provided repricing impact guide is an essential resource for identifying contracts reliant on fixed gas assumptions and updating gas estimation strategies accordingly.
Why "Glamsterdam"?
The naming convention for Ethereum network upgrades follows a thematic approach. Execution layer upgrades are typically named after host cities of Devcon or Devconnect events, while consensus layer upgrades are named after stars. "Glamsterdam" is a portmanteau of "Gloas" (a star name for a consensus layer upgrade) and "Amsterdam," the host city of Devconnect in 2022, reflecting the combined nature of this significant network enhancement.
