The Ethereum development community has officially announced the upcoming Glamsterdam network upgrade, a major technical milestone that continues the network’s long-term Layer 1 (L1) scaling roadmap. Following the successful deployment of the Fusaka upgrade in late 2025, Glamsterdam represents a critical pivot toward optimizing block production and state efficiency. The upgrade is scheduled to go live on the Sepolia testnet at epoch 353,024, corresponding to slot 11,296,768, which is set for October 6, 2026, at 13:53:36 UTC. While the testnet activation serves as a proving ground, dates for the Hoodi testnet and the eventual Ethereum mainnet deployment remain under deliberation by core developer teams.
The Glamsterdam upgrade derives its name from the synthesis of the Amsterdam execution layer project and the Gloas consensus layer upgrade, signaling a dual-track improvement to how Ethereum processes transactions. As the network continues to handle increasing transaction volume and data throughput, the necessity for robust, scalable infrastructure has become paramount. Glamsterdam introduces two landmark changes to the protocol: Enshrined Proposer-Builder Separation (ePBS) and Block-Level Access Lists (BALs). These features are designed to address the growing complexity of block validation and the mounting pressures of state growth.
A New Era for Block Production: Enshrined Proposer-Builder Separation
One of the most anticipated aspects of the Glamsterdam upgrade is the integration of EIP-7732, which brings the concept of Proposer-Builder Separation directly into the Ethereum consensus protocol. Previously, Ethereum relied on third-party middleware to manage the exchange between block builders—specialized entities that optimize transaction ordering—and proposers, who are the validators responsible for signing off on new blocks.
By enshrining this process, the protocol now natively handles the commitment of a builder to an execution payload, ensuring that the proposer includes the builder’s work without needing to trust external, centralized relay infrastructure. This architectural shift significantly reduces the potential for censorship and improves the overall resilience of the block-building supply chain.
Furthermore, ePBS introduces a structural separation between consensus validation and execution validation. Under the new rules, validators are granted additional time to verify execution payloads, which has historically been a bottleneck during periods of high network activity. A new "payload timeliness committee" will be responsible for attesting whether the builder has fulfilled their commitment and whether the associated blob data was published within the required window. This ensures that the network remains performant even as it processes more complex data structures.
Optimizing State and Performance: Block-Level Access Lists
To complement the improvements in block production, Glamsterdam introduces EIP-7928, which mandates the use of block-level access lists. As Ethereum’s state database grows, the efficiency with which nodes can read and write information has become a critical performance metric. Access lists provide a standardized way to track exactly which accounts and storage slots are touched by transactions within a specific block.
By enforcing these lists, the network enables client software to parallelize state access from disk. This allows for significantly faster transaction validation and more efficient computation of state roots. For node operators, this translates to a more manageable resource footprint; for the network at large, it creates a foundation for higher throughput without sacrificing the decentralization that defines Ethereum’s core value proposition.
Economic and Technical Adjustments
The Glamsterdam upgrade also includes a comprehensive series of gas pricing adjustments, most notably EIP-8037 and EIP-8038. These updates are intended to better align the cost of network resources with their actual consumption. EIP-8037 increases the cost of state creation, reflecting the long-term burden that new data puts on node operators, while EIP-8038 provides a more granular approach to state-access costs.
These changes are not merely cosmetic; they represent a significant shift in how Ethereum handles its "intrinsic" costs. Developers of decentralized applications (dApps) are strongly encouraged to review their smart contract architectures. Contracts that rely on hardcoded gas limits or fixed stipends may find themselves under-budgeted following the upgrade. The community has provided a "Glamsterdam Repricing Impact Guide" to assist developers in identifying potentially vulnerable contracts and updating their gas estimation logic before the upgrade hits the mainnet.
Beyond these core changes, the upgrade includes a suite of developer-friendly improvements, including the implementation of ETH transfer logs, a new slot-number opcode, and an increase in the maximum allowed contract size. These features are designed to simplify the development environment and provide more flexibility for complex smart contract interactions.
The Path to Mainnet: Coordination and Testing
The activation of Glamsterdam on Sepolia is a deliberate, staged process. As with all Ethereum upgrades, the responsibility for a successful deployment rests with the node operators, who must manually update their execution and consensus layer clients. A node that fails to upgrade will, by design, be unable to follow the chain post-activation, effectively falling off the network.
Client teams, including those managing Prysm and Teku, have already released versions compatible with the Sepolia upgrade. However, these releases come with specific configuration requirements. For example, some clients have adjusted their default gas limits to 60 million, but allow validators to manually configure a higher limit of 200 million via the keymanager API or specialized settings. Operators are urged to consult the specific release documentation for their chosen client to ensure they are fully prepared for the transition.
The Ethereum Foundation has emphasized that this announcement is strictly limited to the Sepolia testnet. The community is currently using the Sepolia environment to monitor the stability of the new code and to catch any edge-case bugs. A bug bounty program is currently active, offering rewards for identifying vulnerabilities in the Glamsterdam specifications or the updated client implementations. This program is a cornerstone of Ethereum’s security model, ensuring that as the protocol evolves, it does so under the scrutiny of the world’s leading security researchers.
Implications for the Broader Ecosystem
The shift toward ePBS and BALs represents a maturation of Ethereum’s strategy. Since the transition to Proof of Stake, the focus has moved from consensus stability to long-term scalability and decentralization. By moving away from external, trust-based middleware and toward protocol-native solutions, Ethereum is hardening its resistance to external interference.
For the average ETH holder or casual user, the upgrade is expected to be seamless and will not require any action. However, the cumulative effect of these changes will be felt in the coming years. By optimizing how the network manages its state and how it separates the roles of builders and proposers, Ethereum is positioning itself to support a wider array of high-frequency applications and Layer 2 scaling solutions.
The development process for Glamsterdam has been characterized by intense collaboration between client teams, researchers, and the wider developer community. The decision to name the upgrade "Glamsterdam"—a nod to the 2022 Devconnect conference held in Amsterdam—reflects the cultural importance of these gathering points in fostering the consensus necessary for such complex technical changes.
As the October 6, 2026, date approaches, the eyes of the blockchain industry will be on the Sepolia network. The success of this upgrade will not only dictate the timeline for the mainnet launch but will also serve as a proof-of-concept for the next generation of Ethereum’s architecture. For those looking to follow the progress, the Ethereum community has organized a series of technical briefings and a live, synchronized viewing of the upgrade as it occurs, underscoring the transparency and collective governance that remain the bedrock of the Ethereum network.
In summary, the Glamsterdam upgrade is a measured, high-stakes evolution of the Ethereum protocol. It balances the need for increased throughput with the necessity of maintaining a robust, decentralized, and censorship-resistant ledger. By addressing the fundamental mechanics of block production and state storage, the network is setting the stage for a future where decentralized finance and web3 applications can operate with even greater efficiency and reliability. As the Sepolia countdown begins, the focus remains on rigorous testing, clear communication, and the collective commitment to maintaining the integrity of the world’s most active programmable blockchain.
