Ethereum's Glamsterdam hard fork — the network's largest protocol change since the Merge — enters its final devnet phase with a target activation in Q3 2026. The upgrade combines two headline EIPs: Enshrined Proposer-Builder Separation (EIP-7732) and Block-Level Access Lists (EIP-7928), alongside...
"There's a new chapter starting for the Protocol cluster. We're welcoming new leads and coordinators, and continuing our work toward Glamsterdam, Hegotà, and the Strawmap." — Will Corcoran, Ethereum Foundation Protocol Lead
Ethereum's Glamsterdam hard fork — the network's largest protocol change since the Merge — enters its final devnet phase with a target activation in Q3 2026. The upgrade combines two headline EIPs: Enshrined Proposer-Builder Separation (EIP-7732) and Block-Level Access Lists (EIP-7928), alongside eight additional proposals that collectively raise the block gas limit from 60 million to 200 million, restructure gas pricing, and enable parallel transaction execution. The Ethereum Foundation confirmed the timeline shift from June to Q3 during a May 12 blog post, citing complexity of cross-client ePBS implementation as the primary bottleneck.
The stakes are material. Approximately 88% of Ethereum blocks are currently built through external MEV-Boost relay networks, concentrating block construction among a small number of sophisticated builders. Research from the Flashbots Collective estimates ePBS could reduce MEV-related losses for ordinary users by up to 70%. The 200 million gas target, if achieved, would push throughput toward 10,000 transactions per second — roughly 10x current capacity — while an estimated 70% reduction in Layer 2 settlement costs could intensify fee competition among rollups including Arbitrum, Optimism, and Base.
The upgrade arrives amid organizational upheaval at the Ethereum Foundation, where at least eight senior staff departed in 2026 under a "Lean Ethereum" restructuring that included 19 layoffs. New protocol leads Will Corcoran, Kev Wedderburn, and a developer identified only as Fredrik now oversee the upgrade. The last major fork, Fusaka (December 2025), executed with zero downtime but triggered a Prysm client bug that caused 248 missed blocks across 42 epochs and cost validators 382 ETH (~$1 million) — a precedent that weighs on Glamsterdam's multi-client testing timeline.
Glamsterdam simultaneously updates Ethereum's Execution Layer (Amsterdam) and Consensus Layer (Gloas), following the dual-naming convention established by Shapella in 2023. Ten EIPs are scheduled for inclusion:
| EIP | Name | Layer | Effect | |-----|------|-------|--------| | 7732 | Enshrined PBS | Consensus | Moves block building into protocol rules | | 7928 | Block-Level Access Lists | Execution | Enables parallel transaction processing | | 7976 | Increase Calldata Floor Cost | Execution | Affects rollup batch posting costs | | 7981 | Increase Access List Cost | Execution | Recalibrates EIP-2930 pricing | | 8037 | State Creation Gas Cost Increase | Execution | Anti-state-bloat mechanism | | 7954 | Increase Max Contract Size | Execution | Raises limit from 24 KiB to 64 KiB | | 7778 | Block Gas Accounting Without Refunds | Execution | Simplifies gas economics | | 8024 | SWAPN/DUPN/EXCHANGE Opcodes | Execution | Stack manipulation tools | | 7843 | SLOTNUM Opcode | Execution | Exposes slot number to contracts | | 7708 | ETH Transfer Logging | Execution | Emits logs for native ETH movements |
Two proposals were explicitly deferred. Fork-Choice Inclusion Lists (FOCIL, EIP-7805) were pushed to the successor upgrade Hegotà to avoid untested interaction complexity with ePBS. Six-second slots (EIP-7782) were excluded due to conflicts with ZK-proving timelines and insufficient client maturity.
According to Chainstack's infrastructure analysis, "Glamsterdam touches far deeper consensus code than Fusaka did," requiring mandatory updates across all five execution clients (Geth, Nethermind, Besu, Erigon, Reth) and six consensus clients (Lighthouse, Prysm, Teku, Nimbus, Lodestar, Grandine).
EIP-7732 is the most structurally significant change since Ethereum moved to proof-of-stake. Currently, approximately 88% of Ethereum blocks are built using MEV-Boost, an off-protocol relay system where specialized builders construct blocks and proposers (validators) select them through competitive auctions.
The system works, but it concentrates power. According to a January 2026 analysis, five builders control 96.7% of all MEV blocks, with the top builder holding a 27.9% market share. Two builders alone account for 95.7% of the MEV-Boost market. This concentration creates censorship risk and systemic fragility.
ePBS moves this process on-chain. The mechanism splits block production into two distinct protocol-level roles:
The two-phase design introduces a new beacon chain message type — the execution payload envelope — separating consensus attestation from execution payload. Data propagation windows expand from approximately 2 seconds to 9 seconds, accommodating larger blocks.
For validators, this means a new attestation duty (PTC participation). For infrastructure operators, MEV-Boost relays become optional rather than essential. Smart contracts require no modifications — ePBS operates at the consensus layer and does not change the EVM.
The Flashbots Collective estimates that ePBS could reduce MEV-related losses for ordinary users by up to 70%, primarily through a more competitive and transparent auction mechanism. That figure remains a projection; actual impact will depend on builder behavior post-activation.
EIP-7928 addresses a fundamental bottleneck: Ethereum currently processes transactions sequentially. Each transaction must complete before the next begins, regardless of whether they touch different parts of state.
Block-Level Access Lists (BALs) allow the network to pre-declare which accounts and storage slots a block will access. This mapping enables client software to execute independent transactions across multiple CPU cores simultaneously.
The practical ceiling of this optimization is the 200 million gas limit target. Current hardware can support sequential execution at 60 million gas. Parallel execution under BALs is the architectural prerequisite for processing 3.3x more gas per block without proportionally increasing block times.
BALs also support stateless client reconstruction — a long-standing goal on Ethereum's roadmap — by making state access patterns explicit and verifiable without requiring full state storage.
Glamsterdam restructures Ethereum's gas cost model through EIP-8007 and its constituent proposals:
Cheaper (computation):
More expensive (state creation):
The repricing philosophy aligns gas costs with actual resource consumption on modern hardware. Computation has become cheap; persistent state storage remains expensive. Contracts, relayers, and wallets with hardcoded gas values will need testing against Glamsterdam testnets (Sepolia, Hoodi) before mainnet activation.
EIP-7708 adds native ETH transfer logging, emitting events in standard ERC-20 Transfer format. This enables tracking native ETH movements through eth_getLogs queries rather than requiring trace methods — a meaningful infrastructure simplification for block explorers, analytics platforms, and compliance tooling.
The gas limit expansion from 60 million to 200 million is not automatic. It requires validators to signal support, similar to how the network previously raised limits from 36 million. The Ethereum Foundation characterized 200 million as a "credible post-Glamsterdam target" rather than a guaranteed outcome.
The increase has infrastructure implications:
For context, Ethereum currently supports approximately 885,000 active validators with 41.04 million ETH staked (34% of circulating supply), earning an average APR of 2.64%. A gas limit increase that destabilizes smaller validators could concentrate the validator set further.
The throughput target of approximately 10,000 TPS at 200 million gas represents a 10x increase from current levels. Whether this materializes depends on BAL adoption, client optimization, and the distribution of transaction types across blocks.
Glamsterdam's calldata repricing and expanded blob capacity pathway create direct economic consequences for Layer 2 rollups.
Settlement cost projections indicate an approximately 70% reduction for L2s posting data to Ethereum. For rollups like Arbitrum, Optimism, and Base — which already compete on sub-cent transaction fees — this compression flows through to end-user pricing and further erodes the economic moat of any single L2.
The ePBS propagation window expansion also creates a path for future blob capacity increases through Blob Parameter Only (BPO) forks, potentially without requiring full hard forks. This is significant because Fusaka's PeerDAS technology (December 2025) already increased blob capacity eightfold; additional expansion could make Ethereum's data availability layer cost-competitive with dedicated DA networks like Celestia and EigenDA.
Contract size limits also increase (24 KiB to 64 KiB for deployed code; 48 KiB to 128 KiB for initcode under EIP-7954), removing a constraint that has forced developers to split complex protocols across multiple contracts.
Glamsterdam's technical ambition coincides with significant organizational change at the Ethereum Foundation. At least eight senior staff departed in 2026, including protocol coordination lead Tim Beiko, researcher Barnabe Monnot, and developer Alex Stokes. The Foundation laid off 19 employees as part of a "Lean Ethereum" strategy that reframes the organization as a network steward rather than its owner.
The new protocol leads — Corcoran, Wedderburn, and Fredrik — inherit the most complex upgrade since the Merge. Fusaka's Prysm bug, which caused 248 missed blocks and $1 million in validator losses despite zero downtime, demonstrated that even successful forks carry execution risk. Glamsterdam's deeper consensus-layer changes raise the complexity bar.
Development milestones as of July 2026:
The successor upgrade Hegota is already in scoping, targeting Verkle Trees (reducing node storage requirements by approximately 90%) and FOCIL. The Foundation's quantum-resistant long-term roadmap, the Strawmap, continues in parallel.
Glamsterdam is Ethereum's attempt to solve three problems simultaneously: MEV centralization through ePBS, throughput limitations through parallel execution, and gas mispricing through cost restructuring. The 200 million gas limit target, if realized, would fundamentally alter Ethereum's position relative to both competing L1s and its own L2 ecosystem.
The economic implications extend beyond Ethereum. A 70% reduction in L2 settlement costs, combined with cheaper calldata and expanded contract sizes, shifts the cost structure for every protocol building on Ethereum infrastructure. For validators running 885,000 nodes with 41 million staked ETH, the upgrade introduces new duties (PTC attestation) and new hardware requirements that will test the network's decentralization commitments.
The question is not whether these changes are technically sound — devnet testing suggests they are. The question is whether a reorganized Foundation, running its most complex multi-client upgrade with new leadership, can execute without a repeat of Fusaka's Prysm incident at a scale where the consequences would be significantly larger. Public testnet performance in the coming weeks will provide the first concrete data point.