Ethereum's next hard fork, Glamsterdam, has entered generalized devnet testing as of late April 2026. The upgrade introduces two structural changes to the protocol: Enshrined Proposer-Builder Separation (ePBS, via EIP-7732) on the consensus layer, and Block-Level Access Lists (BALs, via EIP-7928)...
"I'm actually trying to do something even more ambitious: Create 'cypherpunk principled non-ugly Ethereum' as a bolt-on to the present-day system, in a way that's as tightly integrated and interoperable as possible, and then grow it over time." — Vitalik Buterin, Ethereum Co-Founder
Ethereum's next hard fork, Glamsterdam, has entered generalized devnet testing as of late April 2026. The upgrade introduces two structural changes to the protocol: Enshrined Proposer-Builder Separation (ePBS, via EIP-7732) on the consensus layer, and Block-Level Access Lists (BALs, via EIP-7928) on the execution layer. Together, they target a 3.3x increase in the block gas limit — from 60 million to 200 million — parallel transaction execution approaching 10,000 TPS on Layer 1, and an estimated 78% reduction in gas costs.
The fork also carries over a dozen supporting EIPs addressing gas repricing, state bloat, contract size limits, and opcode additions. According to the Ethereum Foundation's Checkpoint #9 update published April 10, 2026, progress is "slow but steady." Developers launched the first generalized devnet in late April, merging previously separate ePBS and BAL test environments into a single network. A June mainnet target remains on the table. Q3 is considered more realistic by protocol observers.
The stakes extend beyond throughput. Block building on Ethereum is dominated by two to three entities that produce roughly 90% of blocks, according to CryptoRank and Cointelegraph data from late 2024 through mid-2025. Glamsterdam's ePBS component moves the block auction into the protocol itself, replacing the off-protocol MEV-Boost relay system. Buterin has warned that ePBS alone does not automatically solve builder dominance, and has pushed for FOCIL (Fork-Choice Enforced Inclusion Lists) — now confirmed as the headliner for the subsequent Hegotá fork — as a complementary censorship-resistance mechanism.
Glamsterdam is the first Ethereum hard fork since Fusaka (December 2025). It addresses three structural bottlenecks simultaneously:
Throughput. The current gas limit of 60 million per block constrains Ethereum's base layer to approximately 1,000 TPS. Glamsterdam targets a 200 million gas limit, which — combined with parallel execution — is projected to support approximately 10,000 TPS. That is a 10x increase over current capacity.
Cost. Devnet testing has shown gas fee reductions of approximately 78% for both simple transfers and complex smart contract interactions, according to SpazioCrypto's reporting on the Glamsterdam devnet. The reduction stems from two factors: more gas capacity per block spreads demand across a larger supply, and parallel execution reduces per-transaction computation overhead.
Centralization. Ethereum's current block production operates through MEV-Boost, an off-protocol relay system maintained by Flashbots. This system has concentrated block production among a small number of builders. Glamsterdam enshrines the proposer-builder split directly into the consensus protocol, removing the dependency on external relays.
EIP-7732 formally separates two roles that currently overlap: the proposer (validator who selects the consensus block) and the builder (entity that assembles the execution payload containing transactions). Under the current system, this separation occurs off-protocol via MEV-Boost, where builders submit blocks to relays, which forward them to proposers.
Under ePBS, the hand-off is enshrined in the protocol. The proposer commits to a block header, and the builder fills in the execution payload. The data propagation window expands from approximately 2 seconds to roughly 9 seconds, according to the Ethereum Foundation's technical documentation. This expanded window accommodates higher transaction throughput and additional data blobs for Layer 2 networks.
The implementation complexity is substantial. As the Ethereum Foundation noted in Checkpoint #9: "Every part of the stack has to reason about 'partial blocks' and two-party coordination, a change that touches practically everything." The protocol must now handle disagreement or failure between proposers and builders — a scenario that did not exist in the simpler single-actor model.
Staking rewards under the current PBS system have increased by up to 60% compared to pre-PBS validators, according to an empirical study published by MDPI. ePBS aims to preserve these economics while eliminating relay trust assumptions.
EIP-7928 introduces Block-Level Access Lists — a metadata structure that records every account and storage slot accessed during block execution, along with post-execution values. This is the prerequisite for parallel transaction processing.
The problem it solves is straightforward. Ethereum's EVM currently executes transactions sequentially because it cannot know in advance which transactions will access overlapping state. If Transaction A and Transaction B touch different accounts and storage slots, they can run simultaneously. But without advance knowledge, the EVM defaults to serial execution.
BALs solve this by requiring blocks to declare their full state access pattern. Key characteristics from Ethereum Research data:
block_access_list_hash field containing the Keccak-256 hash of the RLP-encoded access listThe practical effect: nodes with multi-core processors can validate blocks significantly faster. A validator running a modern multi-core machine would process a 200M gas block in roughly the same time it currently processes a 60M gas block serially.
Glamsterdam includes two headliner EIPs and over a dozen supporting proposals. The confirmed and considered list from EIP-7773 (the hardfork meta-EIP):
| EIP | Description | Category | |-----|-------------|----------| | EIP-7732 | Enshrined Proposer-Builder Separation | Consensus (Headliner) | | EIP-7928 | Block-Level Access Lists | Execution (Headliner) | | EIP-7904 | General Gas Repricing | Gas Economics | | EIP-7976 | Increase Calldata Floor Cost | Gas Economics | | EIP-7981 | Increase Access List Cost | Gas Economics | | EIP-8037 | State Creation Gas Cost Increase | State Management | | EIP-7954 | Increase Maximum Contract Size (24 KiB → 32 KiB) | Developer Experience | | EIP-7778 | Block Gas Accounting Without Refunds | Gas Economics | | EIP-2780 | Reduce Intrinsic Transaction Gas | Gas Economics | | EIP-7688 | Forward-Compatible Consensus Data Structures | Consensus | | EIP-7708 | ETH Transfers Emit a Log | Observability | | EIP-7843 | SLOTNUM Opcode | EVM | | EIP-7997 | Deterministic Factory Predeploy | Infrastructure | | EIP-8024 | Backward-Compatible SWAPN, DUPN, EXCHANGE | EVM |
EIP-8037 merits attention. It introduces dynamic pricing that targets a state database growth rate of 100 GiB per year. The mechanism raises gas costs for creating new accounts and storage slots, directly addressing the long-term disk bloat problem that threatens node operator economics.
EIP-7954 raises the maximum contract size from approximately 24 KiB to 32 KiB, a 33% increase. Ecosystem developers have been vocal about this constraint, particularly teams building complex DeFi protocols and account abstraction wallets that push against current limits.
As of late April 2026, Glamsterdam has entered generalized devnet testing. The progression:
Client team status from All Core Developers Execution Call #232:
Projected timeline:
Glamsterdam's effects compound through the Layer 2 stack. The upgrade expands blob capacity — the dedicated data space rollups use to post compressed transaction data back to Ethereum. Current blob targets are 14-21 per block, with Glamsterdam targeting progressive increases toward 48 blobs by mid-2026.
At 48 blobs per block (approximately 2.6 MB per slot), Layer 2 rollups gain roughly 512 KB/second of data throughput, according to Ethereum Foundation estimates. This enables an estimated 12,000+ TPS across the combined L2 ecosystem.
Layer 2 fees have already dropped 70-95% since the Dencun upgrade introduced blobs in March 2024. Glamsterdam targets an additional 50-70% reduction in L2 posting costs. The mechanism: more blob capacity reduces bidding wars between rollups for data availability space.
The economic implication is direct. Rollups that currently pay $0.01-0.05 per transaction for data availability could see costs fall below $0.005. For high-volume rollups like Base, Arbitrum, and Optimism — each processing millions of daily transactions — the cumulative cost reduction is material.
Ethereum's block production market exhibits high concentration. Data from multiple sources paints a consistent picture:
ePBS addresses one layer of this problem by removing relays as trusted intermediaries. Under the current MEV-Boost system, relays can theoretically censor transactions or favor specific builders. Enshrining the auction removes this trust assumption.
However, Buterin has publicly noted that ePBS does not solve builder dominance itself. Builders with superior order flow access and MEV extraction algorithms will continue to win auctions. The complementary mechanism — FOCIL (EIP-7805), confirmed as the headliner for the Hegotá fork — would require a committee of 17 validators to independently propose inclusion lists, ensuring that any transaction can reach the chain through at least one of 17 different actors. Buterin stated this "gives guaranteed rapid inclusion" within one to two slots even in an "adversarial environment."
Glamsterdam is not a single feature upgrade. It is a concurrent overhaul of Ethereum's execution model, consensus architecture, and gas economics. The parallel execution capability introduced by BALs, combined with the consensus-layer restructuring of ePBS, addresses constraints that have defined Ethereum's operational ceiling since genesis.
The risk profile is commensurate with the scope. ePBS introduces two-party coordination into a system designed around single-actor block production. Every client team must implement and validate the new partial-block logic. As of late April 2026, not all clients have synced to head on the BAL devnet, and the ePBS devnet required stabilization before the generalized devnet could launch.
The economic value redistribution is worth tracking. If the 78% gas fee reduction materializes at mainnet, it compresses the fee revenue available to validators while increasing transaction volume. Whether the volume effect offsets the per-transaction fee reduction — and how MEV dynamics shift under enshrined PBS — will determine the post-Glamsterdam staking economics. The Ethereum Foundation has not published formal projections on this trade-off.
What is clear: Ethereum is attempting to close the throughput gap with newer Layer 1 chains while preserving its position as the settlement layer for a multi-rollup ecosystem. The data will show whether the architecture holds.