Ethereum's Glamsterdam hard fork, now targeted for Q3 2026 after slipping from its original H1 window, represents the most significant structural overhaul of the network's block production pipeline since the Merge. The upgrade centers on two headliner proposals — EIP-7732 (Enshrined Proposer-Buil...
"If you create a 10,000 TPS EVM where its connection to L1 is mediated by a multisig bridge, then you are not scaling Ethereum." — Vitalik Buterin, Ethereum Co-Founder
Ethereum's Glamsterdam hard fork, now targeted for Q3 2026 after slipping from its original H1 window, represents the most significant structural overhaul of the network's block production pipeline since the Merge. The upgrade centers on two headliner proposals — EIP-7732 (Enshrined Proposer-Builder Separation) and EIP-7928 (Block-Level Access Lists) — that collectively aim to move block construction on-chain, enable parallel transaction execution, and raise the gas limit floor from 60 million to 200 million.
The stakes are measurable. Approximately 90% of Ethereum blocks are currently built off-chain through MEV-Boost, a relay-dependent system that concentrates block production among a handful of builders. Glamsterdam would replace this trust-based infrastructure with protocol-native mechanics, while simultaneously preparing the execution layer for a throughput target of 10,000 TPS at the base layer. The Ethereum Foundation confirmed the 200 million gas limit floor at its Svalbard interop in May 2026 and has named new Protocol cluster leads — Will Corcoran, Kev Wedderburn, and Fredrik — to shepherd the upgrade through testnet and mainnet deployment.
Ethereum's block production pipeline has operated on a de facto outsourced model since the Merge in September 2022. Under the current system, validators delegate block construction to specialized builders via MEV-Boost, software maintained primarily by Flashbots. The builders assemble transaction bundles optimized for Maximal Extractable Value, submit them through relays, and validators select the highest-paying block.
The numbers tell the story. Over 88% of Ethereum blocks — some sources cite upwards of 90% — are constructed through this off-chain relay system, according to data from relay monitoring tools and confirmed by the Ethereum Foundation. The relay market itself has consolidated: as of late 2025, Ultra Sound relay handled 32.3% of MEV-Boost payloads, Titan Relay captured 24.75%, BloXroute's two relays combined for approximately 26%, and Flashbots' own relay processed just 3.44%, according to relay tracker data.
This architecture creates three structural risks. First, relay operators become single points of failure — they can censor transactions or go offline, disrupting block production for the entire network. Second, capital-intensive builders dominate bidding, creating cyclical advantages where profitable builders outbid competitors, extract more MEV, and expand their bidding capacity. Third, the system depends on trust-based handshakes between validators, relays, and builders rather than cryptographic guarantees. Over 1 million active validators and approximately 37 million staked ETH (30.6% of circulating supply) depend on this infrastructure.
EIP-7732, the consensus-layer headliner, brings proposer-builder separation directly into Ethereum's protocol rules. Under the current system, the separation exists only as a social convention maintained by external software. Under ePBS, the roles become first-class protocol constructs.
The mechanism works as follows: proposers commit to a block header containing the winning builder's bid, while builders construct and submit the execution payload separately. A new validator responsibility — the Payload Timeliness Committee — attests to whether the builder delivered the payload on time. Builders register with on-chain identities and submit cryptographically signed bids, replacing the trust-based relay handshake.
Several structural changes follow. The payload propagation window extends from approximately 2 seconds to roughly 9 seconds, giving the network more time to process larger blocks safely. Relay operators — currently essential infrastructure — become optional. Validators can participate in block production without running third-party relay software.
The potential impact on MEV dynamics is significant. Researchers cited by Phemex estimate ePBS could reduce MEV extraction by up to 70%, though this figure should be treated as a modeled projection rather than a guaranteed outcome. What is more certain is that the proposal eliminates relay-mediated censorship: transactions that relays currently filter would flow through the protocol's native pipeline.
However, the academic literature introduces caveats. A June 2026 paper — "SoK: Current State of Ethereum's Enshrined Proposer Builder Separation" — notes that "even with an enshrined PBS system, there remains a risk that a few well-resourced builders could dominate the bidding market and monopolize block production." Exclusive order flows, where users route transactions directly to preferred builders, would persist under ePBS. The paper also finds that proposition rewards represent only approximately 12% of protocol-sponsored validator incentives, with the bulk arising from MEV and priority fees — a ratio ePBS does not directly alter.
The execution-layer headliner, EIP-7928, addresses a different bottleneck: Ethereum currently processes transactions sequentially. Each transaction executes one after another because nodes cannot predict which state — accounts, storage slots, contract data — a block will access until execution begins.
Block-Level Access Lists (BALs) solve this by requiring a complete map of all accounts and storage slots a block will touch before execution starts. With this map in hand, nodes can execute non-overlapping transactions simultaneously across CPU cores. Disk I/O, EVM execution, and post-state-root calculations become parallelizable.
The practical implications are quantifiable. According to Toni Wahrstätter, an Ethereum researcher, the average BAL size is approximately 35 KiB per block at 36 million gas, with worst-case sizes remaining below calldata worst-case limits. This means the data overhead of access lists is manageable relative to existing block constraints.
EIP-7928 is the enabling technology for Ethereum's gas limit expansion. Without parallel execution, raising the gas limit would simply increase the time required to validate each block, degrading network performance rather than improving it. With BALs, higher gas limits translate into higher throughput because validation work distributes across hardware resources.
The long-term throughput target is 10,000 TPS at the base layer, according to the Ethereum Foundation's Strawmap roadmap framework, though this figure encompasses multiple upgrade cycles extending to approximately 2029. Glamsterdam represents the first structural prerequisite.
Ethereum's block gas limit has already undergone one major expansion in the current cycle. In late 2025, validators signaled to raise the limit from 30 million to 60 million — a doubling that increased peak base-layer throughput from approximately 15 TPS to roughly 60 TPS. Over 513,000 validators supported the increase, which triggered automatically without a hard fork.
Glamsterdam sets the next target: a 200 million gas limit floor, representing a 3.3x increase from the current ceiling. The Ethereum Foundation confirmed this target at the Svalbard interop in May 2026, describing it as a "credible post-Glamsterdam target derived from convergence of ePBS, BAL optimizations, and EIP-8037 repricing."
The expansion is not a single event. It will be implemented gradually through validator signaling, the same mechanism used for the 30M-to-60M increase. The Foundation's language — "toward and beyond 200 million" — suggests this is a floor, not a ceiling.
For context, the previous gas-limit doubling in 2025 did not cause observable degradation in block propagation or validation times. The 200 million target, however, depends on parallel execution being functional — sequential processing at 200 million gas would increase worst-case block validation times to levels that could compromise network security.
Glamsterdam includes over 20 additional EIPs beyond the two headliners. Several address the economic and security risks of a higher gas limit:
EIP-8037 (State Creation Gas Cost Increase): Raises the cost of operations that create new state — new accounts, new storage slots — to prevent excessive state growth under higher block gas limits. Without this repricing, a 200 million gas block could create state entries at a rate that overwhelms node storage capacity over time.
EIP-7976 (Increase Calldata Floor Cost): Raises the minimum cost of calldata, the data field used by layer-2 rollups to post transaction data to Ethereum. This counterbalances the gas limit increase to prevent calldata-heavy blocks from consuming disproportionate resources.
EIP-7981 (Increase Access List Cost): Adjusts pricing for access list entries to reflect their true resource cost under the new parallel execution model.
EIP-7954 (Increase Maximum Contract Size): Raises the cap on deployable smart contract bytecode, accommodating more complex applications.
EIP-7778 (Block Gas Accounting without Refunds): Simplifies gas accounting by removing refund mechanics, making gas consumption more predictable for both users and block builders.
EIP-7843 (SLOTNUM opcode): Introduces a new opcode allowing smart contracts to read the current slot number, enabling time-aware contract logic.
Notable exclusions: EIP-7782 (6-second slots) was deferred due to conflicts with ZK proving requirements. FOCIL (Fork-Choice Enforced Inclusion Lists), a censorship-resistance mechanism, was pushed to the Hegotá upgrade, expected in late 2026 or Q1 2027.
The upgrade's scope is deliberate but bounded. Several structural challenges remain unaddressed:
Censorship at the builder level. ePBS eliminates relay censorship but does not prevent builders from selectively excluding transactions. FOCIL, designed to address this, is deferred to Hegotá. Until then, builder-level censorship — particularly of OFAC-sanctioned addresses — remains technically possible without protocol-level enforcement.
Builder market concentration. Moving PBS on-chain does not eliminate the economic advantages of large builders. As the SoK paper notes, well-resourced builders can maintain dominance through superior MEV extraction capabilities and exclusive order flow agreements.
Post-quantum readiness. Ethereum's current cryptographic primitives remain vulnerable to theoretical quantum attacks. Post-quantum upgrades are scoped for Hegotá and subsequent forks.
Native account abstraction. Full protocol-level account abstraction — enabling smart contract wallets as first-class citizens — is deferred to Hegotá, though Glamsterdam's architectural changes provide groundwork.
Glamsterdam restructures how economic value flows through Ethereum's block production pipeline. Under the current MEV-Boost system, value distribution follows a layered extraction model: users pay base fees (burned) and priority fees (to validators), MEV searchers extract additional value from transaction ordering, builders aggregate this value and bid for block inclusion, and relay operators facilitate the exchange.
By enshrining PBS, Glamsterdam formalizes the builder role within the protocol, potentially compressing the spread between MEV extraction and validator compensation. The elimination of relay intermediaries removes one extraction layer entirely.
The gas limit increase has separate economic effects. Higher throughput at the base layer reduces congestion-driven fee spikes, compressing the revenue validators earn from priority fees during periods of high demand. However, increased block space may attract more economic activity to the base layer — particularly activity currently executing on layer-2 networks — partially offsetting the per-transaction fee decline with higher volume.
For layer-2 operators, the data repricing EIPs (EIP-7976, EIP-7981) increase the cost of posting data to Ethereum, raising the operating expense of rollups. This creates tension: Ethereum scales its base layer while simultaneously increasing the cost of the infrastructure that layer-2s use for security.
The Ethereum Foundation's February 2026 roadmap post acknowledged this dynamic. Vitalik Buterin stated that the rollup-centric roadmap "no longer makes sense" in its original form, and that Ethereum is "now scaling directly on layer-1." The economic implication is a partial re-centralization of execution on the base layer, with layer-2s retaining relevance primarily for specialized use cases — privacy, application-specific environments, and regulatory-compliant execution contexts.
Glamsterdam is an infrastructure upgrade, not a product launch. It replaces off-chain trust assumptions with protocol-native mechanics, introduces the computational architecture for parallel execution, and sets a gas limit trajectory that targets 3.3x current capacity. The economic effects — compressed MEV relay rents, reduced congestion fees, higher L2 data costs — will materialize gradually as the gas limit scales through validator signaling.
The upgrade does not solve builder centralization, transaction censorship at the builder level, or post-quantum vulnerability. These are deferred to Hegotá and subsequent forks. The Ethereum Foundation has opted for sequential risk management: fix the relay dependency first, address censorship resistance second.
Whether the 200 million gas target translates into meaningful base-layer throughput gains depends on adoption patterns. More block space does not automatically produce more demand. What Glamsterdam provides is capacity — what fills it is a market question, not a protocol one.