Ethereum's Glamsterdam upgrade — a combined execution-layer (Amsterdam) and consensus-layer (Gloas) hard fork — entered its final devnet phase in mid-June 2026 with all planned Ethereum Improvement Proposals active. The upgrade targets a gas limit increase from approximately 60 million to 200 mil...
"We're working on devnets with all the EIPs in them right now. This is the last phase before we work on hardening and then shipping the testnets... probably the largest fork we've had since the Merge." — Parithosh Jayanthi, Ethereum Foundation Core Developer
Ethereum's Glamsterdam upgrade — a combined execution-layer (Amsterdam) and consensus-layer (Gloas) hard fork — entered its final devnet phase in mid-June 2026 with all planned Ethereum Improvement Proposals active. The upgrade targets a gas limit increase from approximately 60 million to 200 million per block, a 78% reduction in base-layer gas fees, and a theoretical throughput ceiling of 10,000 transactions per second. It is the network's most significant protocol change since the September 2022 Merge.
Two EIPs anchor the upgrade. EIP-7732 moves block building on-chain through Enshrined Proposer-Builder Separation (ePBS), replacing the off-chain MEV-Boost relay system that currently handles approximately 88% of Ethereum block production. EIP-7928 introduces Block-Level Access Lists (BALs), enabling parallel transaction execution and unlocking the higher gas limits without proportionally increasing validator hardware requirements. The Ethereum Foundation has set a mainnet target of Q3 2026, though public testnet deployments on Holesky and Hoodi must complete first. No firm date is locked.
The economic stakes are substantial. On devnet testing, multi-hop DeFi trades that previously cost $5–15 dropped to $0.30–0.80. Combined lending volume on Aave v4 and Morpho rose 140% in early simulations. Ethereum ETF weekly inflows averaged $180 million post-upgrade announcement, up from $95 million the prior quarter. However, the fee reduction carries a dual edge: address poisoning attacks surged 400% in test environments exploiting the lower transaction costs.
Glamsterdam restructures two foundational layers of Ethereum's operation simultaneously. On the consensus side, it overhauls how blocks are constructed and who builds them. On the execution side, it enables transactions within a single block to be processed concurrently rather than sequentially.
The upgrade bundles 10 EIPs formally scheduled for inclusion as of June 17, 2026, per EIP-7773. The two headline proposals — EIP-7732 and EIP-7928 — address distinct bottlenecks but are architecturally interdependent. ePBS extends the data propagation window from 2 seconds to approximately 9 seconds, creating the headroom necessary for validators to process larger blocks. BALs make those larger blocks computationally tractable by pre-declaring which state slots each transaction will access, allowing parallel reads and validation.
The name combines "Amsterdam" (execution layer, named after a previous Devconnect location) and "Gloas" (consensus layer, named after a star). The predecessor upgrade, Fusaka, shipped in December 2025. The planned successor, Hegotá, is tentatively slated for Q4 2026 to Q1 2027.
The problem ePBS addresses is structural. Today, 80–90% of Ethereum blocks are assembled off-chain via MEV-Boost, a relay-based system where specialized builders construct blocks and proposers (validators) select the highest-paying option. Approximately 30% of blocks currently comply with OFAC sanctions filtering through this relay infrastructure. Two to three builders control virtually all block production, according to multiple analyses.
EIP-7732 moves this builder market directly into the protocol. Key changes include:
The critical nuance: ePBS prevents builder centralization from spilling into the staking layer, but builder-level concentration may persist. Vitalik Buterin flagged this concern publicly, noting that the sophistication required to build blocks under ePBS with BALs may itself favor large-scale builders with low-latency infrastructure. Two proposed safeguards — FOCIL (Forward Obligatory Commitment to Inclusion Lists) and encrypted mempools — were deferred to the Hegotá upgrade.
Ethereum's current execution model processes transactions sequentially. Each transaction in a block must complete before the next begins, creating a fundamental throughput ceiling regardless of available hardware.
EIP-7928 introduces BALs — structured declarations of which accounts and storage slots a block's transactions will access. This serves three functions:
The gas limit increase from 60 million to 200 million — a 233% expansion — is only feasible because BALs prevent the parallelism from requiring proportional hardware upgrades. Without deterministic access lists, validating 200 million gas blocks would push hardware costs beyond what most solo validators could sustain. Node operators will, however, need to verify NVMe SSD IOPS capacity to handle the parallel read patterns.
The 78% fee reduction derives from three mechanisms, according to analysis by Deep Blue Alpha:
| Mechanism | Contribution to Fee Reduction | |---|---| | Gas limit expansion (60M → 200M) | ~45% | | Opcode repricing (EIP-7904) | ~22% | | MEV competition reduction (ePBS) | ~11% |
EIP-7904 recalibrates gas costs across opcodes based on modern hardware benchmarks. Several supporting EIPs adjust specific cost categories:
The net effect: basic ETH transfers become substantially cheaper, while state-heavy operations (contract deployment, storage writes) carry higher per-byte costs. This repricing philosophy deliberately shifts the economic burden from transaction volume toward state growth — a long-term sustainability measure.
As of June 17, 2026, EIP-7773 lists the following 10 proposals as Scheduled for Inclusion:
| EIP | Name | Category | |---|---|---| | EIP-7732 | Enshrined Proposer-Builder Separation | Consensus | | EIP-7928 | Block-Level Access Lists | Execution | | EIP-7708 | ETH Transfer Logging | Execution | | EIP-7778 | Remove Gas Refunds from Block Accounting | Execution | | EIP-7843 | SLOTNUM Opcode | Execution | | EIP-7954 | Maximum Contract Size Limit Raise | Execution | | EIP-7976 | Calldata Floor Cost Increase | Execution | | EIP-7981 | Access List Cost Adjustment | Execution | | EIP-8024 | SWAPN, DUPN, EXCHANGE Opcodes | Execution | | EIP-8037 | State Creation Gas Cost Increase | Execution |
Notable exclusions: EIP-7782 (6-second slots) was shelved due to the infrastructure burden on validators. FOCIL (EIP-7805, fork-choice inclusion lists) was moved to the Hegotá upgrade. Both decisions reflect the Ethereum Foundation's approach of shipping the parallelism and ePBS foundation first, then layering censorship-resistance mechanisms in a subsequent fork.
| Milestone | Date | Status | |---|---|---| | Soldøgn interop event | May 2, 2026 | Complete | | glamsterdam-devnet-5 | ~June 4, 2026 | Complete | | glamsterdam-devnet-6 | ~Mid-June 2026 | Complete/In Progress | | Final devnet phase (all EIPs) | Mid-June 2026 | Active | | Public testnets (Holesky, Hoodi) | TBD | Pending | | Mainnet activation | Q3 2026 (target) | Not locked |
The development cadence follows an aggressive schedule. The Ethereum Foundation's Soldøgn interoperability event on May 2 concluded with multi-client devnets running the full EIP slate. By mid-June, devnet-6 was undergoing testing with stability across multiple epochs as the primary success criterion.
Recent Ethereum hard forks have required two to four months of public testnet seasoning. Applying that precedent, a September to December 2026 mainnet window represents the firmer base case. Some staking providers cite an optimistic internal target of August 2026.
Fee revenue redistribution. Ethereum L1 validators currently derive significant revenue from MEV extraction via the relay system. ePBS is projected to reduce MEV extraction by up to 70%, according to preliminary estimates. This represents a direct revenue reduction for validators, partially offset by the expected increase in transaction volume from lower fees.
L1 vs. L2 dynamics. A 78% fee cut on L1 complicates the value proposition for Layer 2 networks, which exist partly because L1 was too expensive for small transactions. L2 transaction growth nonetheless increased 22% in post-upgrade modeling, suggesting that L2s retain advantages in latency and application-specific execution environments even as L1 costs decline.
Staking economics. Approximately 32.4% of ETH supply (39 million ETH, valued at roughly $100 billion) is currently staked, with annual yields near 2.7–3.2% APR. The validator set exceeds 1 million participants. Glamsterdam's introduction of the PTC validator duty adds a new responsibility to the staking stack, though it does not change the base reward structure.
DeFi activity. Early devnet data shows combined Aave v4 and Morpho lending volume increasing 140%. Multi-hop DeFi trades that cost $5–15 on current mainnet dropped to $0.30–0.80 in testing. This fee reduction puts Ethereum L1 in direct competition with Solana (~1,000–1,500 real-world TPS) and emerging chains like Monad (10,000+ TPS demonstrated).
ETF flows. Post-Glamsterdam announcement, Ethereum ETF weekly inflows averaged $180 million, compared with $95 million in the prior quarter.
Builder centralization persists. ePBS prevents builder dominance from contaminating the validator set, but sophisticated builders with low-latency infrastructure may still dominate block construction. The deferred FOCIL mechanism is intended to address this, but it ships in a later fork.
Attack surface expansion. Address poisoning attacks surged 400% in test environments exploiting lower fees. Lower transaction costs reduce the economic barrier to spam and griefing attacks. The calldata cost floor (EIP-7976) is designed to mitigate this, but effectiveness at scale is unproven.
Hardware centralization risk. While BALs keep hardware requirements theoretically accessible, the parallel execution model demands high-IOPS NVMe storage. Solo validators running consumer hardware may face degraded performance on 200 million gas blocks.
Timeline uncertainty. No mainnet date is locked. The Ethereum Foundation has missed prior upgrade targets. The realistic window spans Q3 to Q4 2026, a range that introduces planning uncertainty for protocols building around the upgrade.
Fee revenue compression. A 78% fee reduction, absent a proportional increase in transaction volume, compresses validator revenue and potentially reduces the network's burn rate under EIP-1559 mechanics. This may affect ETH's supply dynamics.
Glamsterdam represents Ethereum's most comprehensive base-layer restructuring since the proof-of-stake transition. The upgrade simultaneously addresses two long-standing criticisms: that L1 is too expensive for routine transactions, and that block construction is too centralized. The combination of ePBS and BALs is architecturally sound — moving block building on-chain while enabling the parallelism necessary to handle the resulting throughput increase.
The economic implications are material. A 78% fee cut, if it translates from devnet to mainnet, repositions Ethereum L1 as a direct competitor to alternative Layer 1 chains on cost. It also reshapes the L1-L2 fee dynamic, potentially compressing rollup margins while expanding the total addressable transaction market.
The open questions are equally material. Builder centralization persists even with ePBS. The attack surface expands with lower fees. Timeline uncertainty remains. These are engineering and governance problems, not theoretical ones, and the deferred FOCIL mechanism represents an explicit acknowledgment that Glamsterdam ships an incomplete solution to censorship resistance.
The data suggests the upgrade delivers its stated technical objectives. Whether the economic value flows to validators, users, or application builders depends on implementation details that will only become clear post-mainnet.