This upgrade focuses on foundational changes to how Ethereum builds blocks, handles MEV (Maximum Extractable Value), and prepares its base layer-1 (L1) for sustained high throughput and fairer transaction processing. 

ethereum hit another ALL-TIME HIGH today.

2,595,176 transactions in 1 day.

this is only the beginning of ETH scaling.

glamsterdam update later this year will:

> reduce gas costs
> improve block-level execution efficiency
> reduce per-block processing overhead for nodes

ETH. pic.twitter.com/XVtRZH3gDf

— Joseph Young (@iamjosephyoung) January 15, 2026

Additionally, Ethereum launched its updated protocol roadmap on February 18, 2026, outlining new priorities across the Scale, Improve UX, and Harden the L1 tracks. This roadmap feeds directly into the upcoming Glamsterdam upgrade by consolidating scaling work under the unified Scale track, ensuring key components like higher gas limits, ePBS, repricings, and expanded blob capacity are developed in a coordinated way. 

At the same time, the Improve UX and Harden the L1 tracks support Glamsterdam’s goals by advancing native account abstraction, interoperability, security, and censorship resistance, helping the network scale without compromising usability or core Ethereum guarantees.

This article explains how Ethereum’s Glamsterdam upgrade, particularly the introduction of enshrined PBS, could reform MEV and improve layer-1 performance.

What is the Glamsterdam Upgrade?

Glamsterdam represents a coordinated set of protocol changes across Ethereum’s execution (EVM) and consensus layers. Unlike past upgrades that largely focused on layer-2 (L2) data availability, transaction batching, or cost reduction for rollups, Glamsterdam is a base-layer-centric upgrade – explicitly designed to improve the mechanics of block production, decentralization, and how MEV is captured and distributed.

Its name reflects a merge of the Gloas (consensus layer) and Amsterdam (execution layer) upgrade efforts into one coordinated hard fork aiming to strengthen the core of the protocol.

At its core, Glamsterdam includes two “headliner” features:

1. Enshrined Proposer-Builder Separation (ePBS) – EIP-7732
2. Block-Level Access Lists (BAL) – EIP-7928

These proposals work together to address long-standing structural issues with block formation, MEV centralization, and execution efficiency.

When is the Glamsterdam Upgrade scheduled?

The Glamsterdam upgrade is planned to take place in 2026, with Ethereum’s core developers targeting the first half of the year for its activation on the mainnet. This timing follows the successful implementation of the Fusaka upgrade in late 2025 and fits into Ethereum’s emerging biannual upgrade cadence, where major protocol updates occur roughly twice per year.

While the precise date hasn’t been formally confirmed, multiple protocol tracking sources and developer roadmaps currently place Glamsterdam in the early months of 2026, with May or June 2026 frequently cited as likely mainnet launch targets.

Why Ethereum wants to fix MEV and block building

MEV refers to the profit that can be earned by ordering, inserting, or censoring transactions within a block. In a blockchain like Ethereum, searchers (bots and algorithms) identify arbitrage, liquidation, and sandwich opportunities and compete to have their transactions included by block producers (validators or builders). MEV can distort fair execution ordering and generate revenue opportunities that are not shared equitably across participants.

In practice, MEV today often flows through off-chain relays such as Flashbots MEV-Boost, where specialized builders assemble blocks and propose them to validators in exchange for bids, creating centralization pressure at the relay and builder layers.

This architecture has led to criticisms that:

• A small set of builders and relays capture the majority of MEV revenue.
• Validators increasingly depend on trusted off-chain infrastructure.
• Transaction ordering and inclusion fairness can vary with relay power.
• Centralization pressures can undermine decentralization goals.

Glamsterdam targets these issues by bringing crucial incentives and processes into the protocol itself, a shift from off-chain coordination toward on-chain enforcement.

Enshrined Proposer-Builder Separation (ePBS): A protocol-level MEV solution

The standout feature of the Glamsterdam upgrade is Enshrined Proposer-Builder Separation (ePBS), formalized in Ethereum Improvement Proposal 7732 (EIP-7732). Unlike the current reliance on external MEV-Boost relays, ePBS enshrines the separation of roles directly into Ethereum’s consensus layer.

What does ePBS do?

Under ePBS:

• Builders compile transactions into complete blocks, including MEV-rich orderings.
• Proposers (validators) blindly select among sealed block candidates based on promised rewards (bids), without seeing transaction contents.
• The protocol enforces that proposers can’t reorder or tamper with the transaction lists in the selected blocks.

By having proposers select sealed blocks rather than build them, ePBS aims to:

• Limit centralized control by reducing reliance on third-party MEV relay services.
• Improve fairness by separating block construction from selection logic.
• Reduce censorship risk because validators can no longer alter ordering after a builder’s commitment.
• Make MEV revenue distribution more transparent rather than opaque and relay-controlled.

Why Enshrinement Matters

In the current MEV-Boost world, relays play a critical role in matching builders with validators. This creates de facto centralized chokepoints – even if the underlying blockchain remains decentralized. Enshrining Proposer-Builder Separation into the consensus layer means:

• Block selection logic is part of Ethereum’s core rules, not an external agreement layer.
• Validators don’t need to trust external software for MEV participation.
• The network itself defines how blocks are selected and rewards are distributed.

Bringing these mechanisms into protocol code reduces the “black box” nature of MEV coordination and aligns incentives with Ethereum’s decentralization ethos.

Detailed mechanics of ePBS

While the high-level concept of ePBS is straightforward, its execution involves careful engineering to preserve security and liveness.

Sealed block commitments

Builders don’t submit full block contents first. Instead, they:

• Create a sealed block commitment (often cryptographically bound but without exposing contents);
• Submit bids to validators proposing expected rewards;
• Validators collect these sealed bids and choose the most economically favorable one.

Once a block is selected, only then are contents revealed, ensuring proposers have no ability to reorder or manipulate data after seeing it.

Countering the ‘free option problem’

Academic research into ePBS identifies a potential risk known as the “free option problem,” where builders could withhold revealing a committed block if market conditions shift unfavorably, effectively gaining a free choice to abandon their commitment without significant penalty.

Flashbots on ePBS & the “Free Option Problem” – A MEV Perspective (#Glamsterdam)

Christopher presented risks in #ePBS related to economic exploits and propagation delay, discussed problems and solutions.

Summary:
ePBS introduces two deadlines via PTC:

⏱️ Payload: 4s
🫧 Blob:… pic.twitter.com/xvDO4GqcbB

— Pooja Ranjan | ranjan.eth (@poojaranjan19) July 24, 2025

To mitigate this, proposed solutions include:

• Shortening the option window to limit exploitation.
• Introducing penalties for builders who fail to deliver on commitments they bid on.
• Using cryptographic commitments that enforce block revelations after proposers accept them.
• Requiring collateral or bonding, which builders forfeit if they do not reveal blocks.
• Multi-builder fallback systems, allowing proposers to quickly switch to backup builders if the primary builder fails.
• Improved timing constraints to ensure payloads are delivered earlier in the slot.

There are also discussions around auction design improvements, such as sealed-bid auctions, reputation systems, or builder scoring, which could reduce incentives to strategically withhold blocks. Some proposals further suggest distributed builder markets to reduce reliance on a small number of dominant builders.

These refinements remain part of ongoing academic research, simulation testing, and protocol discussions as Ethereum developers finalize the ePBS design. The goal is to preserve MEV efficiency and proposer revenue while maintaining credible neutrality, decentralization, and reliable block production as Ethereum continues evolving toward a more robust PBS architecture.

Potential MEV Dynamics Under ePBS

Embracing ePBS will change how MEV is captured and distributed:

• Validators may receive larger portions of MEV revenue without running builders themselves.
• Builders compete openly in sealed auctions rather than via trusted relays.
• Searching strategies might shift, as sealed block auctions limit visible transaction ordering signals.

Some early research suggests that while ePBS can reduce some centralization risks, it may also concentrate builder profits unless the broader market structure remains competitive.

Block-level access lists: Improving execution efficiency

Alongside ePBS, Glamsterdam includes Block-Level Access Lists (BAL, EIP-7928), a proposal to streamline execution layer performance.

NEW EIP TO SCALE THE ETHEREUM L1 🚨

EIP-7928: Block-Level Access Lists (BALs)
parallel disk reads & parallel execution pic.twitter.com/jch5wdNH7q

— Uttam (@uttam_singhk) May 16, 2025

What are access lists?

Traditionally, an Ethereum block discovers which parts of the state it will access as transactions execute. This incremental discovery means nodes must read and verify storage and account data dynamically – a process that can be inefficient at scale.

Block-Level Access Lists propose that a block explicitly declares in advance which state it will read or write. Clients can preload this information into cache, enabling:

• Faster execution and validation
• Reduced I/O overhead
• Better predictability for transaction costs
• Laying groundwork for parallel execution approaches in the future

By knowing state access patterns ahead of time, nodes can better optimize resource usage and improve throughput, especially important as rollups and L2 traffic continue to grow.

This efficiency in data access reduces friction for nodes and prepares Ethereum’s base layer for higher demand without sacrificing security or decentralization.

Why Glamsterdam matters for layer-1 performance

Ethereum’s long-term roadmap, sometimes referred to as Surge, centers on scalability without compromising decentralization. Unlike past upgrades that shifted burden to layer-2 rollups, Glamsterdam focuses on making the layer-1 base layer itself more efficient, fair, and resilient.

Execution efficiency gains

By optimizing how blocks declare and access state, the execution layer becomes more predictable. BAL may reduce execution latency and resource load at the node level, creating a smoother environment for complex transactions. This lays groundwork for higher transactions per second (TPS) on layer-1 and smoother interaction with layer-2 ecosystems.

Reduced MEV centralization

MEV, if left unmanaged, concentrates power among a few builders and relays, creating structural centralization risks that can undermine consensus decentralization. ePBS helps remove trusted intermediaries from the MEV market and ensures that block rewards are decided by protocol rules rather than by off-chain agreements.

Censorship resistance and decentralization

Under the current model, builders and relays can exercise subtle forms of censorship by excluding or delaying certain transactions. ePBS weakens these vectors by requiring sealed blocks and blind proposer selection, leading to a more censorship-resistant and trust-minimized block production process.

Preparation for future scaling elements

Glamsterdam doesn’t solve all scaling challenges on its own, but it provides critical foundational pieces:

• Clean separation of responsibilities in block production helps future parallelization efforts.
• Better state access mechanics support predictable execution for higher throughput.
• Reduced reliance on off-chain touchpoints improves security assumptions.

These groundwork improvements feed into later upgrades such as Hegota, which targets state bloat and node efficiency with Verkle Trees and support for stateless clients.

Risks and open questions

While Glamsterdam’s design is powerful, it introduces technical complexities:

Free option and liveness risks

Research indicates that ePBS could unintentionally introduce a “free option” for builders to withhold blocks under certain market conditions, potentially harming network liveness or execution timeliness.

Ethereum’s community is actively exploring mitigation strategies, including punishment mechanisms and structural refinements to reduce exploitability.

Economic concentration

Some formal studies suggest that ePBS might increase profit concentration among efficient builders if not balanced by a competitive ecosystem, raising questions about long-term decentralization incentives.

These analyses highlight that while protocol changes can reduce certain centralization vectors, they also reshape economic incentives in complex ways.

Client and implementation hardening

Integrating ePBS and BAL requires coordinated updates across all major clients (execution and consensus) and extensive testing on public testnets before mainnet activation, ensuring safety and compatibility across the diverse Ethereum ecosystem.

Broader implications for DeFi and dApps

For decentralized finance (DeFi) protocols, NFTs, and broadly distributed applications, Glamsterdam heralds several important shifts:

Improved predictability

Reduced MEV friction and more transparent block construction can lead to lower incidental slippage and fewer unexpected front-running events. This benefits traders, liquidity providers, and automated DeFi strategies.

Lower barriers to participation

As ePBS removes dependency on external relays, validators can participate without complex relay integrations, broadening the base of participants and strengthening decentralization.

Clearer fee signals

Block-Level Access Lists could lead to more stable and predictable gas pricing by aligning execution costs with declared resource usage, benefiting developers and end users alike.

Stronger foundation for real-world use cases

As Ethereum scales both in terms of performance and fairness, it becomes a stronger foundation for real-world asset tokenization, institutional DeFi, and interoperable financial tooling,  helping it compete with both centralized infrastructure and alternative blockchains on security and composability.

A turning point for Ethereum’s base layer

The Glamsterdam upgrade represents a significant evolution in Ethereum’s design philosophy. Moving from supplementary improvements to foundational architectural reform, it embeds fairness, performance, and trust minimization deep into the protocol.

By making Proposer-Builder Separation a core rule, reducing execution friction via Block-Level Access Lists, and preparing the network for richer future scaling work, Glamsterdam seeks to secure Ethereum’s role as a globally robust layer-1 settlement layer.

If successful, it will balance decentralization, security, and performance more effectively, a key step for Ethereum as it continues to grow under increasing demand from users, developers, institutions, and large-scale decentralized applications.