Ethereum's Glamsterdam upgrade, due in the second half of 2026, is the network's first base-layer overhaul in years and what many developers call its biggest change since The Merge. It reworks how blocks are built to raise capacity and curb a hidden cost that eats into ordinary trades, arriving as the community that steers Ethereum sits in open revolt.
Ethereum is preparing Glamsterdam, an upgrade set to activate in the second half of 2026 that aims to make the blockchain itself faster and cheaper. Many developers call it the biggest change since The Merge, the 2022 switch from proof-of-work to proof-of-stake. That change cut the network's energy use by more than 99%. The name blends "Gloas," the consensus-layer component, with "Amsterdam," the execution-layer component.
What Glamsterdam changes
The upgrade makes two changes to how Ethereum handles transactions. The first reworks who controls the order inside a block. Right now a small group of specialist firms decides what goes into each block and in what order, routing blocks through middlemen and handing a few players the power to reorder transactions in ways that cost ordinary users money.
Glamsterdam builds a fairer process into Ethereum's own rules: whoever approves a block can no longer see or rearrange what is inside it, and the contents stay hidden until the block is final. This proposal is called enshrined proposer-builder separation, or ePBS (EIP-7732). The second change lets the network handle transactions that do not affect each other at the same time, adding capacity without pushing fees up — a proposal known as Block-Level Access Lists (EIP-7928).
Why it matters for DeFi
For anyone who trades on Ethereum, ePBS is the change to watch, because it targets a hidden cost baked into how the network runs. Holly Atkinson, Chief Product and Technology Officer at 1inch, called the upgrade "a credible step toward scaling L1 itself, not just via rollups" that reduces reliance on centralized block builders. She explained that most validators outsource block-building to a handful of specialized builders who see pending transactions and order them to extract value.
That practice reaches users as maximal extractable value, or MEV — a worse price when they trade on a decentralized exchange or run a token swap. Atkinson said ePBS shifts control back to the protocol that custodies user funds.
A community in revolt
Glamsterdam arrives at a tense moment. For much of the past year, the Ethereum Foundation has faced sustained criticism that it leaned too heavily on Layer-2 networks while letting the base layer stagnate. The pressure produced the most significant reorganization in the Foundation's history, including departures some called a brain drain. Even co-founder Vitalik Buterin publicly questioned whether many of today's Layer-2s still fit the network's model.
Price has not tracked that ambition. ETH traded around $1,879 on Wednesday morning, up roughly 5% on the day but down about 40% from a year earlier, when it changed hands near $3,140. It remains far below its all-time high of nearly $5,000, set in August 2025.
Source: TheStreet
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