Market impact:
Glamsterdam is a slow-burn catalyst rather than a price trigger. Its benefits arrive at the infrastructure level and build over time as capacity rises. The near-term sentiment risk lies in the calendar: the upgrade has already slipped twice, and another delay after testnet trouble would likely weigh on the “Ethereum catch-up” narrative more than a clean test would lift it. Fund flows remain the better gauge of demand. Until Ether products show sustained inflows, traders are likely to treat upgrade milestones as background rather than reasons to chase ETH.
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Glamsterdam swaps Ethereum’s handshake deals with block-building middlemen for rules the network enforces itself, a real structural upgrade, but one whose payoff depends on a timeline that has already slipped twice.
Summary:
- The Ethereum Foundation scheduled Glamsterdam to activate on the Sepolia testnet on October 6 at 13:53 UTC; Hoodi and mainnet dates have not been set
- The headline change, ePBS (EIP-7732), writes the proposer-builder handoff into Ethereum’s protocol, replacing reliance on trusted relays used for around 88% of blocks today
- Block-level access lists (EIP-7928) let nodes process transactions in parallel, opening a path to raise the gas limit from about 60 million towards 200 million
- No action is required from ordinary ETH holders, but node operators and solo stakers face new validator duties
- Mainnet has slipped from the first half of 2026 to Q4 2026, and the Sepolia date moved from August 3 after test network bugs
- Hoodi testing is tentatively pencilled in for October 27
Ethereum’s next major upgrade, Glamsterdam, was scheduled to go live on the Sepolia test network on October 6 at 13:53 UTC, according to the Ethereum Foundation. And it did. It is the first public fork rehearsal for a change that rewrites how blocks are produced. Dates for the second testnet, Hoodi, and for mainnet have not yet been set. For most readers the name will mean little, so it is worth starting with the problem the upgrade is trying to fix.
The middlemen behind most Ethereum blocks
Every Ethereum block has a validator responsible for publishing it, known as the proposer. In practice, most proposers do not choose which transactions go into their block. That job has been handed to specialist firms called builders, who compete to assemble the most profitable ordering of transactions and bid for the right to have their block published. Proposers and builders are matched through middlemen called relays, using software known as MEV-Boost. Around 88% of Ethereum blocks are currently built this way, according to staking provider Everstake.
The arrangement works, but it rests on trust. A relay sits between two parties who do not trust each other, and nothing in Ethereum’s own rules guarantees that either side keeps its promise. It is a little like trading through a broker on a handshake: usually fine, but the protection comes from the broker’s reputation rather than from the exchange itself. That leaves a handful of relay operators with an outsized role in a network built to avoid exactly that kind of dependence.
What ePBS changes
Enshrined proposer-builder separation, or ePBS, is the centrepiece of Glamsterdam and is set out in a proposal known as EIP-7732. It moves the handoff between proposer and builder into the protocol itself. Builders gain an on-chain identity and submit signed bids, and a new committee of validators, the Payload Timeliness Committee, confirms whether the winning builder delivered its block contents on time. In effect, the exchange now guarantees the contract. Everstake notes the change also widens the window for passing block data around the network from roughly two seconds to around nine, which creates room for larger blocks.
Faster processing and bigger blocks
The second headline change, block-level access lists under EIP-7928, deals with speed. Ethereum nodes currently process transactions one after another because they cannot know in advance which parts of the network’s state a block will touch. Each block will now carry a map of every account and storage slot it uses, allowing nodes to read data and verify transactions in parallel. Developers see this as a credible route to lifting the network’s gas limit, a cap on how much work fits into each block, from about 60 million towards 200 million. Sepolia is being used to test capacity at that higher level, alongside separate gas repricing changes.
What it means for holders, and what it doesn’t
For everyday holders, the Ethereum Foundation says no action is required. The people who need to prepare are node operators and solo stakers, who face a new type of validator duty. The benefit is structural rather than immediate: less reliance on trusted middlemen, more capacity and potentially lower costs as the gas limit rises over time.
That is not the same as a reason to buy ether. A better network may support demand for ETH over the long run, but upgrades do not create buyers on a schedule, and spot Ether ETFs recorded three straight days of outflows at the start of October even with Glamsterdam approaching.
A timeline that has already slipped
The calendar deserves caution. Mainnet was originally pencilled in for the first half of 2026 and has since slipped to the fourth quarter. The Sepolia date was pushed back from August 3 after developer test networks ran into finalisation failures and a consensus bug. Consensus developer Potuz has also warned that cheap test ether could let an attacker spin up many disposable builders, win auctions with high bids and then fail to deliver blocks, a stress test the new design has to survive.
What to watch next
The first test is whether Sepolia runs and finalises cleanly over the coming days. After that, watch whether Hoodi holds its tentative October 27 slot, and when developers commit to a mainnet date on their regular All Core Developers calls. A clean run would strengthen the case for a fourth-quarter launch, while another slip would push the benefits into 2027. Either way, the practical takeaway is to treat Glamsterdam as a meaningful upgrade to how Ethereum works, and to judge any ETH price story on demand evidence such as ETF flows rather than on the upgrade calendar alone.
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Glamsterdam
The name of Ethereum’s next network upgrade, made by blending two words: Gloas and Amsterdam. Ethereum runs on two linked layers, and each gets its own name for every upgrade. The execution layer, which processes transactions and smart contracts, takes the name of a city that has hosted Devconnect, an Ethereum developer conference, so this half is Amsterdam. The consensus layer, where validators agree on the state of the chain, takes the name of a star, so this half is Gloas. Because both layers upgrade together, the two names are merged into one: Gloas + Amsterdam = Glamsterdam. The “glam” is a happy accident of the naming, not a description of the upgrade.
With that confirmed, the first entry needs a small tightening, so it no longer repeats the naming point loosely:
Network upgrade (hard fork)
A coordinated change to Ethereum’s rules that every node must adopt by a set date. Glamsterdam is the next one, following Fusaka, and the one after is already named Hegotá.
Testnet and mainnet
Mainnet is the live Ethereum network where real ETH moves. Testnets are copies that use valueless test ether, so developers can rehearse an upgrade safely before it touches real money.
Sepolia and Hoodi
Ethereum’s two main public testnets. Sepolia is widely used by app developers, while Hoodi is focused on validator and staking operations. An upgrade normally passes through both before mainnet.
Validator
A participant who stakes ETH to help secure the network, checking blocks and taking turns to publish them. Validators earn rewards for doing this correctly.
Proposer
The validator chosen to publish the block for a given time slot. Under today’s system, the proposer usually publishes a block someone else built.
Builder
A specialist firm that assembles transactions into the most profitable possible block, then bids for the proposer to publish it.
MEV (maximal extractable value)
The extra profit available from choosing which transactions go into a block and in what order. Competition for MEV is why specialist builders exist.
MEV-Boost and relays
MEV-Boost is optional software that connects proposers to builders. Relays are the middlemen inside that system, holding builders’ blocks and bids until a proposer commits. Around 88% of blocks currently flow through this setup.
EIP (Ethereum Improvement Proposal)
A numbered, public design document describing a proposed change to Ethereum. EIP-7732 (ePBS) and EIP-7928 (block-level access lists) are Glamsterdam’s two headline proposals.
ePBS (enshrined proposer-builder separation)
Building the proposer-builder relationship directly into Ethereum’s rules, so the protocol enforces the deal rather than a trusted relay.
Payload Timeliness Committee
A new group of validators created under ePBS. It confirms whether the winning builder released its block contents on time, giving the protocol a way to judge whether the builder kept its side of the deal.
Block-level access lists
A map attached to each block listing every account and piece of data the block touches. Knowing this in advance lets nodes process transactions in parallel rather than one at a time.
Gas limit
The cap on how much computing work fits into a single block. A higher gas limit means more transactions per block, which can ease congestion and fees.
Finalisation
The point at which a block is locked in and cannot be reversed without enormous cost. A test network failing to finalise is a red flag that the upgrade is not ready.
All Core Developers calls
Regular public meetings where Ethereum’s client teams agree on upgrade contents and dates. Mainnet timing for Glamsterdam will be set on one of these calls.
This article was written by Eamonn Sheridan at investinglive.com.