Ethereum's Glamsterdam Upgrade Hits Hoodi Testnet: What Changes on October 26

Ethereum took its next upgrade step on October 26, 2026, as Glamsterdam activated on the Hoodi testnet. Hoodi is the testing ground where major Ethereum upgrades are trialed before they are considered for mainnet, so an activation there is a milestone, not a finish line. The headline changes in Glamsterdam include a jump in the gas limit toward 200 million, proposer-builder separation, and access lists — three pieces that together aim to make the network handle more activity with fairer ordering and more predictable execution.

For everyday users, the honest summary is simpler: nothing changes on mainnet today. Testnet activations exist precisely so developers can find problems before real money is at stake. But the direction matters, because Ethereum's upgrade history shows that what survives testnet usually shapes the network for years. Understanding Glamsterdam now, while it is still being tested, is the best way to judge later claims about speed, fees, and fairness when mainnet discussions begin.

What Glamsterdam actually contains

Glamsterdam bundles several Ethereum Improvement Proposals into one upgrade. The most talked-about is the gas limit increase toward 200 million, which would let each block include substantially more computation than today. In practice, a higher gas limit means more transactions and more complex operations per block, which can ease congestion during busy periods. It does not automatically mean lower fees — fees depend on demand as well as capacity — but more room per block gives the network more headroom when demand spikes.

Proposer-builder separation, often shortened to PBS, changes how blocks are assembled. Today, the validator proposing a block has a large role in choosing and ordering its transactions. PBS splits that job: specialized builders assemble blocks, and proposers choose among them. The goal is to reduce the advantage of sophisticated, well-connected block producers and to make transaction ordering more competitive and transparent. Access lists, the third major piece, let transactions declare in advance which parts of the state they will touch, which can make execution more efficient and predictable.

Why the Hoodi testnet matters

Hoodi exists to catch what unit tests cannot: the interactions between clients, validators, and real network conditions. An upgrade can look perfect in isolation and still break when thousands of nodes run it together, which is why Ethereum's process runs major upgrades on testnets first and watches them for weeks. Developers monitor for missed blocks, client disagreements, slow finality, and edge cases in the new features. A clean Hoodi run builds confidence; problems found there are successes of the process, not failures of the upgrade.

It is also worth being precise about what testnet success proves. It proves the software runs under test conditions, not that mainnet economics will behave a particular way. Gas limit increases, for example, raise real questions about hardware requirements for node operators and about state growth, which only become fully clear over time. Testnet data informs those debates, but the mainnet decision will weigh trade-offs that no testnet can settle alone. Anyone promising exact fee or speed outcomes from Glamsterdam today is getting ahead of the evidence.

The 200M gas limit: what it can and cannot do

A gas limit near 200 million would be a major capacity increase for Ethereum's base layer. During demand surges — token launches, market volatility, popular NFT or DeFi events — blocks fill up and users compete on fees. More gas per block means more of that demand fits, which can soften fee spikes. But capacity is only half the fee equation. If demand grows to fill the new space, fees can stay high even with bigger blocks. Layer-2 networks also complicate the picture: much of Ethereum's everyday activity already happens on rollups, so base-layer capacity matters most for settlement, large DeFi operations, and periods when everyone wants mainnet at once.

Proposer-builder separation and fairer ordering

Transaction ordering matters because the order of trades inside a block can be worth money — the value known as MEV, or maximal extractable value. When the same party both builds and proposes blocks, sophisticated players can capture more of that value. PBS aims to level the field by letting many builders compete to assemble the best block while proposers pick the most valuable valid option. In theory, competition among builders returns more value to proposers and, indirectly, to stakers, while making the process more open to scrutiny.

The realistic expectation is improvement, not perfection. PBS changes incentives and structure, but MEV does not disappear, and new forms of centralization can appear among builders themselves. That is one reason the upgrade is being tested carefully: researchers want to see how builder markets behave in practice, how many independent builders participate, and whether the separation actually delivers the fairness gains it promises. Traders should treat PBS as infrastructure progress, not as a reason to expect a price move.

What this means for ETH holders and traders

On October 26, Ether traded near $2,310 to $2,330, with support around $2,280 to $2,300 and its 200-day average near $2,320. That is a market sitting almost exactly on its long-term average, which is a useful reality check against upgrade hype: Glamsterdam's testnet activation did not, by itself, drive a price breakout, and it should not be traded as if it did. ETH's near-term direction remains tied to the same macro forces moving Bitcoin — the October 27-28 FOMC meeting, inflation data, and risk appetite — far more than to testnet milestones.

• Testnet activation is not a mainnet launch date — no mainnet date is set by a Hoodi activation alone.
• Upgrade benefits arrive gradually as wallets, apps, and infrastructure adopt the new features.
• Gas limit increases help capacity but do not guarantee lower fees if demand rises too.
• PBS improves ordering structure but does not eliminate MEV or guarantee fairer outcomes overnight.
• For traders, ETH's price drivers this week remain macro: the Fed, inflation, and ETF flows.

Testnet versus mainnet: how to follow what happens next

The sensible way to follow Glamsterdam is to watch for three things: how long Hoodi runs cleanly, what issues client teams report and fix, and when core developers start discussing mainnet timing. Each stage has its own signal. A long, stable testnet run supports a mainnet proposal; repeated issues push timelines out, and that delay is the system working, not a crisis. Traders interested in Ethereum's infrastructure can also compare how upgrades affect different parts of the market — for example, how funding-rate arbitrage conditions shift when network capacity changes, or how centralized versus decentralized venues handle periods of congestion differently. The glossary covers terms like gas, MEV, and testnet for readers new to the topic.

For builders and long-term observers, Glamsterdam is genuinely interesting: a bigger gas limit, a new block-building structure, and smarter execution tooling point toward a more capable base layer. For traders, the honest takeaway is patience. The upgrade's value will show up over months in network behavior, developer activity, and fee patterns — not in a single day's candle. Watching the testnet phase with that timeframe in mind is the best way to avoid both hype and cynicism.

AI Help: Muse AI

Muse AI is Meta's personal AI assistant, designed to explain complicated topics in simple words. For this article's topic, it can explain proposer-builder separation or the gas limit using an everyday analogy, so the upgrade makes sense even without a technical background.

Join Muse with invite code LTGSWD — in the Muse app, go to Settings > Redeem token and enter the code.

Disclosure: LTGSWD is the author's Muse invite code.

Muse AI is not a trading tool and does not give financial advice.