Ethereum’s next major network upgrade, Glamsterdam, has entered a new stage of public testing as developers prepare for changes designed to increase network capacity, improve transaction processing and alter how parts of Ethereum’s infrastructure handle blocks and data.
The upgrade has not yet launched on Ethereum mainnet. Ethereum’s official roadmap currently lists Glamsterdam as a Q4 2026 mainnet upgrade, while the Sepolia testnet fork is scheduled for October 6. A final mainnet date has not been confirmed.
For developers, the testing period is particularly important because some of the planned changes can affect wallets, infrastructure, gas estimators and smart contracts.
What is the Glamsterdam upgrade?
Glamsterdam combines the names of the planned execution-layer upgrade, Amsterdam, and the consensus-layer upgrade, Gloas.
It follows Ethereum’s Fusaka upgrade, which went live in December 2025 and introduced PeerDAS, increased data capacity for Layer 2 networks and made other changes to the network’s execution and consensus layers.
Glamsterdam takes the next step by focusing heavily on Ethereum’s Layer 1 capacity.
Ethereum says the upgrade is designed around three broad goals:
- Faster transaction processing through preparation for parallel execution
- Greater network capacity
- More sustainable management of Ethereum’s growing state and database
The aim is to allow Ethereum to process more activity without requiring increasingly demanding hardware from ordinary node operators.
Developers are already testing the changes
The Ethereum Foundation announced the Platåberget testnet in August as an early public testing environment for Glamsterdam.
The Foundation warned that the upgrade introduces breaking changes for some application developers.
In particular, software that relies on a hard-coded maximum gas limit, including some wallets, indexers and gas-estimation tools, may need to be updated.
That makes the testing period more than a technical exercise for Ethereum’s core developers.
Teams building applications around Ethereum also need to test their infrastructure against the new network behaviour.
The Platåberget testnet is intended to give developers time to identify and fix problems before Glamsterdam reaches longer-lived public testnets and eventually mainnet.
What changes are coming for Ethereum’s infrastructure?
One of the most significant planned changes is enshrined proposer-builder separation, commonly abbreviated as ePBS.
Under the current system, block proposers and builders interact through infrastructure that exists partly outside Ethereum’s core protocol.
Glamsterdam is designed to bring this relationship into the protocol itself.
Ethereum says ePBS can reduce reliance on third-party relays while allowing larger amounts of data to move through the network’s block-production process.
The change is aimed primarily at Ethereum’s underlying architecture rather than being a new application that ordinary users download.
Its importance is therefore likely to be felt through network performance and infrastructure over time rather than through a completely new interface for everyday users.
Block-level access lists are another major change
Glamsterdam also includes block-level access lists, or BALs.
These are intended to make it easier for Ethereum to understand which parts of its state are being accessed during block processing.
That information can help the network prepare for more parallel processing.
Instead of forcing every transaction to be processed strictly one after another, Ethereum’s architecture can increasingly identify operations that do not depend on one another and prepare them for more efficient processing.
The broader objective is to increase capacity without sacrificing the decentralised nature of the network.
Some transaction costs could change
The upgrade also includes changes to the way Ethereum prices certain operations.
One proposal, known as Reduce Intrinsic Transaction Gas, is designed to lower the basic gas cost associated with simple ETH transfers.
Ethereum’s official Glamsterdam documentation says the change could make a standard ETH transfer significantly cheaper by separating the basic computational work required for a transaction from more complex operations.
However, users should not interpret the proposal as a guarantee that every Ethereum transaction will suddenly become cheaper.
Gas prices depend on network demand and the type of transaction being executed.
Changes to the protocol can alter the underlying cost structure, but the actual amount a user pays can still vary.
Smart-contract developers need to pay attention
Ethereum developers have also warned that Glamsterdam’s gas repricing changes could affect a small number of existing smart contracts.
In an August 24 update, the Ethereum Foundation said EIP-8037 and EIP-8038 would adjust the cost of creating and accessing state so that gas prices more closely reflect the underlying resource requirements.
The Foundation said historical transaction testing identified a small group of contracts that rely on assumptions affected by the new pricing schedule.
Most of the identified problems can reportedly be addressed by increasing gas limits, and the Foundation said the large majority of smart contracts are unaffected.
The affected developers are being encouraged to test their applications before the changes reach mainnet.
What does Glamsterdam mean for ordinary ETH users?
For someone who simply holds ETH or sends occasional transactions, there may be little to do immediately.
The upgrade is primarily a protocol-level change.
Users are not expected to manually change the Ethereum network in their wallets when the upgrade eventually reaches mainnet, although wallet and infrastructure providers need to support the new protocol version.
Ethereum’s own guidance says regular users do not need to take action in response to the current gas-repricing testing. Updated wallets and infrastructure are expected to handle the changes.
The more visible benefits for users could emerge indirectly.
If Ethereum can process more activity efficiently, network capacity can improve.
If certain transaction costs decline, some everyday transactions may become cheaper.
If Layer 2 networks can use Ethereum’s underlying infrastructure more efficiently, users could also benefit through applications built on those networks.
Those are intended outcomes, however, rather than guarantees about future transaction prices.
Layer 2 networks remain part of the strategy
Ethereum’s development roadmap increasingly focuses on the relationship between Ethereum’s main network and Layer 2 networks.
Fusaka’s PeerDAS upgrade was designed to increase the amount of data Ethereum can make available to rollups while reducing the amount of data individual validators need to download.
Glamsterdam continues this scaling strategy.
Ethereum’s official documentation says ePBS could extend the time available for propagating block data, helping the network accommodate larger payloads and more data blobs for Layer 2 networks.
That matters because many Ethereum applications now rely on Layer 2 networks to handle transactions at lower costs while using Ethereum as an underlying settlement and security layer.
Ethereum’s development is moving toward more frequent upgrades
Glamsterdam is part of a broader shift in Ethereum’s development process.
The network has moved through several major upgrades in recent years:
- The Merge in 2022
- Shapella in 2023
- Dencun in 2024
- Pectra in 2025
- Fusaka in 2025
Ethereum’s current roadmap lists Glamsterdam for Q4 2026 and Hegotá for 2027.
This approach means Ethereum is being changed through a continuing series of technical improvements rather than waiting for one massive future redesign.
The Ethereum Foundation has also published a set of longer-term protocol priorities covering work through 2029, including scaling, state management, user experience and decentralisation.
The upgrade is still subject to testing
One important point for users and developers is that the current Glamsterdam specification is not the same thing as a completed mainnet deployment.
Ethereum’s official roadmap says the upgrade is still being tested and that the scope can change before mainnet activation.
That means developers should not treat every current testnet behaviour as the final Ethereum mainnet implementation.
The October 6 Sepolia fork is another important milestone because it will provide a longer-lived public environment for testing the upgrade.
What developers should watch next
Ethereum developers and infrastructure operators will be watching several milestones.
These include:
- Continued testing on Platåberget
- The Sepolia fork
- Client updates supporting Glamsterdam
- Smart-contract compatibility testing
- Gas-repricing results
- Performance of ePBS
- Block-level access-list testing
- The eventual mainnet activation date
Developers running nodes or validators will need to follow official client-release information when the mainnet fork approaches.
Ethereum specifically advises node operators and stakers to use client versions that support the upgrade.
What happens next?
The immediate focus is testing rather than deployment.
The October 6 Sepolia milestone will provide another opportunity for developers and infrastructure teams to test their applications against the planned changes.
If testing proceeds successfully, Ethereum can move closer to a mainnet activation.
But there is currently no confirmed date for that final step.
For users, the main story is therefore not that Ethereum has already received a new upgrade.
It is that the network is actively testing the next set of changes that could affect scalability, transaction costs, smart-contract execution and the infrastructure used by Ethereum applications.
Glamsterdam represents another stage in Ethereum’s attempt to increase capacity while preserving security and decentralisation. Its eventual impact will depend on how the proposed changes perform in testing and how developers, wallets, validators and applications adapt before the upgrade reaches mainnet.
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