Ethereum has just activated Glamsterdam on the Sepolia testnet. The crypto upgrade was launched on October 6 at 1:53 p.m. UTC, at epoch 353 024. Several important changes are now being tested on a public network: new organization of block construction, preparation of parallel processing and revision of certain gas costs. The mainnet will still have to wait.
In brief
- Glamsterdam is now active on the Sepolia testnet.
- The upgrade notably tests ePBS and Block-Level Access Lists.
- Hoodi then the mainnet constitute the next stages of deployment.
Glamsterdam finally passes to Sepolia
Ethereum had set October 6 as the date for the Glamsterdam public test. Activation took place at slot 11 296 768, i.e. at 1:53:36 p.m. UTC. Sepolia represents a very different step from the private networks used during development.
The testnet brings together more operators, software and different configurations. This allows teams to verify that execution and consensus clients are all correctly applying the new rules.
Node operators had to install compatible versions before the fork. This particularly concerns software like Geth, Besu and Reth for execution, as well as Prysm, Teku or Lodestar for consensus.
ETH holders do not need to do anything. Sepolia ethers are only test tokens and Glamsterdam is not yet active on the Ethereum mainnet.
However, the passage to Sepolia was not guaranteed a few weeks earlier.
The devnets had encountered several finality problems and a bug linked to the new gas pricing. Ethereum still had to correct several issues before exposing Glamsterdam to a public network. This phase is now behind him. The work is now changing terrain.
ePBS changes Ethereum block construction
Glamsterdam contains a particularly important modification: ePBS, for enshrined propose-builder separation. Ethereum already uses a separation between the validator who proposes a block and the specialized actors who construct its content.
Builders seek in particular to organize transactions efficiently before offering their blocks to validators. Part of this architecture today depends on software and infrastructure located outside of the protocol itself.
EIP-7732 wants to integrate this organization directly into the rules of Ethereum. The builder prepares the block. The proposer publishes the corresponding commitment. The protocol then organizes the revelation of the content, its validation and payment.
The change may seem very technical, but it directly affects the way Ethereum produces its blocks. One goal is to give validators more time to verify execution. With heavier blocks, each available millisecond becomes more important.
ePBS must also reduce Ethereum’s dependence on certain external infrastructures used today to coordinate constructors and validators.
The construction of blocks thus becomes more native to the network. This project is particularly important in Ethereum’s crypto strategy: the protocol wants to significantly increase its capacity without asking validators to simply process more data in the same period of time. Glamsterdam therefore begins by reorganizing the mechanics before increasing the load.
Block-Level Access Lists prepare for parallel processing
The other big new thing concerns Block-Level Access Lists, or BALs. When an Ethereum block contains many transactions, they interact with different accounts, smart contracts and storage locations.
Today, clients must discover some of these accesses at runtime. EIP-7928 adds a list that indicates the state elements used by a block and certain modifications that are made to them.
This information opens the door to more parallel work. If no two operations use the same data, clients can prepare or process part of their execution simultaneously rather than systematically waiting for each previous operation to complete.
Ethereum does not instantly become a fully parallel blockchain.
Above all, the BALs provide one of the necessary building blocks to move in this direction. They can also facilitate data reads from disk and certain calculations performed after execution. The desired gain directly concerns the time necessary to process a block.
The more transactions Ethereum wants to accept, the more important this question becomes. Simply increasing the size of blocks without speeding up their processing could make nodes more expensive to operate and complicate validation.
This is where Glamsterdam joins the network’s larger purpose. Developers now consider that a capacity of 200 million gas after Glamsterdam becomes technically feasible. Ethereum is currently around 60 million. The change in scale would be considerable.
The cost of gas must also change
More capacity creates another problem: not all Ethereum operations cost the network the same. A transaction can require computation for a few moments without leaving much data behind. Another can create new information that the nodes will have to keep permanently.
However, historical gas pricing does not always perfectly reflect this difference. Glamsterdam needs to correct some of this imbalance. In particular, EIP-8037 introduces a more precise way of measuring the cost associated with the creation of a new state.
The objective is to prevent the increase in flow explodes the size of data that each node must maintain. EIP-8038 also reviews the cost of several state access operations. Consequence: certain operations may cost more gas after the upgrade.
It’s voluntary. Ethereum isn’t just looking to lower fees on every transaction. Above all, he wants each operation to pay an amount closer to the resources it actually consumes. Some applications therefore need to check their code. Tools that use hardcoded gas limits may experience issues. Fee estimators, wallets and development infrastructures were also invited to test the new rules before moving to the mainnet.
A simple transfer to an existing account will not necessarily be affected in the same way as an operation creating new permanent data. Scaling therefore also involves prices. More space, but not free for all operations.
Hoodi must now pave the way to the mainnet
Sepolia is not the final destination. Ethereum still needs to upgrade Glamsterdam to Hoodi, its other large test environment used in particular by validators and staking infrastructures.
No definitive date has yet been announced. The mainnet doesn’t have any more. The developers first want to observe how Sepolia reacts to the new rules: purpose, compatibility between clients, ePBS behavior, block creation, operation of BALs and new gas rules.
A significant problem could further push back the schedule. The stakes are high. Ethereum secures hundreds of billions of dollars in assets, stablecoins, DeFi protocols and tokenized products. An error that goes unnoticed on a testnet can become much more costly when it hits the mainnet.
The tests serve precisely to avoid it. After Glamsterdam, Ethereum is already working on Hegotá, the next big upgrade planned for 2027. Several proposals are still being studied, particularly around privacy and censorship resistance.
But the immediate construction site remains Glamsterdam. Sepolia is now active. Hoodi must follow. Only then will the main network come. If everything works correctly, Ethereum will have a much more solid technical basis to push its layer 1 beyond the current limits.
The 200 million gas will not be automatically activated with Glamsterdam. Validators will have to gradually raise their parameters and the network will have to show that it can absorb the load. This is precisely what the next tests should make it possible to measure. Glamsterdam is therefore not yet accelerating Ethereum for all its users. But the first major public test of this new architecture has now been launched.
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