What is Ethereum’s Glamsterdam Upgrade?

Ethereum’s next major protocol upgrade, Glamsterdam, aims to increase Layer-1 capacity and improve how blocks are built, propagated and processed. Mainnet deployment is expected in Q4 2026, with Sepolia testing scheduled for October 6. The upgrade focuses on improving transaction processing and network scalability. It also introduces infrastructure designed to support greater parallel execution. 

Why is it Called Glamsterdam?

Ethereum upgrades combine names from the execution and consensus layers. ‘Glamsterdam’ combines Amsterdam, the execution-layer upgrade named after a previous Devcon location, with Gloas, the consensus-layer upgrade named after a star.

The upgrade follows Fusaka, activated in December 2025, and focuses on Ethereum’s ‘Scale L1' and ‘Scale Blobs’ objectives. Ethereum’s roadmap says Glamsterdam is intended to improve parallelization, expand capacity and control long-term database growth.

Enshrined Proposer-Builder Separation

A headline change is EIP-7732, or Enshrined Proposer-Builder Separation. Ethereum currently relies partly on external infrastructure to coordinate block proposers and builders.

Glamsterdam would move this separation into the protocol itself. According to Ethereum.org, ePBS could expand the effective execution-payload propagation window from roughly two seconds to nine seconds. More propagation time could allow larger amounts of data to move safely through the network while reducing dependence on third-party middleware. 

Block-Level Access Lists

EIP-7928 introduces Block-Level Access Lists, or BALs. These map which parts of Ethereum’s state transactions access and modify.

Mapping these dependencies in advance can support parallel disk reads, faster synchronization and eventually greater parallel transaction processing. The Ethereum Foundation’s 2026 protocol priorities say BALs support efforts to raise Ethereum’s gas limit toward and beyond 100 million.

Lower Costs and Larger Contracts

Glamsterdam also includes EIP-2780, which restructures intrinsic transaction gas. Ethereum.org says ordinary ETH transfers between existing accounts could become up to 71% cheaper. Transfers creating new accounts would still carry an additional charge to reflect long-term state-storage costs.

Developers also gain additional capacity. EIP-7954 raises Ethereum’s maximum contract size from roughly 24 KiB to 64 KiB, allowing larger applications. 

Testing is Already Underway

The Ethereum Foundation launched the Platåberget testnet in August as a public testing environment for Glamsterdam. Developers were warned that tools assuming a fixed 21,000-gas transfer cost or a single gas dimension may require updates. 

Ethereum’s September protocol update says Glamsterdam is approaching mainnet while developers have already moved into planning its successor, Hegotá. Ethereum’s current roadmap lists Glamsterdam for Q4 2026, with no confirmed mainnet date, while Hegotá is currently expected in Q2 2027. 

Existing ETH holders do not need to convert their tokens. Ethereum warns that anyone requesting an 'ETH upgrade' is attempting a scam.

Final Thoughts

Glamsterdam is a structural scaling upgrade rather than a user-facing redesign. By combining ePBS, BALs, revised gas pricing and larger contracts, Ethereum is preparing its base layer for higher throughput while trying to keep validation sustainable and decentralized.

Also Read: How Ethereum Scales Without Sacrificing Decentralization

FAQs:

1. What is Ethereum’s Glamsterdam upgrade?

Glamsterdam is Ethereum’s next major protocol upgrade, expected in Q4 2026. It focuses on increasing Layer-1 capacity, improving block propagation and preparing Ethereum for more efficient parallel transaction processing.

2. What is ePBS in the Glamsterdam upgrade?

EIP-7732 introduces Enshrined Proposer-Builder Separation, bringing the separation of block proposers and builders directly into Ethereum’s protocol. It could increase the effective execution-payload propagation window from roughly two to nine seconds.

3. What are Block-Level Access Lists in Ethereum?

EIP-7928 introduces BALs that describe which parts of Ethereum’s state transactions access and modify. This information can support parallel disk reads, faster synchronization and infrastructure for greater parallel execution.

4. Will Glamsterdam reduce Ethereum gas fees?

EIP-2780 restructures intrinsic transaction gas, and Ethereum.org says ordinary ETH transfers between existing accounts could become up to 71% cheaper. Actual transaction costs will still depend on network conditions and transaction type.

5. Do ETH holders need to upgrade their tokens for Glamsterdam?

No. Existing ETH remains valid automatically when the network upgrades, and holders do not need to exchange or convert their tokens. Ethereum warns that requests to 'upgrade' ETH tokens are scams.