Ethereum’s Glamsterdam upgrade launches on Sepolia testnet

Ethereum’s Glamsterdam upgrade has gone live on the Sepolia testnet, in one of the final major rehearsals before its mainnet activation.

Glamsterdam went live on Sepolia on Tuesday at 1:53 pm UTC, Ethereum community contributor Pooja Ranjan announced in an X post. 

The upgrade aims to advance Ethereum’s layer-1 scaling roadmap with enshrined proposer-builder separation, block-level access lists and changes to gas pricing that better reflect the cost of execution, the Ethereum Foundation announced in a Sept. 28 blog post.

The development marks one of the final testnet launches for Glamsterdam, arguably one of the most consequential upgrades of 2026, aiming to make the Ethereum network more scalable and efficient. 

Following the testnet launch, developers will determine Glamsterdam’s activation date on the Hoodi testnet, before determining the final date of its mainnet launch.

Glamsterdam activation schedule. Source: Ethereum.org

Aiming to improve Ethereum’s efficiency and scalability

Glamsterdam marks the next major upgrade after Fusaka, designed to improve scalability, harden the layer-1 and make the network easier to use.

The upgrade’s headliner changes are enshrined proposer-builder separation (ePBS) and block-level access lists (BALs), which change how blocks are produced and validated to support greater throughput on the Ethereum mainnet.