Glamsterdam Testnet Announcement

What happened

Glamsterdam follows the Fusaka upgrade, advancing Ethereum's L1 scaling roadmap with enshrined proposer-builder separation, block-level access lists, and changes to gas pricing that better reflect the cost of execution and state growth. The Glamsterdam network upgrade is scheduled to activate on Sepolia at epoch 353,024 , slot 11,296,768 (October 6, 2026, 13:53:36 UTC) .

Glamsterdam Overview Glamsterdam combines the Amsterdam execution layer upgrade with the Gloas consensus layer upgrade. Hoodi and mainnet activation dates have not yet been decided.

Node operators must update both their execution and consensus layer clients before activation. Its headlining changes are enshrined proposer-builder separation (ePBS) and block-level access lists (BALs), which change how blocks are produced and validated to support greater L1 throughput (how much work a system gets through in a given time).

Enshrined Proposer-Builder Separation EIP-7732 brings the separation between block proposers and builders into Ethereum's consensus protocol. A proposer contains a builder's commitment to an execution payload, and the builder subsequently reveals that payload. The protocol handles payment to the proposer, reducing reliance on trusted middleware for the exchange between proposers and builders.

Key facts

• A proposer — includes: a builder's commitment to an execution payload, and the builder subsequently reveals that payload