Soldøgn Interop Recap ☀️

Soldøgn Interop Recap: A Week of Intense Progress Above the Arctic Circle

As the sun shines brightly above the Arctic Circle, a group of over 100 Ethereum core contributors gathered in Longyearbyen, Svalbard, for the Soldøgn Interop. This week-long event brought together the best minds in the Ethereum community to work on a critical upgrade to the Glamsterdam network. The Soldøgn Interop was a resounding success, with teams delivering on their core goals and making significant progress on various fronts.

Why Svalbard?

Svalbard, a Norwegian archipelago in the Arctic Circle, was chosen as the venue for the Soldøgn Interop due to its unique characteristics. The region is one of the few places on Earth where anyone, regardless of nationality, can live and work without a visa. Additionally, Svalbard is home to the Global Seed Vault and the Arctic World Archive, two cold-storage facilities that hold backups of crops, books, films, manuscripts, and source code that humanity might need a thousand years from now, including a snapshot of Ethereum's source code. The 24/7 uptime in Svalbard, where the sun doesn't set from late April to August, made it an ideal location for a week-long event that required continuous work.

Harden Glamsterdam, Scale Ethereum

The primary goal of the Soldøgn Interop was to harden Glamsterdam implementations and derive a target for a post-upgrade gas limit floor. Glamsterdam is a network upgrade that tackles several challenges, including how blocks are built and proposed, how much headroom client implementations have under load, and how state-creation costs scale alongside throughput. By raising the gas limit safely, Ethereum can increase its scalability and efficiency.

ePBS: Restructuring Slots for Increased Headroom

One of the key components of Glamsterdam is the ePBS (Efficient Proposer Builder System), which restructures slots to give execution more time. This allows for increased headroom, making it possible to raise the gas limit safely. Teams worked on stress testing and exposing edge cases, with a Tuesday-morning Builder API breakout substantially simplifying the spec around validator registration, bid/header/commitments flow, trust model for builder payments, and circuit-breaker behavior.

BAL Optimizations: Enabling Parallel Execution and Batched I/O

The execution layer counterpart to ePBS has two dominant pieces: gas repricings and Block-Level Access Lists (BALs). BALs enable parallel execution, batched I/O, and parallel state-root computation, all of which determine how big a block clients can comfortably handle. The Soldøgn BAL track ran on its own devnets, separate from the Glamsterdam ePBS chains, with each optimization sitting behind its own feature flag.

Gas Repricings: Calibrating Costs to Better Match Resource Usage

Glamsterdam includes a number of EL gas repricings, calibrating costs to better match resource usage at higher throughput. EIP-8037, the state-creation gas cost increase, sits at the core, raising the price of writing new state so that a higher gas limit doesn't translate into unbounded state growth. Teams agreed to drop dynamic pricing in favor of a fixed cost_per_state_byte, with future repricing handled at fork boundaries rather than within a fork.

Other Glamsterdam Threads

Beyond ePBS, BALs, and repricings, most of the remaining Glamsterdam scope was hashed out across breakout sessions. CL teams finalized decisions on smaller Glamsterdam EIPs, including EIP-8061 (exit/consolidation churn increase), EIP-8080 (exits via the consolidation queue), and EIP-8045 (slashed-validator duty removal). A Wednesday-morning EL/CL sync architecture breakout deferred EIP-8237 out of Glamsterdam in favor of preserving optionality for a longer-term "top-up sync" architecture in a future fork.

Hardening and Testing

Hardening was a constant theme of the week, with a Thursday session covering fork-choice compliance testing frameworks, the Diamond repo of reproducible CL edge-case scenarios, and buildoor, PandaOps' external-builder testing tool. Teams used the in-person time to make progress on everything from better test harnesses to engine-API plumbing improvements.

Next Steps

From here, teams head home to take what was prototyped during the week and make it production-ready. Expect the next several weeks to be heads-down on hardening client implementations against the new specs, finalizing test coverage, and turning Soldøgn's draft PRs into merged code. The final decisions for values such as the 200M gas limit target and final repricing numbers will be made and shared publicly on AllCoreDevs calls.

Conclusion

The Soldøgn Interop was a resounding success, with teams delivering on their core goals and making significant progress on various fronts. The event demonstrated the power of in-person collaboration and the importance of continuous work towards a common goal. As Ethereum continues to evolve and grow, events like the Soldøgn Interop will play a crucial role in shaping the future of the network.

Source: https://blog.ethereum.org/en/2026/05/02/soldogn-interop-recap