Layla Zulfa
Longyearbyen, Svalbard – Over 100 dedicated Ethereum core contributors converged recently above the Arctic Circle in Longyearbyen, Svalbard, for the Soldøgn Interop, a week-long intensive workshop focused on hardening the upcoming Glamsterdam network upgrade. This pivotal gathering culminated in significant breakthroughs, including the establishment of a 200 million gas limit floor for the post-Glamsterdam era, the successful implementation of stable ePBS (Proposer-Builder Separation) with external builders, and the finalization of repricing numbers for EIP-8037. The Soldøgn Interop, meaning "midnight sun" in Norwegian, aptly reflected the relentless, 24/7 work ethic embraced by developers under Svalbard’s perpetual daylight.
A Crucial Milestone in Ethereum’s Scalability Roadmap
The Soldøgn Interop represents a critical stride in Ethereum’s ambitious journey toward enhanced scalability and efficiency, a key pillar of its long-term roadmap often referred to as "The Surge." Following the successful Merge, which transitioned Ethereum to Proof-of-Stake, the focus has increasingly shifted to improving transaction throughput and reducing costs for users. The Glamsterdam upgrade, a significant step in this direction, aims to introduce a suite of improvements designed to make the network more robust and capable of handling a larger volume of transactions.
This year’s interop returned to a highly focused, single-track format, reminiscent of previous successful gatherings like Amphora, Edelweiss, and Nyota, which prioritized multi-client progress on specific network upgrades. Unlike last year’s broader Berlinterop, Soldøgn’s singular focus on Glamsterdam allowed for concentrated effort and rapid iteration, compressing weeks of asynchronous development into days of collaborative problem-solving. The attendees comprised a diverse group of client teams, researchers, and protocol developers, representing the decentralized spirit of the Ethereum ecosystem.
Svalbard: A Strategic and Symbolic Setting for Innovation
The choice of Longyearbyen, Svalbard, a remote Norwegian archipelago, was both practical and symbolic. Svalbard is uniquely accessible to individuals of any nationality without a visa, fostering an inclusive environment for a global development community. Beyond its open-border policy, Svalbard is renowned as the home of the Global Seed Vault and the Arctic World Archive—cold-storage facilities tunneled into the permafrost, safeguarding humanity’s critical data, including a snapshot of Ethereum’s source code, for future generations. This deep-storage analogy resonated deeply with the developers working on the foundational code of a decentralized, resilient global computer.
The continuous daylight of the Arctic summer, where the sun does not set from late April through August, provided a metaphorical and literal backdrop for the intensive work. Developers seized this "24/7 uptime" to mirror Ethereum’s own round-the-clock operation, fostering an environment of uninterrupted collaboration and dedication. The isolation and unique environment also minimized distractions, allowing for unparalleled focus on the complex technical challenges at hand.
Glamsterdam Hardening: Unlocking a Higher Gas Limit
The overarching goal of the Soldøgn Interop was to "harden" Glamsterdam implementations and establish a credible target for a post-upgrade gas limit floor. Raising the gas limit safely is a multifaceted engineering challenge, requiring careful consideration of how blocks are constructed and proposed, client implementation overhead under load, and the scaling of state-creation costs. Ethereum’s current gas limit stands at approximately 30 million, a figure that, while substantial, can lead to congestion and high transaction fees during periods of peak demand. The proposed increase to a 200 million gas limit floor represents a monumental 566% increase, promising vastly improved network capacity.
By Friday, the interop successfully established a stable multi-client Glamsterdam devnet, running the latest ePBS, repricing, and block access list specifications. This robust testing environment, coupled with comprehensive benchmarking data, provided the necessary foundation to confidently propose the new, significantly higher gas limit. The week was characterized by intense coding sessions, often extending into the early hours, interspersed with crucial breakout sessions to align on design decisions and chart longer-term roadmap items.
Three dedicated Ethereum Foundation (EF) teams played a crucial role in providing the necessary infrastructure: EthPandaOps deployed ethIQ and a panda MCP server to streamline agentic workflows; Protocol Support established soldogn.xyz as the single source of truth for interop goals, schedules, and notes; and the EF Digital Studio team documented the entire event, with an interop documentary anticipated in the near future.
Core Technical Achievements: The Pillars of Glamsterdam
The successful hardening of Glamsterdam hinged on significant progress across three core technical areas:
1. Enhanced Proposer-Builder Separation (ePBS)
ePBS is a fundamental restructuring of how blocks are constructed and proposed on Ethereum. It introduces explicit deadlines for block construction, payload revelation, and attestations, thereby clarifying and optimizing the proposer/builder relationship. This restructuring is crucial for increasing the headroom available for execution, a prerequisite for safely raising the gas limit.
The week began with the ambitious goal of establishing a 4 Execution Layer (EL) x 4 Consensus Layer (CL) Glamsterdam devnet. Initial attempts revealed several issues, pushing the target to Tuesday, when a 4×3 configuration achieved sufficient stability for stress testing to commence. The remainder of the week was dedicated to an ePBS hardening cycle: stress testing, identifying edge cases, fixing bugs, and repeating the process. A key breakout session on the Builder API substantially simplified specifications related to validator registration, bid/header/commitments flow, builder payment trust models, and circuit-breaker behavior. Mid-week debugging efforts pinpointed cross-client edge cases, particularly concerning execution-request invalidation of beacon requests, which a new test suite revealed to be a universal gap across all client implementations. By Thursday, CL teams reported stable ePBS, with EL-side bid pathways resolving by Friday.
While major progress was made, two contentious questions remain for the All Core Devs (ACD) group: whether a request signature should commit to the receiving builder, and how to maintain resilience against P2P Sybil-based liveness attacks in a 1 ETH-staked-builder design. Despite these open points, by Friday, nearly all clients were successfully running together on glamsterdam-devnet-2 with the external builders pipeline tested end-to-end.
2. Block-Level Access Lists (BAL) Optimizations
While ePBS addresses the consensus layer’s scaling aspects, the execution layer’s counterpart is primarily driven by gas repricings and Block-Level Access Lists (BALs, as per EIP-7928). BALs provide clients with upfront information about a block’s read/write set, enabling crucial optimizations such as parallel execution, batched I/O, and parallel state-root computation. These optimizations are instrumental in determining the maximum block size clients can efficiently process.
The Soldøgn BAL track operated on dedicated devnets, separate from the ePBS chains, to prevent entanglement of optimization benchmarks with consensus-layer stabilization. Each optimization was placed behind its own feature flag, allowing for isolated measurement and comparison. The BAL benchmark dashboard and leaderboard were vital tools, highlighting each client’s worst-case scenarios across the test suite. By focusing on improving the slowest paths first, teams could raise the gas limit floor across the board, rather than merely optimizing for the fastest implementations.
3. Strategic Gas Repricings (EIP-8037)
Glamsterdam incorporates several EL gas repricings designed to better align gas costs with actual resource usage at higher throughputs. Central to this is EIP-8037, which increases the gas cost associated with creating new state. This measure is crucial to ensure that a higher gas limit does not lead to unbounded state growth, which could negatively impact network health and decentralization over time.
Initially, EIP-8037 specified dynamic per-state-byte pricing tied to the block gas limit, which proved challenging for testing and benchmarking due to its combinatorial complexity. Early in the week, teams reached a consensus to eliminate dynamic pricing in favor of a fixed cost_per_state_byte, with future repricings to be handled at subsequent hard fork boundaries.
The accounting model for state gas costs evolved iteratively throughout the week. A Monday breakout shifted state-gas accounting from mid-execution to end-of-call-frame. A Tuesday follow-up addressed account creation costs, code deposit costs, and CREATE-transaction reverts. Wednesday saw the emergence of reservoir refund/refill edge cases, prompting a complete rethinking. By Thursday, accounting reverted to the opcode level, as it was determined that the primary complexity lay within the reservoir model itself. By Friday, the specification had stabilized on bal-devnet-6, with the BAL track successfully delivering the final repricing numbers. This iterative process underscored the value of in-person interops for rapidly resolving complex specification, implementation, testing, debugging, and design challenges, effectively compressing months of asynchronous work into days.
Ultimately, these three threads converged to establish the headline achievement of the week: a credible 200 million post-Glamsterdam gas limit floor. This significant increase is made possible by ePBS structuring slots to provide more execution time, BAL optimizations granting clients the necessary throughput headroom, and EIP-8037 ensuring that a higher gas limit does not result in unsustainable state growth.
Beyond Glamsterdam: Shaping Ethereum’s Future
While Glamsterdam was the primary focus, several breakout sessions looked ahead to Hegotά and subsequent network upgrades, outlining the future trajectory of Ethereum’s development.
Discussions on native Account Abstraction were deliberately proposal-agnostic, focusing instead on defining the core requirements and constraints for any future design. Key feature-set goals included alternative signature schemes, aggregation, batching, recovery, gas sponsorship, and flexible nonces, alongside stringent constraints related to public-mempool compatibility, statelessness, and Layer 2 (L2) Denial-of-Service (DoS) resistance.
A Thursday FOCIL (Frame-Optimized Commitments for Inclusions) breakout provided implementation updates, revealing that early prototypes were already functional. The immediate next steps involve multi-client interop and the establishment of a dedicated FOCIL devnet. Two crucial design decisions emerged: disabling FOCIL during 2-epoch non-finality (mirroring proposer-boost circuit-breaker behavior) and adopting an index-based bookmark approach to ensure compatibility with frame transactions and EIP-7702.
Looking further ahead, a long-running ETH P2P track explored a QUIC-based replacement for libp2p, emphasizing privacy-by-default and slot-aware integration. A prototype for erasure-coded broadcast demonstrated a remarkable six-fold faster propagation than GossipSub for 2.4 MB payloads. The CL track also expressed strong sentiment toward eventually deprecating validator consolidations entirely, proposing a final fork that supports them, followed by a future requirement for exit-then-redeposit, as a cleaner, long-term solution to managing validator-set state growth.
Refining the All Core Devs (ACD) Process
A dedicated session on Wednesday afternoon, led by ACDE co-leads Nixo and Ansgar, gathered valuable input on improving the All Core Devs (ACD) process. The discussion revisited the "headliner construct," debated the merits of a "strawmap" for future forks, and formalized the EIP SFI (Specification, Feasibility, Impact) criteria. There was broad consensus to retain headliners but to introduce more flexibility regarding the rigidity of "EIP-vs-theme," accepting "theme + candidate EIP" as a viable pattern. The per-fork year assignments in the straw map past 2026 were flagged as overly canonicalized and likely to be softened.
A new four-point SFI definition was proposed, with ACDT (All Core Devs Testing) signaling readiness and ACDE (All Core Devs Execution) and ACDC (All Core Devs Consensus) retaining the final say. A new prioritization-ordering process, to be produced after CFI (Call For Inclusion) decisions and reflected in the meta-EIP, will replace SFI’s traditional role in driving devnet inclusion, commencing with Hegotά.
Leadership changes within the ACD call coordination were also announced. Alex Stokes will embark on a three-month sabbatical, with Pari stepping in to moderate ACDC in the interim, and Barnabas filling in for ACDT. The current leadership structure sees Nixo and Ansgar chairing ACDE, Pari as interim ACDC moderator, and Mario, Barnabas, and Danceratopz rotating ACDT moderation.
Operational Excellence and Collaborative Infrastructure
Beyond the headline achievements, the in-person format of Soldøgn facilitated progress on numerous other critical fronts. Teams advanced work on improving test harnesses, significantly compressing Hive feedback loops from hours to minutes. Improvements to engine-API plumbing included gossip deduplication, batched calls, and light-client-driven head discovery. Hard tradeoffs concerning client diversity were also thoroughly discussed, alongside many other topics. The comprehensive session notes from the week are publicly available at soldogn.xyz, providing a detailed record of the intense collaborative effort.
Implications for the Ethereum Ecosystem
The successful Soldøgn Interop carries profound implications for the entire Ethereum ecosystem. For users, the eventual implementation of Glamsterdam with a 200 million gas limit floor promises a substantial increase in network capacity, potentially leading to lower transaction fees and faster confirmation times. This enhanced throughput is crucial for supporting the growing number of decentralized applications (dApps) and users on the network.
For developers, the hardening of ePBS, BALs, and EIP-8037 provides a more stable and predictable environment for building and deploying smart contracts. The clarity on gas repricing and state management enables more efficient resource allocation and cost planning. The progress on future features like Account Abstraction and FOCIL signals a clear path towards a more user-friendly and feature-rich Ethereum, addressing long-standing pain points. The refined ACD process also offers greater transparency and efficiency in protocol development, fostering continued innovation.
Next Steps and Outlook
With the Soldøgn Interop concluded, core development teams will now transition from prototyping to production-readiness. The coming weeks will involve intense, heads-down work on hardening client implementations against the newly finalized specifications, ensuring comprehensive test coverage, and merging the draft Pull Requests generated during the interop into the main codebases.
Final decisions regarding crucial values like the 200 million gas limit target and the definitive repricing numbers will be publicly deliberated and announced during upcoming AllCoreDevs calls, which are expected to focus heavily on these outcomes. The Soldøgn Interop stands as a testament to the Ethereum community’s unwavering commitment to continuous improvement, scalability, and decentralization, marking a significant step forward in building a more robust and accessible global computing platform.
The Ethereum Foundation extends its profound gratitude to all contributors who journeyed to 78°N and dedicated their expertise to making the Soldøgn Interop an unequivocal success. Special commendation is due to EthPandaOps for their organizational prowess and to every individual who toiled under the midnight sun, including the Ethrex crew, participating in their first interop. The week’s achievements were a testament to collaborative spirit and technical excellence, captured for posterity in an anticipated short film.
