Layla Zulfa
In a remarkable week of intensive collaboration, over 100 Ethereum core contributors convened above the Arctic Circle in Longyearbyen, Svalbard, for the Soldøgn Interop. This specialized gathering was dedicated to accelerating the development and hardening of the upcoming "Glamsterdam" network upgrade, a pivotal step in Ethereum’s ongoing evolution towards enhanced scalability and efficiency. The secluded, unique setting fostered a concentrated environment, enabling rapid progress on complex technical challenges.
A Strategic Arctic Summit for Ethereum’s Future
The Soldøgn Interop, held just over a week ago, was a critical assembly in Ethereum’s methodical upgrade roadmap. Following last year’s Berlinterop, Soldøgn reinstated the focused, single-track format pioneered by previous successful interops like Amphora (2021), Edelweiss (2023), and Nyota (2024). This concentrated approach allows multi-client teams to converge on specific upgrade goals, fostering an environment where intricate issues can be resolved in hours rather than weeks of asynchronous communication. For Glamsterdam, the primary objective was to harden its implementations and lay the groundwork for a significant increase in the network’s transaction capacity.
By the close of the week, the concentrated efforts yielded substantial results, fulfilling three core objectives: a consensus on a post-Glamsterdam gas limit floor of 200 million, the successful implementation of stable ePBS (Ethereum Proposer-Builder Separation) running with external builders, and the finalization of repricing numbers for EIP-8037. Beyond these immediate Glamsterdam goals, significant strides were also made on features slated for the subsequent "Hegotå" upgrade, including FOCIL (Fraud-Proof Optimistic Commit-Chain Integration Layer) and native account abstraction, alongside a multitude of other critical topics.
The choice of Svalbard, a Norwegian archipelago known for its stark beauty and unique geopolitical status, was more than just a picturesque backdrop. It offered a visa-free environment for attendees of all nationalities, symbolizing Ethereum’s global and inclusive ethos. Furthermore, Svalbard is home to the Global Seed Vault and the Arctic World Archive, subterranean cold-storage facilities designed to preserve humanity’s most vital data and biological diversity for millennia – including a snapshot of Ethereum’s own source code. This symbolic resonance with long-term preservation and resilience mirrored the core developers’ mission to build a robust and enduring decentralized infrastructure. Adding to the unique atmosphere, the "midnight sun" phenomenon from late April to August meant 24/7 daylight, a fitting metaphor for Ethereum’s uninterrupted uptime, which the core developers leveraged to its fullest extent.
Glamsterdam: Hardening the Network, Scaling Ethereum
The overarching goal for Soldøgn was to strengthen Glamsterdam implementations and establish a credible target for a post-upgrade gas limit floor. Raising Ethereum’s gas limit safely is a multi-faceted challenge, requiring careful consideration of how blocks are constructed and proposed, client implementation performance under load, and the scalability of state-creation costs relative to network throughput. The current gas limit stands at 30 million, meaning a jump to 200 million represents an almost seven-fold increase in potential transaction capacity per block – a transformative leap for the network’s scalability.
Practically, this translated into achieving a stable multi-client Glamsterdam development network running the latest ePBS, repricing, and block access list specifications. Concurrently, extensive benchmarking data was collected to substantiate a robust gas limit proposal. The majority of the week involved intense, heads-down coding sessions, often extending into the early hours, interspersed with crucial breakout discussions to align on design decisions and chart the long-term roadmap.
Essential infrastructure support for the week was provided by three Ethereum Foundation (EF) teams:
- EthPandaOps delivered
ethIQfor performance monitoring and apanda MCP serverto facilitate agentic workflows. - Protocol Support managed
soldogn.xyz, serving as the central hub for interop goals, schedules, and detailed notes. - The EF Digital Studio team meticulously documented the event, promising the release of the very first interop documentary, offering a rare glimpse into the collaborative spirit driving Ethereum’s development.
ePBS: Reshaping the Consensus Layer for Efficiency
A cornerstone of the Glamsterdam upgrade and a major focus at Soldøgn was ePBS, or Ethereum Proposer-Builder Separation. Beyond merely refining the relationship between block proposers and builders, ePBS fundamentally restructures block slots by introducing explicit deadlines for block construction, payload revelation, and attestations. This architectural change clearly delineates the time allocated for execution, thereby increasing the "headroom" available for safely raising the gas limit. The intention is to further decentralize block production, reduce the potential for Maximal Extractable Value (MEV) to centralize power, and enhance overall network resilience.
Teams began the week with the ambitious target of establishing a stable 4 Execution Layer (EL) x 4 Consensus Layer (CL) Glamsterdam devnet by Monday evening. Initial attempts revealed several issues, pushing the target to Tuesday, when a 4×3 configuration achieved sufficient stability to commence stress testing. The rest of the week evolved into an intensive ePBS hardening cycle: continuous stress testing, identification and resolution of edge cases, and iterative fixes.
A critical Builder API breakout session on Tuesday morning significantly simplified the specification surrounding validator registration, the bid/header/commitments flow, the trust model for builder payments, and circuit-breaker behavior. Mid-week debugging efforts pinpointed cross-client edge cases, particularly concerning the invalidation of beacon requests by execution requests. A new test suite revealed a surprising gap across all client implementations, underscoring the value of multi-client interop for uncovering such systemic issues. By Thursday morning, CL teams reported stable ePBS operations, while EL-side bid pathways were debugged and resolved by Friday. Two key questions remain contentious for the All Core Developers (ACD): whether a request signature should commit to the receiving builder, and how to ensure the resilience of a 1 ETH-staked-builder design against P2P Sybil-based liveness attacks. Despite these outstanding points, the week concluded with nearly all clients successfully running together on glamsterdam-devnet-2, with the external builders pipeline thoroughly tested end-to-end.
BAL Optimizations: Supercharging Execution Layer Throughput
While ePBS fortifies the consensus layer, the execution layer’s scaling narrative within Glamsterdam is largely driven by gas repricings and Block-Level Access Lists (BALs), specified in EIP-7928. BALs provide clients with crucial upfront information about a block’s read/write set. This foresight is instrumental in enabling parallel execution, facilitating batched I/O operations, and accelerating parallel state-root computation – all vital elements that dictate how large a block clients can efficiently process. The ability to predict and optimize these operations is a direct enabler of a higher gas limit.
At Soldøgn, the BAL track operated on its own dedicated devnets, independent of the Glamsterdam ePBS chains. This isolation ensured that optimization benchmarks were not complicated by ongoing consensus-layer stabilization work. Each optimization was placed behind its own feature flag, allowing for isolated comparison and measurement. The BAL benchmark dashboard and leaderboard proved invaluable, highlighting each client’s worst-case scenarios across the test suite. By systematically addressing and improving the slowest paths first, teams could raise the gas limit floor across the board, rather than merely optimizing for the fastest implementations.
Gas Repricings: Balancing Scalability with State Growth (EIP-8037)
The Glamsterdam upgrade incorporates several Execution Layer gas repricings, recalibrating transaction costs to more accurately reflect resource consumption at increased throughput levels. At the heart of these repricings is EIP-8037, which proposes an increase in the gas cost of creating new state. This is a critical mechanism designed to prevent a higher gas limit from inadvertently leading to unchecked state growth, which could burden nodes and compromise the network’s long-term health.
Entering Soldøgn, the EIP-8037 specification featured dynamic per-state-byte pricing tied to the block gas limit, which presented significant challenges for combinatorial testing and benchmarking. Recognizing this complexity, teams made an early decision to drop dynamic pricing in favor of a fixed cost_per_state_byte, with any future repricing adjustments to be handled at subsequent hard fork boundaries. This simplification streamlined development significantly.
The accounting model for EIP-8037 underwent an iterative refinement process throughout the week. Monday’s breakout shifted state-gas accounting from mid-execution to the end-of-call-frame. A Tuesday follow-up addressed account creation costs, code deposit costs, and CREATE-transaction reverts. Wednesday’s discussions surfaced complex reservoir refund/refill edge cases, necessitating a re-evaluation. The Thursday breakout ultimately reverted accounting to the opcode level, concluding that the primary complexity resided in the reservoir model itself rather than the accounting computation. By Friday, the specification had stabilized on bal-devnet-6, with the BAL track successfully delivering the final repricing numbers. This rapid iteration and resolution exemplify the core value of interop events, compressing months of asynchronous work into a few intensely productive days.
The convergence of these three critical threads – ePBS providing execution time, BAL optimizations enhancing client throughput, and EIP-8037 managing state growth – culminated in the headline achievement of the week: a credible 200 million post-Glamsterdam gas limit floor. This substantial increase is poised to dramatically enhance Ethereum’s capacity, making it more robust and accessible for a wider array of decentralized applications.
Beyond the Core: Other Glamsterdam and Future Roadmap Threads
While ePBS, BALs, and gas repricings dominated the main tracks, numerous other Glamsterdam scope items were refined and resolved through dedicated breakout sessions.
Consensus Layer (CL) teams finalized decisions on several smaller Glamsterdam EIPs: EIP-8061 (exit/consolidation churn increase) was included in glamsterdam-devnet-1. EIP-8080 (exits via the consolidation queue) was declined for inclusion. EIP-8045 (slashed-validator duty removal) was narrowed in scope to proposer duties within the look-ahead window. EIP-7688 (SSZ stable containers) remains within Glamsterdam’s scope but was held out of glamsterdam-devnet-1 pending further work on bounded gossip-message sizes for attestations under progressive lists.
A Wednesday-morning EL/CL sync architecture breakout deferred EIP-8237 out of Glamsterdam, opting to preserve optionality for a longer-term "top-up sync" architecture in a future fork. In its place, the group agreed to draft a new EIP that standardizes forkchoiceUpdated / newPayload / getPayload sequencing, specifies a snap-sync initiation handshake, and tightens valid/invalid consistency between the engine API surfaces. Hardening was a constant theme throughout the week, with a Thursday session covering fork-choice compliance testing frameworks, the Diamond repository for reproducible CL edge-case scenarios, and buildoor, EthPandaOps’ external-builder testing tool, which was demoed to an enthusiastic audience eager to suggest attack scenarios.
Looking further ahead, several breakouts laid groundwork for "Hegotå" and subsequent upgrades. A proposal-agnostic session on native Account Abstraction explored the requirements and constraints for future designs, aiming for features like alternative signature schemes, aggregation, batching, recovery, gas sponsorship, and flexible nonces, all while adhering to hard constraints around public-mempool compatibility, statelessness, and Layer 2 (L2) DoS resistance.
A Thursday FOCIL (Fraud-Proof Optimistic Commit-Chain Integration Layer) breakout focused on implementation updates, with early prototypes already functional and multi-client interop and a dedicated FOCIL devnet identified as immediate next steps. Key design decisions included disabling FOCIL during 2-epoch non-finality (mirroring proposer-boost circuit-breaker behavior) and adopting an index-based bookmark approach for compatibility with frame transactions / EIP-7702.
On the ETH P2P front, a long-running track sketched out a QUIC-based replacement for libp2p, promising privacy-by-default and slot-aware integration. An erasure-coded broadcast prototype demonstrated a simulated ~6x faster propagation than GossipSub on 2.4 MB payloads. The CL track also expressed a strong sentiment towards eventually deprecating consolidations entirely – declaring a final fork that supports them, then requiring exit-then-redeposit afterwards – as a cleaner long-term solution to validator-set state growth.
Evolving the All Core Developers (ACD) Process
A dedicated session led by Nixo and Ansgar, the two ACDE co-leads, on Wednesday afternoon gathered crucial input from core contributors regarding the ACD process itself. Discussions revisited the "headliner construct," debated the utility of having a "strawmap" (a tentative roadmap), and formalized the EIP SFI (Specification Freeze Index) criteria. There was broad consensus to retain headliners but to loosen the rigidity between EIPs and broader themes, accepting "theme + candidate EIP" as a viable pattern. The per-fork year assignments in the strawmap past 2026 were deemed overly canonicalized and likely to be softened. A new four-point SFI definition was proposed, granting ACDT (All Core Developers – Testing) the role of signaling readiness, with ACDE (Execution) and ACDC (Consensus) retaining the final call. 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 Hegotå.
On the call-coordination front, Alex Stokes announced a three-month sabbatical, with Pari stepping in to cover ACDC moderation and Barnabas filling in for ACDT during this period. The current leadership structure for ACD calls now sees Nixo and Ansgar chairing ACDE, Pari as interim for ACDC, and Mario, Barnabas, and Danceratopz rotating ACDT moderation.
The Power of Collaboration: Everything Else
Beyond the headline items, the in-person environment at Soldøgn facilitated progress on a myriad of other crucial development fronts. Teams enhanced test harnesses, compressing Hive feedback loops from hours to minutes. Improvements were made to engine-API plumbing, including gossip deduplication, batched calls, and light-client-driven head discovery. Hard tradeoffs around client diversity were thoroughly discussed, underscoring the community’s commitment to a robust, decentralized network. A comprehensive list of all session notes is publicly available at soldogn.xyz.
Next Steps and Outlook
As the core developers return from the Arctic, the immediate focus shifts to transforming the prototypes and decisions made at Soldøgn into production-ready code. The coming weeks will be dedicated to hardening client implementations against the new specifications, finalizing test coverage, and merging the draft Pull Requests (PRs) into the main codebase.
Final decisions regarding critical values such as the 200 million gas limit target and the definitive repricing numbers will be publicly discussed and confirmed on the upcoming AllCoreDevs calls, which are anticipated to be major topics in the weeks ahead.
The Soldøgn Interop in Svalbard stands as a testament to the dedication and collaborative spirit of the Ethereum core development community. The successful hardening of Glamsterdam’s core components, particularly the significant progress towards a 200 million gas limit, marks a pivotal moment in Ethereum’s journey towards enhanced scalability and a more efficient, accessible decentralized future. The unique environment and intense focus undoubtedly accelerated development, a success story that will soon be chronicled in the forthcoming interop documentary.
