Key Takeaways - @realbarnakiss on Sequencer Design for Multi-Rollup ZeFi Applications Finality and Reorg Risk • @ethereum's lack of single-slot finality introduces reorg risk, which can result in valid ZK proofs being generated on dropped states - leading to double-spend vulnerabilities. • Rollups have more stable finality due to centralized sequencers; reorgs are rare but must still be accounted for in design. Rollup Inclusion Latency • Sequencer behavior varies: many rollups post batches only when full, causing unpredictable latencies. • Applications relying on these chains must account for variable confirmation times (e.g. @base posts every ~54s vs. others potentially taking minutes). Design Implications for Sequencers • To maintain usability, ZeFi protocols should adopt a hybrid sequencer approach: a slow, secure path based on finalized Ethereum blocks, and a fast, centralized sequencer for low-value or time-sensitive actions. • Dynamic confirmation rules (e.g. value-based thresholds) can optimize user experience while mitigating risk. Use of Light Clients and Full Nodes • Light clients (e.g. Helios) offer trust-minimized state verification but with weaker guarantees. • Full nodes provide stronger security by performing full block execution - critical for preventing sequencer misbehavior. zkVM Integration • Zero-knowledge proofs can be used to encode and enforce protocol-level reorg protections across rollups. • Future architectures may incorporate real-time proving and programmable constraints to enhance security. Documentation and Tooling Gaps • Lack of standardized, deep documentation (especially on finality and reorg behavior) presents significant development hurdles. • @Optimism stack documentation has improved notably, serving as a model for others.