Rollup withdrawals: 1–2 day upgrade to speed Layer‑2 adoption
The proposed updates aim to shorten withdrawal times for Stage 1 optimistic rollups from seven days to 1-2 days to improve Layer 0 usability and reduce capital lockup. While this enhances user experience and lowers reliance on custodial bridges, critics warn of reduced time for fraud proof submissions. Stage 2 will maintain longer delays to ensure stronger security guarantees. Recommendations include tuning challenge periods, increasing incentives for independent watchers, and phased testing. Longer-term solutions highlight proof aggregation and improved tools for efficient dispute handling. Vitalik Buterin's proposal stresses preserving the dispute model in Stage 1 while promoting faster, low-risk exits, with community reviews and audits determining the final implementation timeline.
Layer-1
Introduction: Goals of the Rollup Update Proposal
Recent proposals seek to shorten rollup withdrawals for Stage 1 optimistic rollups to 1–2 days while keeping Stage 2 at 7 days. The main objectives include improving Layer-2 usability and reducing friction for traders and DeFi users. By reducing withdrawal times, Layer-2 platforms aim to become more accessible and efficient for everyday use.
Details of the Proposal
Cutting withdrawal times from 7 days to 1–2 days would significantly reduce capital lockup, making Layer-2 products more appealing. The proposal—attributed to Vitalik Buterin—specifically targets Stage 1 rollups while maintaining Stage 2 as conservative for stronger finality guarantees. Advocates argue that shorter withdrawal windows lower reliance on custodial bridges and improve user experience (UX). However, critics warn that this would potentially shrink the time available for submitting fraud proofs.
Preserving Security for Stage 2 Rollups
The proposal emphasizes operational updates that preserve the dispute model while shortening wait times for users. Practical recommendations include:
- Tuning challenge windows for routine transfers.
- Increasing incentives for independent watchers.
- Phasing changes through testnets to monitor impacts.
The overall approach ensures that Stage 1 rollups can offer faster exits for low-risk actions without undermining core fraud-proof mechanics.
Future Enhancements with Proof Aggregation and Tooling
Long-term solutions involve ideas such as proof aggregation and improved tooling to batch disputes, ultimately reducing on-chain costs. These upgrades, which are part of broader Ethereum rollup discussions, could enable faster cross-L2 movements while preserving settlement guarantees. However, this requires coordinated improvements among sequencers, watchers, and other critical components.
Technical Challenges and Gradual Implementation
A shorter withdrawal window (1–2 days) increases pressure on sequencers and watchers, and necessitates coordinated upgrades for clients and operators. As Vitalik Buterin explained in “An Incomplete Guide to Rollups” (5 January 2021):
“The contract starts a challenge period, during which anyone can try to use other Merkle branches to invalidate the exit.”
This principle underscores why Stage 2 should retain longer delays for security reasons, while Stage 1 pilots faster withdrawal times. Any timeline for implementation depends on community reviews, audits, and phased testing before rolling out changes to the mainnet.