🌐 Decentralization: Shared Sequencers

Discover the path from centralized to decentralized sequencing

Watch how rollups batch transactions

🛤️ Path to Decentralization

Most L2s start with centralized sequencers and gradually decentralize. Understanding this progression helps anticipate future protocol designs and trade-offs.

🚀 Decentralization Journey

Navigate through the stages of sequencer decentralization. Each stage brings different trade-offs between speed, security, and decentralization.

👤

Single Sequencer

One entity controls transaction ordering

Stage 1 of 4
Censorship Risk
100/100
Liveness
50/100
Performance
80/100
Complexity
20/100
Advantages
  • Simple
  • Fast
  • Low latency
Disadvantages
  • Centralized
  • Single point of failure
  • High censorship risk
Examples:
Optimism (early)Arbitrum (early)zkSync Era

🔬 Technical Approaches

Based Rollups

L1 validators sequence L2 transactions directly. Inherits L1 decentralization instantly.

Shared Sequencing

Multiple L2s share a decentralized sequencer network (Espresso, Astria).

Threshold Encryption

Transactions encrypted until block committed, preventing MEV extraction.

⚡ Current Status (2024)

Most L2s: Single Sequencer
Optimism, Arbitrum, zkSync, Polygon zkEVM
Some Testing Rotation
Metis with PoS-based rotation model
Future: Full Decentralization
Target: 2025-2026 for major L2s

🎯 Key Challenges

⚖️

Performance vs Decentralization

Decentralized consensus adds latency. Need innovations to maintain speed.

💰

Economic Security

Sequencers need sufficient stake and incentives to ensure honest behavior.

🔗

Cross-Chain Coordination

Shared sequencing requires complex coordination between multiple rollups.

🛠️

Implementation Complexity

Building robust, decentralized systems is significantly harder than centralized ones.

← MEV & Censorship