Sequencer
The service that orders transactions on a Layer 2 network. Currently often centralized, but projects are working on decentralizing them.
Example
Arbitrum's sequencer deciding which transactions go first, collecting fees, and sending batches to Ethereum.
Advanced Concepts
⚙️How It Works
- 1
Receive Transactions
Users submit transactions to the sequencer
- 2
Order & Execute
Sequencer decides transaction order and executes them
- 3
Batch
Transactions are batched together for efficiency
- 4
Post to L1
Batched data is posted to Ethereum for finality
⚠️Risks & Warnings
- •Centralized sequencers can censor your transactions
- •Sequencer downtime means the L2 stops working temporarily
- •MEV extraction by sequencers (front-running your trades)
- •Trust assumptions until decentralized sequencers are implemented