Faster Blockchains and the Sequencer Problem
Faster blockchains are great. Until you realize one sequencer controls the flow.
Most rollups today rely on a single sequencer to order transactions. On paper, this makes sense: it’s simple, efficient, and gets the job done. But when you zoom out, the risks become clear:
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Centralization risk → A single entity can decide which transactions go first, or even censor some entirely.
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Failure risk → If that sequencer goes offline, the whole rollup stalls.
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MEV extraction → With full control of ordering, the sequencer can reorder trades for profit.
Why Businesses Should Care
For businesses building on rollups, these aren’t edge cases. They affect fairness, uptime, and ultimately user trust. Imagine a DeFi protocol where one player can consistently front-run trades, or a game where certain actions lag because the sequencer bottlenecked. That’s not the Web3 we promise users.
Enter Shared Sequencing
So what’s the alternative? This is where shared sequencing comes into the picture. Instead of one sequencer per rollup, multiple participants collectively agree on transaction order.
How Shared Sequencing Works
Technically, this can be set up by:
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Running a decentralized network of sequencers that use consensus to agree on ordering.
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Using batching techniques to bundle transactions fairly before sequencing.
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Coordinating across rollups so that ordering is consistent, enabling cross-rollup composability.
The Benefits of Shared Sequencing
And the upside is significant…
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Fairer ordering reduces MEV abuse.
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Reliability improves since there’s no single point of failure.
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Cross-rollup applications (trading, gaming, composable DeFi) become much more practical.
Emerging Projects Leading the Way
Projects like Espresso and Astria are already working on this, and it’s likely we’ll see more experiments.
The Bigger Picture
But the bigger point is this: as rollups become the backbone of Ethereum scaling, who controls sequencing may matter as much as throughput itself.
