Tanssi’s Decentralised Sequencer

Reliable, Fair & Institution-Grade Block Production

Every modern L1, roll-up, or appchain ultimately lives or dies by its sequencer, the component that orders transactions into blocks. When that component is centralised, it becomes a single point of failure, a censorship choke-point, or a MEV monopoly.

Arbitrum’s sole sequencer stalled for over an hour in December 2023, freezing the entire network. A single operator can include, delay, or omit transactions at will, jeopardising neutral market access. Even optimistic-roll-up documentation warns users they must “trust the Sequencer operates honestly.” With no competition, the operator pockets all ordering fees. Coinbase, which exclusively controls the Base sequencer, is already earning multi-million in monthly top-line revenue from that privilege alone.

These weaknesses do more than annoy power users; they block institutional entry by introducing operational, regulatory, and reputational risks.

A decentralised sequencing service

Tanssi manages a global Sequencer Pool to eliminate single-operator dependence. Two or more sequencers are reassigned every session by Tanssi Orchestrarion Layer to guarantee the liveness of block production. Operators validate the Candidate Block to check if the author is an authorized sequencer, if the state proofs match Tanssi's state, and if the transactions are valid.

Tanssi approaches the problem from first principles and treats block production as an orchestrated, decentralised service rather than a privileged role. How it works on Tanssi:

• Decentralized pool where anyone can register a sequencer, stake, and join the global pool managed by Tanssi. This eliminates single-operator dependency and fosters open competition.

• Multi-sequencer per network, where each Tanssi-powered chain is served by two or more sequencers simultaneously (mainnet aims to assign five per chain, with a hard floor of two). Hot redundancy guarantees liveness even if one node fails.

• Deterministic rotation with a stake-weighted list is shuffled and re-assigned every session. The next assignment is published one session in advance, and warp-sync lets nodes fast-sync to new chains. This reduces long-term collusion, spreads revenue, and ensures fair access for new entrants.

• An external finality layer such that all candidate blocks are validated and finalised by Symbiotic restakers, producing on-chain candidate receipts that any light client can audit. This separates ordering from settlement, adding an Ethereum-grade security back-stop.

• Transparent economics with registration fee, per-session assignment, and per-block execution fixed on-chain. Networks can add tips to jump the queue during congestion. This provides a predictable cost model for builders and market-based prioritisation under load.

Eliminating the classic failure & censorship modes

Centralized roll-ups are susceptible to critical vulnerabilities, including single points of failure where a single machine crash or legal injunction can halt the entire chain, as exemplified by the Arbitrum outage. They also present censorship risks, allowing operators to reorder or drop transactions silently, forcing users to "escape" via Layer 1, a process that can take hours or even days to complete.

Furthermore, centralized roll-ups often involve opaque MEV (Maximal Extractable Value) capture, with fees flowing to a single corporate entity, making it impossible for users to verify revenue distribution or transaction ordering rules.

In contrast, Tanssi Sequencing offers robust solutions to these challenges. By implementing multiple active sequencers, it ensures continuous block production even if one fails, with automatic hand-off at every session boundary, so there’s no recovery gap at all. To combat censorship, sequencers rotate on a schedule, are economically staked, and have every block verified by the Symbiotic restaker validator set; any deviation is recorded on-chain, leading to potential slashing and removal. Tanssi also promotes transparent MEV capture by automatically distributing revenue among assigned sequencers and storing receipts on-chain, enabling auditable ordering for post-trade compliance. These advancements are achieved without sacrificing speed or bloating Layer 1, boasting a 6-second average block time and deterministic finality through Symbiotic, which delivers both high speed and security.

Aligning incentives for builders, operators, and users

Tanssi is designed to create a harmonious ecosystem where the interests of all participants, builders, operators, and end-users, are intrinsically aligned. This is achieved through a carefully constructed framework that offers distinct advantages to each group.

• For builders – Launching an application-specific chain on Tanssi means no sequencer bootstrapping and no economic security bootstrapping, as all Tanssi appchains benefit from the same security level regardless of their size, TVL, or usage. Yet, you still retain runtime-level control (thanks to Substrate) and can forkless upgrade at will.
  

• For operators – Staking in the pool exposes you to multiple revenue streams across many chains, rather than betting on the success of one roll-up. Economic risk is diversified, and rotation keeps rewards reasonably egalitarian.
  

• For end-users – Multi-sequencer, externally-verified blocks give stronger guarantees of data availability, deterministic reorg-resistant finality, and lower censorship probability - properties institutions explicitly require for regulated assets.

Future-Proofing Against MEV

Because block production is already a modular service, Tanssi can adopt shared or threshold-encrypted mempools without a hard-fork of every deployed chain. Future road-map items under consideration include:

1. Threshold-EVM pre-confirmation - hide trade order until after inclusion to neutralise sandwich attacks.

2. Open auction for block space - let searchers bid on bundles, while the protocol redistributes proceeds to network treasuries instead of private sequencers.

   
   

The key point is that Tanssi’s architecture is extensible; roll-ups with single sequencers must redesign fundamental contracts to achieve similar goals.

In practice, Tanssi's design translates into several key benefits: it ensures higher uptime through redundant active sequencers and automatic warp-sync hand-off, making chain liveness resilient to various failures; it provides on-chain auditability by storing every assignment, receipt, and state root in Tanssi, offering cryptographic evidence for compliance; it delivers cost efficiency by allowing builders to pay only for consumed blocks and utilizing tipping for market-driven fairness during peak demand; and finally, it guarantees credible neutrality, preventing any single entity from vetoing transactions or monopolizing MEV, which is crucial for traditional finance and real-world asset issuers.

Sequencing as infrastructure, not privilege

The last 18 months of roll-up growth have shown that centralised sequencers are expedient but fragile. Tanssi flips the script by treating block production exactly like cloud orchestration: an elastic, multi-tenant service where any staked operator can compete and every chain enjoys built-in redundancy.

By combining a decentralised, rotating sequencer pool, Symbiotic-backed shared security finality, and transparent on-chain economics, Tanssi delivers a sequencing layer that is harder to censor, harder to break, and easier to trust than today’s single-operator roll-ups. 

For developers and institutions that need both autonomy and reliability, Tanssi is not just an alternative, but a substantial upgrade.