> ## Documentation Index
> Fetch the complete documentation index at: https://docs.arc.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Deterministic finality and settlement

> Arc's deterministic finality delivers irreversible transaction settlement in under one second.

Arc provides deterministic finality: every transaction is either unconfirmed or
final, with no intermediate state. This guarantee comes from the network's
[consensus layer](/arc/concepts/consensus-layer), which uses a Byzantine Fault
Tolerant (BFT) consensus protocol — once two-thirds or more of validators sign
off on a block, that block is irreversible. Every transaction in a committed
block is immediately and irreversibly settled. There are no confirmation
windows, no reorganization risk, and no probabilistic uncertainty.

## Finality comparison

Arc's [Malachite BFT consensus](/arc/concepts/consensus-layer), a Byzantine
Fault Tolerant protocol, finalizes blocks in under one second. This is orders of
magnitude faster than the finality guarantees on other networks:

| Network               | Finality  | Notes                                                               |
| :-------------------- | :-------- | :------------------------------------------------------------------ |
| **Arc**               | \<1 s     | Deterministic. Final on commit.                                     |
| **Ethereum L1**       | 12-15 min | Two epochs of attestations required for finality.                   |
| **Typical L2 rollup** | \~7 days  | Withdrawal finality depends on the challenge or proof window to L1. |

## Use cases

Sub-second deterministic finality enables use cases that are impractical on
slower networks:

| Use case               | How finality helps                                                                                                             |
| :--------------------- | :----------------------------------------------------------------------------------------------------------------------------- |
| Point-of-sale payments | A merchant can confirm payment and release goods without waiting for additional block confirmations.                           |
| Crossborder settlement | Transfers between counterparties finalize instantly, eliminating the settlement windows that introduce counterparty risk.      |
| Institutional clearing | Trades and margin calls settle with immediate certainty, matching the expectations of traditional financial infrastructure.    |
| Composable workflows   | Multi-step onchain flows (such as swap-then-bridge) execute sequentially without polling or confirmation delays between steps. |

## Developer benefits

Deterministic finality simplifies application design by removing the edge cases
that probabilistic chains force you to handle.

<CardGroup cols={2}>
  <Card title="No reorg handling" icon="shield-check">
    You don't need retry logic, rollback mechanisms, or confirmation-count
    thresholds. A confirmed transaction stays confirmed.
  </Card>

  <Card title="Immediate offchain effects" icon="bolt">
    Safely trigger downstream actions (webhooks, database writes, notifications)
    as soon as a block is committed, without waiting for additional
    confirmations.
  </Card>

  <Card title="Simplified state management" icon="toggle-on">
    Your application only needs to track two transaction states — unconfirmed
    and final — rather than tracking a sliding confirmation window.
  </Card>

  <Card title="Enterprise compliance" icon="file-certificate">
    Settlement finality is auditable and provable, meeting the assurance
    requirements of regulated financial institutions.
  </Card>
</CardGroup>