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

# Learn

> Concepts, architecture, and use case narratives for Stable. What it is, how it differs from Ethereum, and the mental models behind USDT0 as gas.

## Foundation

<CardGroup cols={2}>
  <Card title="Overview" icon="compass" href="/en/explanation/overview">
    What Stable is and how to read this documentation.
  </Card>

  <Card title="Key features" icon="list-checks" href="/en/explanation/key-features">
    Headline specs: single-slot finality, USDT0 as gas, full EVM compatibility.
  </Card>

  <Card title="Difference from Ethereum" icon="git-compare" href="/en/explanation/ethereum-comparison">
    What stays the same and what changes when you port from Ethereum.
  </Card>

  <Card title="Core concepts" icon="book-open" href="/en/explanation/core-concepts">
    USDT0 dual role, guaranteed blockspace, transfer aggregator, finality.
  </Card>
</CardGroup>

## USDT0 behavior

<CardGroup cols={2}>
  <Card title="USDT0 behavior on Stable" icon="scale" href="/en/explanation/usdt0-behavior">
    Dual-role balance, reconciliation events, and contract design rules.
  </Card>

  <Card title="USDT as gas" icon="fuel" href="/en/explanation/usdt-as-gas-token">
    Why Stable uses USDT0 to pay for gas and what that means for fees.
  </Card>

  <Card title="Flow of funds" icon="arrow-right-left" href="/en/explanation/flow-of-funds">
    How USDT moves end-to-end across Stable.
  </Card>

  <Card title="USDT0 features" icon="list" href="/en/explanation/usdt-features-overview">
    Every USDT0-specific feature with links to each.
  </Card>
</CardGroup>

## Architecture

<CardGroup cols={2}>
  <Card title="Technical overview" icon="layers" href="/en/explanation/tech-overview">
    Consensus, execution, database, and RPC layers in one page.
  </Card>

  <Card title="Core optimizations" icon="cpu" href="/en/explanation/core-optimization-overview">
    The performance work behind sub-second finality.
  </Card>

  <Card title="Finality" icon="lock" href="/en/explanation/finality">
    Single-slot finality, reorg behavior, and what "confirmed" means.
  </Card>

  <Card title="Gas pricing" icon="calculator" href="/en/explanation/gas-pricing">
    Base-fee-only model priced in USDT0.
  </Card>
</CardGroup>

## Use case narratives

<CardGroup cols={2}>
  <Card title="Payments" icon="credit-card" href="/en/explanation/use-case-payments">
    Why Stable fits P2P, subscriptions, invoices, and pay-per-call.
  </Card>

  <Card title="Payroll" icon="users" href="/en/explanation/use-case-payroll">
    Batched and scheduled payroll runs on Stable.
  </Card>

  <Card title="Sponsored transactions" icon="zap" href="/en/explanation/use-case-sponsored">
    Letting applications cover gas for their users.
  </Card>

  <Card title="Private transfers" icon="shield" href="/en/explanation/use-case-private">
    Upcoming confidential payment flows.
  </Card>
</CardGroup>

<CardGroup cols={3} />