> ## 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.

# Payments guides

> All payment guides, concepts, and references: Send USDT0, P2P, subscriptions, invoices, pay-per-call, bridging, and zero-gas.

Every guide, concept, and reference under the Payments tab, grouped by what you're trying to do.

## Send and transfer

<CardGroup cols={2}>
  <Card title="Send your first USDT0" icon="send" href="/en/tutorial/send-usdt0">
    Native and ERC-20 transfers on the same balance.
  </Card>

  <Card title="Zero gas transactions" icon="zap" href="/en/how-to/zero-gas-transactions">
    Transfer USDT0 with the fee covered by a Gas Waiver.
  </Card>

  <Card title="Work with USDT0 as gas" icon="fuel" href="/en/how-to/work-with-usdt-gas">
    Construct transactions correctly: priority tip 0, `value` in USDT0.
  </Card>

  <Card title="Bridge USDT0 to Stable" icon="bridge" href="/en/tutorial/bridge-usdt0">
    Bridge from Ethereum Sepolia using LayerZero OFT.
  </Card>
</CardGroup>

## Build a payment flow

<CardGroup cols={2}>
  <Card title="Learn P2P payments" icon="users" href="/en/how-to/build-p2p-payments">
    Wallet + send + receive + history in one app.
  </Card>

  <Card title="Subscribe and collect" icon="repeat" href="/en/how-to/subscribe-and-collect">
    Pull-based recurring billing via EIP-7702.
  </Card>

  <Card title="Paying with invoice" icon="file-text" href="/en/how-to/pay-with-invoice">
    ERC-3009 with deterministic nonces for invoice settlement.
  </Card>

  <Card title="Build a pay-per-call API" icon="code" href="/en/how-to/build-pay-per-call">
    Monetise HTTP endpoints with x402 middleware.
  </Card>
</CardGroup>

## Protocols and references

<CardGroup cols={2}>
  <Card title="ERC-3009" icon="signature" href="/en/explanation/erc-3009">
    Transfer With Authorization: the signed-settlement primitive.
  </Card>

  <Card title="x402 (HTTP-native payments)" icon="globe" href="/en/explanation/x402">
    Server responds 402, client signs, facilitator settles on-chain.
  </Card>

  <Card title="P2P payments reference" icon="book-open" href="/en/reference/p2p-payments">
    Model overview and comparison to traditional rails.
  </Card>

  <Card title="Subscriptions reference" icon="calendar" href="/en/reference/subscriptions">
    Pull-based billing model and trade-offs.
  </Card>

  <Card title="Invoices reference" icon="receipt" href="/en/reference/invoices">
    Deterministic-nonce settlement model.
  </Card>

  <Card title="Pay-per-call reference" icon="receipt-text" href="/en/reference/pay-per-call">
    x402 pricing and endpoint discovery model.
  </Card>

  <Card title="Upcoming use cases" icon="clock" href="/en/explanation/upcoming-use-cases">
    Guaranteed settlement, confidential payments, agent-to-agent.
  </Card>
</CardGroup>