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

# Introduction To FLEX

> Build with FLEX APIs for wallet SSO, merchant collections, partner gateway flows, and switching services.

## Build with FLEX

FLEX helps you move money with wallet-native experiences and API-first payment rails.
You can use PayTag-based identity, direct payment requests, partner collection flows, and end-of-day settlement.

<Card icon="rocket" horizontal href="/sso/index" title="Start with wallet SSO">
  Launch payTag-based authentication, wallet access, transfers, and payment request flows.
</Card>

## Choose your integration path

<CardGroup cols={2}>
  <Card icon="wallet" href="/sso/index" title="Wallet SSO">
    Let users sign in with PayTag, access wallets, and transact inside your app.
  </Card>

  <Card icon="store" href="/merchant/index" title="Merchant API">
    Accept collections with payment requests (OneTap), QR code flows, and payTag resolution.
  </Card>

  <Card icon="cash-register" href="/partner/index" title="Partner gateway API">
    Collect funds from FLEX wallet users using partner and terminal-oriented endpoints.
  </Card>

  <Card icon="arrows-rotate" href="/idaas/index" title="Switching service (IDAAS)">
    Route cross-application transactions with participant acceptance and daily settlement.
  </Card>
</CardGroup>

## What you can build

<CardGroup cols={2}>
  <Card icon="user-check" href="/sso/authentication" title="Authentication and consent">
    Authenticate users, capture consent, and issue tokens for secure API access.
  </Card>

  <Card icon="money-bill-transfer" href="/sso/transaction" title="Wallet and transfer flows">
    Create wallet-native transfer experiences for P2P and merchant-related use cases.
  </Card>

  <Card icon="qrcode" href="/merchant/qr-code" title="QR and payment requests">
    Generate payment requests and QR payloads for fast in-app or assisted checkout.
  </Card>

  <Card icon="scale-balanced" href="/idaas/payments" title="Settlement-aware switching">
    Orchestrate transaction honoring and reconcile net positions during settlement cycles.
  </Card>
</CardGroup>

## Integrate in four steps

<Steps>
  <Step title="Pick your product surface">
    Choose **Wallet SSO**, **Merchant API**, **Partner API**, or **IDAAS** based on your business model.
  </Step>

  <Step title="Set up credentials and authentication">
    Configure your `x-client-id` and `x-api-key`, then complete the required auth flow.
  </Step>

  <Step title="Implement core transaction journeys">
    Build your required flow: wallet transfers, payment requests, partner collections, or switching routes.
  </Step>

  <Step title="Go live with webhooks and monitoring">
    Verify webhook signatures, handle retries, and track transaction and settlement states.
  </Step>
</Steps>

## API references and SDK

<CardGroup cols={2}>
  <Card icon="file-code" href="/api-reference/wallet-sso" title="Wallet SSO API reference">
    Explore request and response schemas for the SSO API surface.
  </Card>

  <Card icon="file-code" href="/api-reference/merchant" title="Merchant API reference">
    Review Merchant endpoints for payment requests and QR flows.
  </Card>

  <Card icon="file-code" href="/api-reference/partner" title="Partner API reference">
    Review Partner and terminal endpoints for collection workflows.
  </Card>

  <Card icon="mobile-screen" href="/sdk/wallet" title="Flutter SDK">
    Embed FLEX wallet onboarding, login, and transaction experiences in your Flutter app.
  </Card>
</CardGroup>

## Need help?

If you need credentials or architecture guidance, email `developer@yourflexpay.com`.