# Rezepte (https://dev.cosmospay.lat/docs/de/sdk/server/recipes/)

> Praktische End-to-End-Rezepte: Checkout, Spenden, idempotente Webhooks, Abgleich und Testnet/Mainnet.

Copy-and-paste-Lösungen für häufige Szenarien, zusammengesetzt aus den Bausteinen, die im Rest dieser Dokumentation beschrieben werden.

Copy-and-paste-fähige End-to-End-Muster. Alle Server-Snippets setzen voraus:

```ts
import { Client, Assets } from '@cosmosapp/pay_sdk';
const client = new Client({ apiKey: process.env.COSMOS_PAY_API_KEY });
```

## 1. Checkout (Server erstellt, Browser zahlt, Webhook bestätigt)

```ts
// server: create the intent for an order
export async function startCheckout(orderId: string, total: string) {
  const intent = await client.paymentIntents.createPay({
    destination: process.env.MERCHANT_ACCOUNT,
    amount: total,
    asset: Assets.USDC,
    reference: orderId,           // ties the intent to your order
    msg: `Order ${orderId}`,
  });
  return intent.toJSON();         // → send to the browser
}
```

```ts
// browser: complete it with the user's wallet
import { WebClient } from '@cosmosapp/pay_sdk/web';
const { txHash } = await new WebClient().pay(intentPayload);
await fetch('/api/confirm', { method: 'POST', body: JSON.stringify({ id: intentPayload.id, txHash }) });
```

```ts
// server: fulfill on the webhook (don't trust the browser alone)
client.webhooks.on('paymentIntentSucceeded', async (event) => {
  await markOrderPaid(event.data.reference, event.data.id);
});
```

## 2. Spende / Trinkgeldglas (offener Betrag)

```ts
const intent = await client.paymentIntents.createPay({
  destination: process.env.MERCHANT_ACCOUNT,
  asset: Assets.USDC,   // no amount → the wallet asks the user
  msg: 'Support us 💜',
});
// browser: await new WebClient().pay(intent, { amount: enteredAmount });
```

## 3. Idempotente Webhook-Verarbeitung

```ts
const processed = new Set<string>(); // use your DB in production
client.webhooks.on('event', (event) => {
  if (processed.has(event.id)) return; // event.id is stable, so dedupe on it
  processed.add(event.id);
  handle(event);
});
```

## 4. Eine Zahlung serverseitig abgleichen

```ts
// You received a txHash out-of-band (e.g. polled the browser). Finalize it:
const outcome = await client.paymentIntents.validate(intentId, { txHash });
if (!outcome.valid) {
  console.warn('payment not valid:', outcome.reason); // amount/destination/memo mismatch
}
```

## 5. Testnet vs. Mainnet

```ts
import { Assets, TestnetAssets } from '@cosmosapp/pay_sdk';
// dv_ key → testnet → use TestnetAssets.USDC
// prod_ key → mainnet → use Assets.USDC
const asset = process.env.COSMOS_PAY_API_KEY.startsWith('prod_') ? Assets.USDC : TestnetAssets.USDC;
```

## 6. Katalog: Produkte + Kunden

```ts
const product = await client.products.create({ name: 'Pro', amount: '49.00', assetCode: 'USDC', kind: 'recurring' });
const customer = await client.customers.create({ name: 'Acme', email: 'billing@acme.com', account: 'G...' });
// then create intents referencing the customer's account as destination/source.
```

## Referenzen

- [Client](https://dev.cosmospay.lat/docs/sdk/definitions/server/client/): Der Haupteinstiegspunkt des SDK. Ein einzelner, atomarer Client, der jede Ressource über ihren eigenen Manager bereitstellt (ein atomares Single-Client-Design).
- [WebClient](https://dev.cosmospay.lat/docs/sdk/definitions/web/web-client/)
- [Assets](https://dev.cosmospay.lat/docs/sdk/web/assets-wallets-addresses/): Typed asset / wallet catalog or address helper.
- [TestnetAssets](https://dev.cosmospay.lat/docs/sdk/web/assets-wallets-addresses/): Typed asset / wallet catalog or address helper.