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

# Quickstart

> Deploy your first Saturn-powered agent in 5 minutes

## Prerequisites

* Node.js 18+
* npm or yarn

## Installation

Install the Saturn SDK:

```bash theme={null}
npm install @saturn-pay/sdk
```

## 1. Create an Agent

Sign up and get an authenticated client:

```typescript theme={null}
import { Saturn } from '@saturn-pay/sdk';

const { saturn, apiKey } = await Saturn.signup({
  name: 'my-first-agent',
  baseUrl: 'https://api.saturn-pay.com',
});

// Save this API key — it's only shown once
console.log('Your API key:', apiKey);
```

<Warning>
  Store your API key securely. It cannot be retrieved after signup.
</Warning>

## 2. Fund Your Wallet

Add credits via card or Lightning:

<Tabs>
  <Tab title="Card (USD)">
    ```typescript theme={null}
    const checkout = await saturn.wallet.fundCard({
      amountUsdCents: 1000 // $10
    });

    console.log('Pay here:', checkout.checkoutUrl);
    // Opens Stripe checkout
    ```
  </Tab>

  <Tab title="Lightning (sats)">
    ```typescript theme={null}
    const invoice = await saturn.wallet.fund({
      amountSats: 10000
    });

    console.log('Pay this invoice:', invoice.paymentRequest);
    // Pay with any Lightning wallet
    ```
  </Tab>
</Tabs>

## 3. Make Your First Call

Use a capability:

```typescript theme={null}
const result = await saturn.reason({
  prompt: 'Explain quantum computing in one sentence',
});

console.log(result.data.content);
// → "Quantum computing uses quantum mechanical phenomena..."

console.log(`Cost: ${result.metadata.chargedSats} sats`);
console.log(`Balance remaining: ${result.metadata.balanceAfter} sats`);
```

## 4. Set Budget Limits

Protect against runaway costs:

```typescript theme={null}
await saturn.policies.update(agentId, {
  maxPerCallSats: 500,      // Max $0.50 per call
  maxPerDaySats: 5000,      // Max $5.00 per day
  allowedCapabilities: ['reason', 'search', 'read'],
});
```

## Complete Example

```typescript theme={null}
import { Saturn, SaturnPolicyDeniedError } from '@saturn-pay/sdk';

async function main() {
  // Create agent
  const { saturn, apiKey } = await Saturn.signup({
    name: 'research-bot',
    baseUrl: 'https://api.saturn-pay.com',
  });

  console.log('API Key:', apiKey);

  // Fund wallet
  const checkout = await saturn.wallet.fundCard({ amountUsdCents: 500 });
  console.log('Fund your wallet:', checkout.checkoutUrl);

  // Wait for payment (in real app, use webhook)
  await new Promise(r => setTimeout(r, 60000));

  // Use capabilities
  try {
    // Search the web
    const search = await saturn.search({
      query: 'latest AI research papers'
    });
    console.log('Found:', search.data.results.length, 'results');

    // Read a page
    const read = await saturn.read({
      url: search.data.results[0].url
    });
    console.log('Content length:', read.data.content.length);

    // Synthesize
    const reason = await saturn.reason({
      prompt: `Summarize this: ${read.data.content.slice(0, 2000)}`,
    });
    console.log('Summary:', reason.data.content);

  } catch (err) {
    if (err instanceof SaturnPolicyDeniedError) {
      console.log('Budget exceeded:', err.message);
    } else {
      throw err;
    }
  }
}

main();
```

## Next Steps

<CardGroup cols={2}>
  <Card title="Authentication" icon="key" href="/authentication">
    Learn about API key management
  </Card>

  <Card title="Capabilities" icon="wand-magic-sparkles" href="/capabilities/overview">
    Explore all 10 capability verbs
  </Card>

  <Card title="Budgets & Caps" icon="gauge" href="/concepts/budgets-and-caps">
    Configure spend limits
  </Card>

  <Card title="Research Agent Tutorial" icon="flask" href="/tutorials/research-agent">
    Build a budget-capped research agent
  </Card>
</CardGroup>