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

# Payments Overview

> Understand how Vaayu moves a payment through its lifecycle.

Vaayu gives developers a simple API for creating and tracking payments without requiring your application to manage the underlying payment infrastructure directly.

<CardGroup cols={3}>
  <Card title="Direct Payments" icon="arrow-right">
    Send a payment directly to a recipient through the Vaayu API.
  </Card>

  <Card title="Payment Status" icon="clock">
    Track a transaction from pending to confirmed or failed.
  </Card>

  <Card title="Webhooks" icon="webhook">
    Receive transaction updates automatically at your registered endpoint.
  </Card>
</CardGroup>

## Payment flow

```text theme={null}
Your application
      ↓
Vaayu API
      ↓
Payment created
      ↓
Transaction ID
      ↓
Pending
      ↓
Confirmed / Failed
      ↓
Webhook notification
```

## Authentication

Authenticated requests use your Vaayu API key in the `x-api-key` header.

```bash theme={null}
curl -X POST "https://vaayuapi.onrender.com/send-payment"   -H "x-api-key: sk_test_xxxxxxxxxxxxxxxxxxxx"   -H "Content-Type: application/json"   -d '{
    "amount": 100,
    "to": "0x..."
  }'
```

Keep your API key on your server. Never expose it in browser or mobile application code.

<Card title="Authentication" icon="key" href="/authentication">
  Learn how API keys work and how to keep them secure.
</Card>

## Payment lifecycle

| Status | Meaning |
| - | - |
| `pending` | The payment has been created and is being processed. |
| `confirmed` | The payment has completed successfully. |
| `failed` | The payment could not be completed. |

## Tracking payments

After creating a payment, save the transaction hash returned by Vaayu.

You can then:

1. Query the transaction status.
2. Receive updates through your registered webhook.
3. Use both methods together for additional reliability.

## Sandbox

During development, use the Vaayu sandbox/test environment rather than real-value payments.


This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.