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

# Incremental Authorization

Incremental authorization allows merchants to **increase the authorized amount** after the initial payment authorization — ideal for use cases like:

* Hotel bookings
* Car rentals
* Any service where the final charge may vary

This prevents payment disruptions and avoids re-authentication from the customer.

***

## ✅ Why Use Incremental Authorization?

| Benefit                   | Description                                                                                        |
| ------------------------- | -------------------------------------------------------------------------------------------------- |
| **Flexible Payments**     | Add charges in real-time (e.g., mini-bar charges, longer stay).                                    |
| **Improved UX**           | Avoid re-directing customers or asking for re-authentication.                                      |
| **Simplified Settlement** | All incremental amounts are combined with the original authorization into **a single settlement**. |

***

## ⚠️ Prerequisites

* Your business **must operate outside Strong Customer Authentication (SCA) regions**.
* Supported **only for card payments** and **specific networks/connectors**.
* Check connector-specific documentation to confirm support.

***

## 🛠️ How to Use Incremental Authorization

### 🧩 Step 1: Enable during payment creation

Use the `request_incremental_authorization` flag in the `/payments` create request.

```bash theme={"system"}
curl --request POST \
  --url https://api.test.switch.vaultera.co/payments \
  --header 'Content-Type: application/json' \
  --header 'api-key: <api-key>' \
  --data '{
    "amount": 6540,
    "authentication_type": "three_ds",
    "currency": "USD",
    "request_incremental_authorization": true
}'
```

***

### 🔍 Step 2: Check if allowed

In the payment creation response, look for the field:

```json theme={"system"}
"incremental_authorization_allowed": true
```

This indicates whether the selected connector supports incremental authorization for that transaction.

***

### ➕ Step 3: Make an incremental authorization request

Once allowed, you can add more funds using this endpoint:

```bash theme={"system"}
curl --request POST \
  --url https://api.test.switch.vaultera.co/payments/{payment_id}/incremental_authorization \
  --header 'Content-Type: application/json' \
  --header 'api-key: <api-key>' \
  --data '{
    "amount": 6540,
    "reason": "Extended stay"
}'
```

> Replace `{payment_id}` with your actual payment ID and provide a meaningful `reason`.

***

## 📌 Notes

* Each incremental authorization must follow the initial authorization.
* The cumulative amount across authorizations cannot exceed network or connector limits.
* All charges will be captured together during final capture.