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

# PayIn Callbacks

> Receive instant POST notifications on your HTTPS endpoint whenever a PayIn transaction changes status on FastFlowPe.

FastFlowPe sends real-time PayIn transaction status updates to a webhook endpoint of your choosing. Whenever a PayIn transaction reaches a terminal state, FastFlowPe automatically POSTs a JSON payload to your pre-configured HTTPS URL, so your system stays in sync without polling.

<Tip>
  **Quick Reference**

  **Protocol:** HTTPS only (HTTP endpoints are rejected)

  **Method:** `POST` with JSON body

  **Event:** PayIn transaction status change

  **Setup path:** Merchant Dashboard, Settings, Webhooks, Credit - PayIn, Update

  **Activation:** 2 to 3 minutes after saving
</Tip>

## How to Configure Your PayIn Callback URL

Register your PayIn webhook URL in the merchant dashboard before FastFlowPe can deliver PayIn callbacks to your server.

<Steps>
  <Step title="Log in to the merchant dashboard">
    Navigate to [https://go.fastflowpe.com/](https://go.fastflowpe.com/) and sign in with your merchant credentials.
  </Step>

  <Step title="Open Webhook Settings">
    From the left sidebar, click **Settings**, then select the **Webhooks** tab.
  </Step>

  <Step title="Enter your PayIn callback URL">
    Under **Credit - PayIn**, enter your HTTPS endpoint URL where you want FastFlowPe to deliver PayIn transaction callbacks.
  </Step>

  <Step title="Save the configuration">
    Click **Update** under **Credit - PayIn** to save your URL. Full path: **Login → Settings → Webhooks → Credit - PayIn → Update**.
  </Step>
</Steps>

<Note>
  Only HTTPS-enabled webhook URLs are accepted. HTTP endpoints will be rejected and will not receive any callbacks.
</Note>

<Tip>
  Allow 2 to 3 minutes after saving your callback URL for the configuration to take effect. The next PayIn event after that window will be delivered to your endpoint.
</Tip>

## PayIn Callback Payload

FastFlowPe uses a `POST` request with a JSON body for all PayIn callbacks.

```json PayIn Callback theme={"dark"}
{
  "transaction": {
    "id": "<transaction UUID>",
    "order_id": "<your order ID>",
    "amount": "500.00",
    "payment_type": "QR",
    "utr": "619704648408",
    "status": "SUCCESS",
    "transaction_details": "<customer info object>",
    "resp_message": "<parsed response>"
  }
}
```

## PayIn Payload Fields

<ResponseField name="id" type="string">
  The unique UUID of the PayIn transaction.
</ResponseField>

<ResponseField name="order_id" type="string">
  The order ID you submitted when creating the PayIn transaction.
</ResponseField>

<ResponseField name="amount" type="string">
  The transaction amount as a decimal string.
</ResponseField>

<ResponseField name="payment_type" type="string">
  The payment mode used (e.g., `QR`, `UPI`).
</ResponseField>

<ResponseField name="utr" type="string">
  The Unique Transaction Reference issued by the bank. `null` on failure.
</ResponseField>

<ResponseField name="status" type="string">
  The final transaction status. Either `SUCCESS` or `FAILED`.
</ResponseField>

<ResponseField name="transaction_details" type="object">
  An object containing customer information associated with the transaction.
</ResponseField>

<ResponseField name="resp_message" type="string">
  The parsed response message from the payment service provider.
</ResponseField>

<Tip>
  In production, rely on callbacks rather than polling the [PayIn Status](/collections/transaction-api/check-transaction) endpoint. Webhooks reduce latency, cut down on unnecessary API calls, and ensure your system reacts to transaction outcomes in real time.
</Tip>

<Note>
  Configuring PayOut callbacks? See [PayOut Callbacks](/webhooks/payout-callbacks).
</Note>