> For the complete documentation index, see [llms.txt](https://docs.leanx.io/api-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.leanx.io/api-docs/cloud-payment/bill/callback.md).

# Callback

Upon every successful transaction, a callback will be send to the link that you provided earlier through parameter 

```postman_json
callback_url
```

However, LeanX callback mechanism will send an encoded JWT message instead of plain text to provided link, which need to be decoded with a **hash key** before it can be read.  Below are the sample of callback response before and after encoding and decoding process.

{% hint style="info" %}
**Hash Key** can be retrieved in your portal dashboard under **API** page.
{% endhint %}

Sample callback response before JWT decode

{% code overflow="wrap" fullWidth="false" %}

```json
{
   "data":"eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.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.sbYhLQgR6Y4MRlAyMaVPHNWOc3Bp9NvFyKOFF-npyIU",
   "response_code":2100
}
```

{% endcode %}

Sample callback response after JWT decode

```json
{
  "invoice_no": "BP1701155880uBMwB9q0",
  "client_data": {
    "merchant_invoice_no": "LXPAYeubb68W1701155842uNHhS",
    "uuid": "8ef4ce50-aebb-4d8c-b142-4fa2a089fd06",
    "order_id": "None"
  },
  "invoice_status_id": 2,
  "invoice_type_id": 1,
  "invoice_type": "NORMAL_COLLECTION",
  "invoice_status": "SUCCESS",
  "amount": "456.20",
  "payment_model_reference_id": 1,
  "rate_type_reference_id": 2,
  "payment_service_id": 89,
  "client_redirect_url": "https://www.yourdomain.com/return-page",
  "client_callback_url": "https://www.yourdomain.com/api-callback-url",
  "client_transaction_details": null,
  "prefund_collection": {
    "item": null,
    "response_code": 2100
  },
  "description": null,
  "card_token": null,
  "fpx_buyer_name": "MOHD IZMAN BIN MD TEH",
  "fpx_transaction_id": "2505061440020644",
  "fpx_debit_auth_code": "00",
  "fpx_credit_auth_code": "00",
  "fpx_debit_status": "Approved",
  "transaction_response_time": "28 November 23 03:18:03 PM",
  "original_transaction_response_time": "2023-11-28 15:18:03"
}
```

{% hint style="info" %}
If you are integrating via your application, the **hash key will always be an identifier or a signature** to ensure that the callback was intended to be send to you. If the hash key is incorrect, it might be coming from unknown sources.
{% endhint %}


---

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