curl -u [YOUR_KEY_ID]:[YOUR_KEY_SECRET] \
-X POST https://api.razorpay.com/v1/payments/pay_29QQoUBi66xm2f/refund \
-H 'Content-Type: application/json' \
-d '{
  "amount":500100,
  "speed":"optimum",
  "receipt":"Receipt No. 31",
  "notes":{
    "notes_key_1":"Tea, Earl Grey, Hot",
    "notes_key_2":"Tea, Earl Grey… decaf."
  }
}'

RazorpayClient razorpay = new RazorpayClient("[YOUR_KEY_ID]", "[YOUR_KEY_SECRET]");

String paymentId = "pay_29QQoUBi66xm2f";

JSONObject refundRequest = new JSONObject();
refundRequest.put("amount",100);
refundRequest.put("speed","optimum");
refundRequest.put("receipt","Receipt No. #31");
JSONObject notes = new JSONObject();
notes.put("notes_key_1","Tea, Earl Grey, Hot");
notes.put("notes_key_2","Tea, Earl Grey… decaf.");
refundRequest.put("notes",notes);

Payment payment = razorpay.payments.refund(paymentId,refundRequest);

$api = new Api($key_id, $secret);

$api->payment->fetch($paymentId)->refund(array("amount"=> "100","speed"=>"optimum","notes"=>array("notes_key_1"=>"Beam me up Scotty.", "notes_key_2"=>"Engage"),"receipt"=>"Receipt No. 31"));

import razorpay
client = razorpay.Client(auth=("YOUR_ID", "YOUR_SECRET"))

client.payment.refund(paymentId,{
  "amount": "100",
  "speed": "optimum",
  "notes": {
    "notes_key_1": "Beam me up Scotty.",
    "notes_key_2": "Engage"
  },
  "receipt": "Receipt No. 31"
})

import ( razorpay "github.com/razorpay/razorpay-go" )
client := razorpay.NewClient("YOUR_KEY_ID", "YOUR_SECRET")

data := map[string]interface{}{
	"speed": "optimum",
  "notes": map[string]interface{}{
    "key_1": "value1",
    "key_2": "value2"
  },
	"receipt": "Receipt No. #12",
}
body, err := client.Payment.Refund("<paymentId>",100, data, nil)

require "razorpay"
Razorpay.setup('YOUR_KEY_ID', 'YOUR_SECRET')

paymentId = "pay_29QQoUBi66xm2f"

para_attr = {
  "amount": "100",
  "speed": "optimum",
  "notes": {
    "notes_key_1": "Beam me up Scotty.",
    "notes_key_2": "Engage"
  },
  "receipt": "Receipt No. 31"
}
Razorpay::Payment.fetch(paymentId).refund(para_attr)

var instance = new Razorpay({ key_id: 'YOUR_KEY_ID', key_secret: 'YOUR_SECRET' })

instance.payments.refund(paymentId,{
  "amount": "100",
  "speed": "optimum",
  "notes": {
    "notes_key_1": "Beam me up Scotty.",
    "notes_key_2": "Engage"
  },
  "receipt": "Receipt No. 31"
})

//initialize the SDK client
RazorpayClient client = new RazorpayClient("[YOUR_KEY_ID]", "[YOUR_KEY_SECRET]");

String paymentId = "pay_Z6t7VFTb9xHeOs";

Dictionary<string, object> refundRequest = new Dictionary<string, object>();
refundRequest.Add("amount",100);
refundRequest.Add("speed","optimum");
Dictionary<string, object> notes = new Dictionary<string, object>();
notes.Add("notes_key_1", "Tea, Earl Grey, Hot");
notes.Add("notes_key_2", "Tea, Earl Grey… decaf.");
refundRequest.Add("notes", notes);
refundRequest.Add("receipt","Receipt No. 31");

Refund refund = client.Payment.Fetch(paymentId).Refund(refundRequest);

razorpay refunds create pay_ABC123 --amount 50000 --speed optimum

{
  "id": "rfnd_FP8R8EGjGbPkVb",
  "entity": "refund",
  "amount": 500100,
  "currency": "INR",
  "payment_id": "pay_29QQoUBi66xm2f",
  "notes": {
    "notes_key_1": "Tea, Earl Grey, Hot",
    "notes_key_2": "Tea, Earl Grey… decaf."
  },
  "receipt": "Receipt No. 31",
  "acquirer_data": {
    "arn": null
  },
  "created_at": 1597078914,
  "batch_id": null,
  "status": "processed",
  "speed_processed": "normal",
  "speed_requested": "optimum"
}

{
    "error": {
        "code": "BAD_REQUEST_ERROR",
        "description": "_29QQoUBi66xm2f is not a valid id",
        "source": "business",
        "step": "payment_initiation",
        "reason": "input_validation_failed",
        "metadata": {}
    }
}