curl --request POST \
  --url https://sandbox.cashfree.com/bbps/cou/v1/billers/info \
  --header 'Content-Type: application/json' \
  --header 'x-api-version: <x-api-version>' \
  --header 'x-client-id: <api-key>' \
  --header 'x-client-secret: <api-key>' \
  --data '
{
  "biller_fetch_request": {
    "biller_id": [
      "OANSTOP00NAT01"
    ],
    "biller_category_name": [
      "DTH"
    ]
  }
}
'

import requests

url = "https://sandbox.cashfree.com/bbps/cou/v1/billers/info"

payload = { "biller_fetch_request": {
        "biller_id": ["OANSTOP00NAT01"],
        "biller_category_name": ["DTH"]
    } }
headers = {
    "x-api-version": "<x-api-version>",
    "x-client-id": "<api-key>",
    "x-client-secret": "<api-key>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'POST',
  headers: {
    'x-api-version': '<x-api-version>',
    'x-client-id': '<api-key>',
    'x-client-secret': '<api-key>',
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    biller_fetch_request: {biller_id: ['OANSTOP00NAT01'], biller_category_name: ['DTH']}
  })
};

fetch('https://sandbox.cashfree.com/bbps/cou/v1/billers/info', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://sandbox.cashfree.com/bbps/cou/v1/billers/info",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'biller_fetch_request' => [
        'biller_id' => [
                'OANSTOP00NAT01'
        ],
        'biller_category_name' => [
                'DTH'
        ]
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Content-Type: application/json",
    "x-api-version: <x-api-version>",
    "x-client-id: <api-key>",
    "x-client-secret: <api-key>"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://sandbox.cashfree.com/bbps/cou/v1/billers/info"

	payload := strings.NewReader("{\n  \"biller_fetch_request\": {\n    \"biller_id\": [\n      \"OANSTOP00NAT01\"\n    ],\n    \"biller_category_name\": [\n      \"DTH\"\n    ]\n  }\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("x-api-version", "<x-api-version>")
	req.Header.Add("x-client-id", "<api-key>")
	req.Header.Add("x-client-secret", "<api-key>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://sandbox.cashfree.com/bbps/cou/v1/billers/info")
  .header("x-api-version", "<x-api-version>")
  .header("x-client-id", "<api-key>")
  .header("x-client-secret", "<api-key>")
  .header("Content-Type", "application/json")
  .body("{\n  \"biller_fetch_request\": {\n    \"biller_id\": [\n      \"OANSTOP00NAT01\"\n    ],\n    \"biller_category_name\": [\n      \"DTH\"\n    ]\n  }\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://sandbox.cashfree.com/bbps/cou/v1/billers/info")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["x-api-version"] = '<x-api-version>'
request["x-client-id"] = '<api-key>'
request["x-client-secret"] = '<api-key>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"biller_fetch_request\": {\n    \"biller_id\": [\n      \"OANSTOP00NAT01\"\n    ],\n    \"biller_category_name\": [\n      \"DTH\"\n    ]\n  }\n}"

response = http.request(request)
puts response.read_body

{
  "status": "OK",
  "message": "Billers info fetched successfully",
  "data": [
    {
      "biller_id": "NETFLIX00NAT02",
      "biller_alias_name": "Netflix - Dummy",
      "biller_name": "Netflix - Dummy",
      "biller_category_name": "Subscription",
      "biller_mode": "ONLINE",
      "biller_accepts_adhoc": true,
      "biller_coverage": "IND",
      "fetch_requirement": "NOT_SUPPORTED",
      "payment_amount_exactness": "Exact",
      "support_bill_validation": "MANDATORY",
      "biller_effctv_from": "2021-01-15",
      "biller_effctv_to": "2031-12-31",
      "biller_ownership": "Private",
      "status": "ACTIVE",
      "plan_mdm_requirement": "MANDATORY",
      "biller_customer_params": [
        {
          "param_name": "Customer Mobile Number",
          "data_type": "NUMERIC",
          "optional": true,
          "min_length": 10,
          "max_length": 10,
          "regex": "^[6-9]{1}[0-9]{9}$",
          "visibility": true
        }
      ],
      "biller_payment_modes": [
        {
          "payment_mode": "UPI",
          "min_limit": 1,
          "max_limit": 1,
          "support_pending_status": "Yes"
        }
      ]
    }
  ]
}

{
  "message": "biller_fetch_request.biller_category_name[1] : is missing in the request. Value received: ",
  "code": "biller_fetch_request.biller_category_name[1]_missing",
  "type": "invalid_request_error"
}

{
  "message": "authentication Failed",
  "code": "request_failed",
  "type": "authentication_error"
}

{
  "message": "Too many requests from IP. Check headers",
  "code": "request_failed",
  "type": "rate_limit_error"
}

{
  "message": "internal Server Error",
  "code": "internal_error",
  "type": "api_error"
}