curl --request POST \
  --url https://api.callkaro.ai/contact/update \
  --header 'Content-Type: application/json' \
  --header 'X-API-KEY: <api-key>' \
  --data '
{
  "to_number": "+919876543210",
  "attributes": [
    {
      "key": "city",
      "value": "Mumbai"
    },
    {
      "key": "first_name",
      "value": "Rahul K",
      "replace": false
    }
  ]
}
'

import requests

url = "https://api.callkaro.ai/contact/update"

payload = {
    "to_number": "+919876543210",
    "attributes": [
        {
            "key": "city",
            "value": "Mumbai"
        },
        {
            "key": "first_name",
            "value": "Rahul K",
            "replace": False
        }
    ]
}
headers = {
    "X-API-KEY": "<api-key>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {'X-API-KEY': '<api-key>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    to_number: '+919876543210',
    attributes: [
      {key: 'city', value: 'Mumbai'},
      {key: 'first_name', value: 'Rahul K', replace: false}
    ]
  })
};

fetch('https://api.callkaro.ai/contact/update', 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://api.callkaro.ai/contact/update",
  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([
    'to_number' => '+919876543210',
    'attributes' => [
        [
                'key' => 'city',
                'value' => 'Mumbai'
        ],
        [
                'key' => 'first_name',
                'value' => 'Rahul K',
                'replace' => false
        ]
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Content-Type: application/json",
    "X-API-KEY: <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://api.callkaro.ai/contact/update"

	payload := strings.NewReader("{\n  \"to_number\": \"+919876543210\",\n  \"attributes\": [\n    {\n      \"key\": \"city\",\n      \"value\": \"Mumbai\"\n    },\n    {\n      \"key\": \"first_name\",\n      \"value\": \"Rahul K\",\n      \"replace\": false\n    }\n  ]\n}")

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

	req.Header.Add("X-API-KEY", "<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://api.callkaro.ai/contact/update")
  .header("X-API-KEY", "<api-key>")
  .header("Content-Type", "application/json")
  .body("{\n  \"to_number\": \"+919876543210\",\n  \"attributes\": [\n    {\n      \"key\": \"city\",\n      \"value\": \"Mumbai\"\n    },\n    {\n      \"key\": \"first_name\",\n      \"value\": \"Rahul K\",\n      \"replace\": false\n    }\n  ]\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.callkaro.ai/contact/update")

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

request = Net::HTTP::Post.new(url)
request["X-API-KEY"] = '<api-key>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"to_number\": \"+919876543210\",\n  \"attributes\": [\n    {\n      \"key\": \"city\",\n      \"value\": \"Mumbai\"\n    },\n    {\n      \"key\": \"first_name\",\n      \"value\": \"Rahul K\",\n      \"replace\": false\n    }\n  ]\n}"

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

{
  "status": "done",
  "message": "Contact updated",
  "contact": {
    "to_number": "919876543210",
    "channels": [],
    "attributes": {
      "first_name": "Rahul",
      "city": "Mumbai"
    },
    "created_at": "2026-10-27 11:42:05.118",
    "updated_at": "2026-10-27 12:03:51.402",
    "last_message_at": null
  },
  "attributes": {
    "updated": [
      "city"
    ],
    "kept_existing": [
      "first_name"
    ],
    "ignored": [],
    "invalid": []
  }
}

{
  "status": "error",
  "message": "attributes must be a list of { key, value, replace }"
}

{
  "status": "error",
  "message": "Invalid API key"
}

{
  "status": "error",
  "message": "Account is inactive"
}

{
  "status": "error",
  "message": "Contact not found"
}