curl --request POST \
  --url https://api.instantly.ai/api/v2/custom-tags \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "label": "Important"
}
'

import requests

url = "https://api.instantly.ai/api/v2/custom-tags"

payload = { "label": "Important" }
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({label: 'Important'})
};

fetch('https://api.instantly.ai/api/v2/custom-tags', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

HttpResponse<String> response = Unirest.post("https://api.instantly.ai/api/v2/custom-tags")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"label\": \"Important\"\n}")
  .asString();

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.instantly.ai/api/v2/custom-tags",
  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([
    'label' => 'Important'
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($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.instantly.ai/api/v2/custom-tags"

	payload := strings.NewReader("{\n  \"label\": \"Important\"\n}")

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

	req.Header.Add("Authorization", "Bearer <token>")
	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))

}

{
  "id": "019fef96-3cda-7bf8-bc21-8919fda2a0fc",
  "timestamp_created": "2026-08-11T06:50:28.442Z",
  "timestamp_updated": "2026-08-11T06:50:28.442Z",
  "organization_id": "019fef96-3cda-7bf8-bc21-891a8454fc43",
  "label": "Important",
  "description": "Used for marking important items"
}

{
  "statusCode": 400,
  "error": "Bad Request",
  "message": "body must have required property 'name'"
}

{
  "statusCode": 401,
  "error": "Unauthorized",
  "message": "Missing Authorization header"
}

{
  "statusCode": 402,
  "error": "Payment Required",
  "message": "Workspace does not have an active paid plan"
}

{
  "statusCode": 404,
  "error": "Not Found",
  "message": "Resource not found"
}

{
  "statusCode": 409,
  "error": "Conflict",
  "message": "A tag with this name already exists."
}

{
  "statusCode": 429,
  "error": "Too Many Requests",
  "message": "Rate limit exceeded"
}