curl --request POST \
  --url https://api.kit.com/v4/broadcasts \
  --header 'Content-Type: application/json' \
  --header 'X-Kit-Api-Key: <api-key>' \
  --data '
{
  "email_template_id": 2,
  "email_address": null,
  "content": "<p>Let me introduce myself</p>",
  "description": "Intro email",
  "public": true,
  "published_at": "2023-02-17T11:43:55+00:00",
  "send_at": null,
  "thumbnail_alt": null,
  "thumbnail_url": null,
  "preview_text": "Pleased to meet you!",
  "subject": "Hello!",
  "subscriber_filter": [
    {
      "all": [
        {
          "type": "segment",
          "ids": [
            18
          ]
        }
      ],
      "any": null,
      "none": null
    }
  ]
}
'

require 'uri'
require 'net/http'

url = URI("https://api.kit.com/v4/broadcasts")

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

request = Net::HTTP::Post.new(url)
request["X-Kit-Api-Key"] = '<api-key>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"email_template_id\": 2,\n  \"email_address\": null,\n  \"content\": \"<p>Let me introduce myself</p>\",\n  \"description\": \"Intro email\",\n  \"public\": true,\n  \"published_at\": \"2023-02-17T11:43:55+00:00\",\n  \"send_at\": null,\n  \"thumbnail_alt\": null,\n  \"thumbnail_url\": null,\n  \"preview_text\": \"Pleased to meet you!\",\n  \"subject\": \"Hello!\",\n  \"subscriber_filter\": [\n    {\n      \"all\": [\n        {\n          \"type\": \"segment\",\n          \"ids\": [\n            18\n          ]\n        }\n      ],\n      \"any\": null,\n      \"none\": null\n    }\n  ]\n}"

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

const options = {
  method: 'POST',
  headers: {'X-Kit-Api-Key': '<api-key>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    email_template_id: 2,
    email_address: null,
    content: '<p>Let me introduce myself</p>',
    description: 'Intro email',
    public: true,
    published_at: '2023-02-17T11:43:55+00:00',
    send_at: null,
    thumbnail_alt: null,
    thumbnail_url: null,
    preview_text: 'Pleased to meet you!',
    subject: 'Hello!',
    subscriber_filter: [{all: [{type: 'segment', ids: [18]}], any: null, none: null}]
  })
};

fetch('https://api.kit.com/v4/broadcasts', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

package main

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

func main() {

	url := "https://api.kit.com/v4/broadcasts"

	payload := strings.NewReader("{\n  \"email_template_id\": 2,\n  \"email_address\": null,\n  \"content\": \"<p>Let me introduce myself</p>\",\n  \"description\": \"Intro email\",\n  \"public\": true,\n  \"published_at\": \"2023-02-17T11:43:55+00:00\",\n  \"send_at\": null,\n  \"thumbnail_alt\": null,\n  \"thumbnail_url\": null,\n  \"preview_text\": \"Pleased to meet you!\",\n  \"subject\": \"Hello!\",\n  \"subscriber_filter\": [\n    {\n      \"all\": [\n        {\n          \"type\": \"segment\",\n          \"ids\": [\n            18\n          ]\n        }\n      ],\n      \"any\": null,\n      \"none\": null\n    }\n  ]\n}")

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

	req.Header.Add("X-Kit-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))

}

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.kit.com/v4/broadcasts",
  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([
    'email_template_id' => 2,
    'email_address' => null,
    'content' => '<p>Let me introduce myself</p>',
    'description' => 'Intro email',
    'public' => true,
    'published_at' => '2023-02-17T11:43:55+00:00',
    'send_at' => null,
    'thumbnail_alt' => null,
    'thumbnail_url' => null,
    'preview_text' => 'Pleased to meet you!',
    'subject' => 'Hello!',
    'subscriber_filter' => [
        [
                'all' => [
                                [
                                                                'type' => 'segment',
                                                                'ids' => [
                                                                                                                                18
                                                                ]
                                ]
                ],
                'any' => null,
                'none' => null
        ]
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Content-Type: application/json",
    "X-Kit-Api-Key: <api-key>"
  ],
]);

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

curl_close($curl);

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

import requests

url = "https://api.kit.com/v4/broadcasts"

payload = {
    "email_template_id": 2,
    "email_address": None,
    "content": "<p>Let me introduce myself</p>",
    "description": "Intro email",
    "public": True,
    "published_at": "2023-02-17T11:43:55+00:00",
    "send_at": None,
    "thumbnail_alt": None,
    "thumbnail_url": None,
    "preview_text": "Pleased to meet you!",
    "subject": "Hello!",
    "subscriber_filter": [
        {
            "all": [
                {
                    "type": "segment",
                    "ids": [18]
                }
            ],
            "any": None,
            "none": None
        }
    ]
}
headers = {
    "X-Kit-Api-Key": "<api-key>",
    "Content-Type": "application/json"
}

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

print(response.text)

{
  "broadcast": {
    "id": 64,
    "publication_id": 55,
    "created_at": "2023-02-17T11:43:55Z",
    "subject": "Hello!",
    "preview_text": "Pleased to meet you!",
    "description": "Intro email",
    "content": "<p>Let me introduce myself</p>",
    "public": true,
    "published_at": "2023-02-17T11:43:55Z",
    "send_at": null,
    "thumbnail_alt": null,
    "thumbnail_url": null,
    "public_url": "https://kit-greetings.kit.com/posts/",
    "email_address": "greetings@kit.dev",
    "email_template": {
      "id": 2,
      "name": "Classic"
    },
    "subscriber_filter": [
      {
        "all": [
          {
            "type": "segment",
            "ids": [
              18
            ]
          }
        ]
      }
    ],
    "status": "draft"
  }
}

{
  "errors": [
    "The access token is invalid"
  ]
}

{
  "errors": [
    "You do not have sufficient permissions to access this resource. Please contact support."
  ]
}

{
  "errors": [
    "Email template not found",
    "Only a single filter group is supported. Use one of `all`, `any`, or `none`."
  ]
}