curl --request POST \
  --url https://attend.hackclub.com/api/v1/events/{event_id}/messages \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "message": {
    "audience": "specific_participants",
    "channels": [
      "email"
    ],
    "subject": "Your bus leaves at 9",
    "body": "<p>Meet at the front entrance.</p>",
    "participant_event_ids": [
      "3f0c1a52-1d55-4f43-9a0b-6b3b8e0f2b11",
      "8a7d2e90-5c3b-4c55-8f0e-2e9d1c4b7a66"
    ]
  }
}
'

import requests

url = "https://attend.hackclub.com/api/v1/events/{event_id}/messages"

payload = { "message": {
        "audience": "specific_participants",
        "channels": ["email"],
        "subject": "Your bus leaves at 9",
        "body": "<p>Meet at the front entrance.</p>",
        "participant_event_ids": ["3f0c1a52-1d55-4f43-9a0b-6b3b8e0f2b11", "8a7d2e90-5c3b-4c55-8f0e-2e9d1c4b7a66"]
    } }
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({
    message: {
      audience: 'specific_participants',
      channels: ['email'],
      subject: 'Your bus leaves at 9',
      body: JSON.stringify('<p>Meet at the front entrance.</p>'),
      participant_event_ids: ['3f0c1a52-1d55-4f43-9a0b-6b3b8e0f2b11', '8a7d2e90-5c3b-4c55-8f0e-2e9d1c4b7a66']
    }
  })
};

fetch('https://attend.hackclub.com/api/v1/events/{event_id}/messages', 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://attend.hackclub.com/api/v1/events/{event_id}/messages",
  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([
    'message' => [
        'audience' => 'specific_participants',
        'channels' => [
                'email'
        ],
        'subject' => 'Your bus leaves at 9',
        'body' => '<p>Meet at the front entrance.</p>',
        'participant_event_ids' => [
                '3f0c1a52-1d55-4f43-9a0b-6b3b8e0f2b11',
                '8a7d2e90-5c3b-4c55-8f0e-2e9d1c4b7a66'
        ]
    ]
  ]),
  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://attend.hackclub.com/api/v1/events/{event_id}/messages"

	payload := strings.NewReader("{\n  \"message\": {\n    \"audience\": \"specific_participants\",\n    \"channels\": [\n      \"email\"\n    ],\n    \"subject\": \"Your bus leaves at 9\",\n    \"body\": \"<p>Meet at the front entrance.</p>\",\n    \"participant_event_ids\": [\n      \"3f0c1a52-1d55-4f43-9a0b-6b3b8e0f2b11\",\n      \"8a7d2e90-5c3b-4c55-8f0e-2e9d1c4b7a66\"\n    ]\n  }\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))

}

HttpResponse<String> response = Unirest.post("https://attend.hackclub.com/api/v1/events/{event_id}/messages")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"message\": {\n    \"audience\": \"specific_participants\",\n    \"channels\": [\n      \"email\"\n    ],\n    \"subject\": \"Your bus leaves at 9\",\n    \"body\": \"<p>Meet at the front entrance.</p>\",\n    \"participant_event_ids\": [\n      \"3f0c1a52-1d55-4f43-9a0b-6b3b8e0f2b11\",\n      \"8a7d2e90-5c3b-4c55-8f0e-2e9d1c4b7a66\"\n    ]\n  }\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://attend.hackclub.com/api/v1/events/{event_id}/messages")

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

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"message\": {\n    \"audience\": \"specific_participants\",\n    \"channels\": [\n      \"email\"\n    ],\n    \"subject\": \"Your bus leaves at 9\",\n    \"body\": \"<p>Meet at the front entrance.</p>\",\n    \"participant_event_ids\": [\n      \"3f0c1a52-1d55-4f43-9a0b-6b3b8e0f2b11\",\n      \"8a7d2e90-5c3b-4c55-8f0e-2e9d1c4b7a66\"\n    ]\n  }\n}"

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

{
  "message": {
    "id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
    "subject": "<string>",
    "status": "draft",
    "audience": "confirmed_attendees",
    "audience_label": "Confirmed Attendees",
    "channels": [
      "slack"
    ],
    "recipient_count": 123,
    "sent_count": 123,
    "failed_count": 123,
    "scheduled_at": "2023-11-07T05:31:56Z",
    "sent_at": "2023-11-07T05:31:56Z",
    "created_at": "2023-11-07T05:31:56Z",
    "sent_by": "<string>",
    "preview_text": "<string>",
    "body": "<string>",
    "body_html": "<string>",
    "participant_event_ids": [
      "3c90c3cc-0d44-4b50-8888-8dd25736052a"
    ],
    "group_ids": [
      "3c90c3cc-0d44-4b50-8888-8dd25736052a"
    ],
    "opened_count": 123,
    "pending_count": 123,
    "new_recipient_count": 123,
    "recipients": [
      {
        "id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
        "name": "<string>",
        "kind": "attendee",
        "catch_up": true,
        "deliveries": [
          {
            "id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
            "channel": "slack",
            "status": "pending",
            "recipient_identifier": "<string>",
            "error_message": "<string>",
            "delivered_at": "2023-11-07T05:31:56Z",
            "read_at": "2023-11-07T05:31:56Z"
          }
        ]
      }
    ],
    "permissions": {
      "edit": true,
      "send_now": true,
      "destroy": true,
      "cancel": true,
      "retry_failed": true,
      "send_to_new_recipients": true
    }
  }
}

{
  "error": "Unauthorized"
}

{
  "error": "Unauthorized"
}

{
  "error": "Unauthorized"
}

{
  "error": "Category can't be blank",
  "errors": [
    "Category can't be blank"
  ]
}