curl --request POST \
  --url https://app.lettr.com/api/campaigns \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "name": "October newsletter",
  "subject": "News for October",
  "from_email": "news@example.com",
  "from_name": "Example",
  "reply_to": "jsmith@example.com",
  "html_content": "<p>Hello {{first_name}}</p>",
  "json_content": {},
  "template_id": 123,
  "audience_config": {
    "all_contacts": true,
    "list_ids": [
      "<string>"
    ],
    "segment_ids": [
      "<string>"
    ],
    "topic_id": "<string>"
  },
  "language_overrides": {}
}
'

import requests

url = "https://app.lettr.com/api/campaigns"

payload = {
    "name": "October newsletter",
    "subject": "News for October",
    "from_email": "news@example.com",
    "from_name": "Example",
    "reply_to": "jsmith@example.com",
    "html_content": "<p>Hello {{first_name}}</p>",
    "json_content": {},
    "template_id": 123,
    "audience_config": {
        "all_contacts": True,
        "list_ids": ["<string>"],
        "segment_ids": ["<string>"],
        "topic_id": "<string>"
    },
    "language_overrides": {}
}
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({
    name: 'October newsletter',
    subject: 'News for October',
    from_email: 'news@example.com',
    from_name: 'Example',
    reply_to: 'jsmith@example.com',
    html_content: '<p>Hello {{first_name}}</p>',
    json_content: {},
    template_id: 123,
    audience_config: {
      all_contacts: true,
      list_ids: ['<string>'],
      segment_ids: ['<string>'],
      topic_id: '<string>'
    },
    language_overrides: {}
  })
};

fetch('https://app.lettr.com/api/campaigns', 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://app.lettr.com/api/campaigns",
  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([
    'name' => 'October newsletter',
    'subject' => 'News for October',
    'from_email' => 'news@example.com',
    'from_name' => 'Example',
    'reply_to' => 'jsmith@example.com',
    'html_content' => '<p>Hello {{first_name}}</p>',
    'json_content' => [
        
    ],
    'template_id' => 123,
    'audience_config' => [
        'all_contacts' => true,
        'list_ids' => [
                '<string>'
        ],
        'segment_ids' => [
                '<string>'
        ],
        'topic_id' => '<string>'
    ],
    'language_overrides' => [
        
    ]
  ]),
  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://app.lettr.com/api/campaigns"

	payload := strings.NewReader("{\n  \"name\": \"October newsletter\",\n  \"subject\": \"News for October\",\n  \"from_email\": \"news@example.com\",\n  \"from_name\": \"Example\",\n  \"reply_to\": \"jsmith@example.com\",\n  \"html_content\": \"<p>Hello {{first_name}}</p>\",\n  \"json_content\": {},\n  \"template_id\": 123,\n  \"audience_config\": {\n    \"all_contacts\": true,\n    \"list_ids\": [\n      \"<string>\"\n    ],\n    \"segment_ids\": [\n      \"<string>\"\n    ],\n    \"topic_id\": \"<string>\"\n  },\n  \"language_overrides\": {}\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://app.lettr.com/api/campaigns")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"name\": \"October newsletter\",\n  \"subject\": \"News for October\",\n  \"from_email\": \"news@example.com\",\n  \"from_name\": \"Example\",\n  \"reply_to\": \"jsmith@example.com\",\n  \"html_content\": \"<p>Hello {{first_name}}</p>\",\n  \"json_content\": {},\n  \"template_id\": 123,\n  \"audience_config\": {\n    \"all_contacts\": true,\n    \"list_ids\": [\n      \"<string>\"\n    ],\n    \"segment_ids\": [\n      \"<string>\"\n    ],\n    \"topic_id\": \"<string>\"\n  },\n  \"language_overrides\": {}\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://app.lettr.com/api/campaigns")

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  \"name\": \"October newsletter\",\n  \"subject\": \"News for October\",\n  \"from_email\": \"news@example.com\",\n  \"from_name\": \"Example\",\n  \"reply_to\": \"jsmith@example.com\",\n  \"html_content\": \"<p>Hello {{first_name}}</p>\",\n  \"json_content\": {},\n  \"template_id\": 123,\n  \"audience_config\": {\n    \"all_contacts\": true,\n    \"list_ids\": [\n      \"<string>\"\n    ],\n    \"segment_ids\": [\n      \"<string>\"\n    ],\n    \"topic_id\": \"<string>\"\n  },\n  \"language_overrides\": {}\n}"

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