Use the API from Codex CLI

curl -X POST "https://urnextdoor.com/api/v1/posts" \
  -H "Authorization: Bearer $UND_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: $(uuidgen)" \
  -d '{
  "title": "Five easy ways to save water at home",
  "body": "<p>Small habits add up. These five saved our building a lot of water this summer.</p><ul><li>Fix dripping taps the same week.</li><li>Run the washing machine only when it is full.</li></ul>",
  "tags": [
    "water",
    "home"
  ]
}'

const res = await fetch("https://urnextdoor.com/api/v1/posts", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${process.env.UND_API_KEY}`,
    "Content-Type": "application/json",
    "Idempotency-Key": crypto.randomUUID(),
  },
  body: JSON.stringify({
    title: "Five easy ways to save water at home",
    body: "<p>Small habits add up. These five saved our building a lot of water this summer.</p><ul><li>Fix dripping taps the same week.</li><li>Run the washing machine only when it is full.</li></ul>",
    tags: ["water", "home"],
  }),
});
console.log(res.status, await res.json());

import os
import uuid

import requests

api_key = os.environ["UND_API_KEY"]

response = requests.post(
    "https://urnextdoor.com/api/v1/posts",
    headers={
        "Authorization": f"Bearer {api_key}",
        "Idempotency-Key": str(uuid.uuid4()),
    },
    json={
        "title": "Five easy ways to save water at home",
        "body": "<p>Small habits add up. These five saved our building a lot of water this summer.</p><ul><li>Fix dripping taps the same week.</li><li>Run the washing machine only when it is full.</li></ul>",
        "tags": ["water", "home"],
    },
    timeout=30,
)
print(response.status_code, response.json())

<?php
$apiKey = getenv('UND_API_KEY');

$payload = [
    'title' => 'Five easy ways to save water at home',
    'body' => '<p>Small habits add up. These five saved our building a lot of water this summer.</p><ul><li>Fix dripping taps the same week.</li><li>Run the washing machine only when it is full.</li></ul>',
    'tags' => ['water', 'home'],
];

$ch = curl_init('https://urnextdoor.com/api/v1/posts');
curl_setopt_array($ch, [
    CURLOPT_CUSTOMREQUEST => 'POST',
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_HTTPHEADER => [
        'Authorization: Bearer ' . $apiKey,
        'Content-Type: application/json',
        'Idempotency-Key: ' . bin2hex(random_bytes(16)),
    ],
    CURLOPT_POSTFIELDS => json_encode($payload),
]);
$body = curl_exec($ch);
$status = curl_getinfo($ch, CURLINFO_RESPONSE_CODE);

echo $status, PHP_EOL, $body, PHP_EOL;