Server-Side POST

Any language that can send an HTTP POST can submit to html.contact. These examples use public form endpoints with hc_pub_ keys, not private API keys.

The public form endpoints accept form data, not JSON request bodies.

These examples are for servers, terminal tests, jobs, and custom backends. Do not copy the Node fetch() pattern into browser JavaScript. For websites, use a normal <form>.

Use the public form endpoint:

https://html.contact/f/hc_pub_REPLACE

Or use the compatibility endpoint with form_key:

https://html.contact/submit

cURL

When testing with a normal website form configuration, include source headers that match an allowed domain:

curl "https://html.contact/f/hc_pub_REPLACE?format=json" \
  -H "Accept: application/json" \
  -H "Origin: https://example.com" \
  -H "Referer: https://example.com/contact" \
  --data-urlencode "name=Mara Quill" \
  --data-urlencode "email=mara@example.com" \
  --data-urlencode "subject=Quote request" \
  --data-urlencode "message=Can you send pricing?"

Node

Server-side Node example:

const body = new URLSearchParams({
  name: "Mara Quill",
  email: "mara@example.com",
  subject: "Quote request",
  message: "Can you send pricing?",
});

const response = await fetch("https://html.contact/f/hc_pub_REPLACE?format=json", {
  method: "POST",
  headers: {
    Accept: "application/json",
    "Content-Type": "application/x-www-form-urlencoded",
    Origin: "https://example.com",
    Referer: "https://example.com/contact",
  },
  body,
});

console.log(await response.json());

Python

Server-side Python example:

import requests

response = requests.post(
    "https://html.contact/f/hc_pub_REPLACE?format=json",
    headers={
        "Accept": "application/json",
        "Origin": "https://example.com",
        "Referer": "https://example.com/contact",
    },
    data={
        "name": "Mara Quill",
        "email": "mara@example.com",
        "subject": "Quote request",
        "message": "Can you send pricing?",
    },
)

print(response.json())

PHP

Server-side PHP example:

<?php
$response = file_get_contents(
    "https://html.contact/f/hc_pub_REPLACE?format=json",
    false,
    stream_context_create([
        "http" => [
            "method" => "POST",
            "header" => "Accept: application/json\r\nContent-Type: application/x-www-form-urlencoded\r\nOrigin: https://example.com\r\nReferer: https://example.com/contact\r\n",
            "content" => http_build_query([
                "name" => "Mara Quill",
                "email" => "mara@example.com",
                "subject" => "Quote request",
                "message" => "Can you send pricing?",
            ]),
        ],
    ])
);

echo $response;

Language support

There is no language lock-in. html.contact works from any runtime that can send application/x-www-form-urlencoded or multipart/form-data.

That includes Node, Python, PHP, Ruby, Go, Java, C#, Swift, Kotlin, Bash, and most serverless platforms.

Source checks

Normal browser forms should be tested from an allowlisted website domain.

Server-side posts without Origin or Referer headers require direct submissions to be enabled for that form. If direct submissions are off, expect origin_missing.

Only server code can set the example source headers shown above. Browser JavaScript cannot set Origin or Referer manually.