Private Messages API

Use com_messages for administrator private messages between eligible Joomla users.

See the introduction for authentication, request formats and error handling.

Routes

Paths are relative to /api/index.php. Enable the corresponding Web Services plugin.

Methods	Path	Controller tasks
GET, POST	/v1/messages	messages.displayList, messages.add
GET, PATCH, DELETE	/v1/messages/{id}	messages.displayItem, messages.edit, messages.delete

Collection GET lists records; item GET reads one; POST creates; PATCH updates; DELETE removes an eligible record. Some records must first be trashed. Consult individual operation responses for exceptions.

Forms and data

Relevant forms and extension parameter manifests are:

• Message form (com_messages)

Joomla selects additional parameter fields according to the extension, client or field type. The OpenAPI specification includes these core parameter variants.

Field	JSON type or role	Meaning
user_id_to	user ID	Required eligible recipient ID, not an email address.
subject, message	string	Required subject and body.
user_id_from	response user ID	Sender determined by the authenticated user.
date_time, state	response fields	Message time and read/status information.

The administrator model applies recipient eligibility and messaging settings. These records are separate from contact messages and arbitrary outbound emails. Responses use data.id as the identifier even though the table uses message_id. Avoid automatically retrying POST after a timeout because the message may already have been sent.

Write a flat JSON object with these form fields. Do not wrap it in JSON:API data.attributes. Read-only response attributes are not a write template.

Backend server-side requests

Replace recipient ID 42 with an eligible administrator user accepting private messages. Running this sends a private message.

Joomla HTTPFactory

Use this request in a Joomla component, plugin or console command. Set the API URL, token and record values for the target site. Keep the token in your integration's secret store. HTTP and JSON errors throw exceptions for the calling extension to handle.

<?php
declare(strict_types=1);

use Joomla\Http\HttpFactory;
use Joomla\Uri\Uri;

$siteUrl = 'https://example.org';
$token = 'REPLACE_WITH_YOUR_API_TOKEN';
$headers = [
    'Accept' => 'application/vnd.api+json',
    'Content-Type' => 'application/json',
    'X-Joomla-Token' => $token,
];

$payload = [
    'user_id_to' => '42',
    'subject' => 'API example',
    'message' => 'This is a Joomla administrator private message.',
];

$uri = (new Uri($siteUrl))
    ->setPath('/api/index.php/v1/messages');
$http = (new HttpFactory())->getHttp(['follow_location' => false]);
$response = $http->post(
    $uri,
    json_encode($payload, JSON_THROW_ON_ERROR), $headers,
    30
);

$status = $response->getStatusCode();
$body = (string) $response->getBody();

if ($status < 200 || $status >= 300) {
    throw new \RuntimeException('HTTP ' . $status . ': ' . $body);
}

$document = json_decode($body, true, 512, JSON_THROW_ON_ERROR);

if (!empty($document['errors'])) {
    throw new \RuntimeException(json_encode($document['errors'], JSON_THROW_ON_ERROR));
}

if (isset($document['success']) && $document['success'] === false) {
    throw new \RuntimeException('The API action reported failure.');
}

echo json_encode($document, JSON_PRETTY_PRINT | JSON_THROW_ON_ERROR), PHP_EOL;

curl

This complete POSIX shell example requires curl 7.76 or later. On Windows, use a compatible shell such as Git Bash or WSL.

API_BASE='https://example.org/api/index.php/v1'
TOKEN='REPLACE_WITH_YOUR_API_TOKEN'

curl --silent --show-error --fail-with-body --include --globoff \
  --request POST \
  --url "$API_BASE/messages" \
  --header 'Accept: application/vnd.api+json' \
  --header 'X-Joomla-Token: '"$TOKEN" \
  --header 'Content-Type: application/json' \
  --data-binary @- <<'JSON'
{
  "user_id_to": "42",
  "subject": "API example",
  "message": "This is a Joomla administrator private message."
}
JSON

Server-side successful response

HTTP 200 OK, with Content-Type: application/vnd.api+json. The response excerpt below shows the resource structure. Responses can also contain relationships, links and metadata. IDs and values depend on the site.

{
  "data": {
    "type": "messages",
    "id": "42",
    "attributes": {
      "user_id_to": 42,
      "subject": "API example",
      "message": "This is a Joomla administrator private message."
    }
  }
}

Read GET /messages/{id} using the returned ID and an account allowed to access it.

Frontend browser requests

These examples read private messages visible to the API user with GET /messages. Calling the API from the browser still uses administrator models and ACL. Follow the browser setup and authentication guidance, including loading Joomla's core script for Joomla.request. Replace the site origin and API path, then enter the signed-in operator's personal API token when prompted. Keep shared integration tokens on the server.

Joomla.request

(async () => {
    const token = window.prompt('Enter your personal Joomla API token');

    if (!token) {
        throw new Error('An API token is required.');
    }

    const url = new URL('https://example.org');
    url.pathname = '/api/index.php/v1/messages';
    url.search = new URLSearchParams({
        "page[offset]": "0",
        "page[limit]": "20"
    }).toString();

    let xhr;

    try {
        xhr = await Joomla.request({
            url: url.toString(),
            method: 'GET',
            headers: {
                Accept: 'application/vnd.api+json',
                'X-Joomla-Token': token,
            },
            promise: true,
            onBefore(request) {
                request.timeout = 30000;
            },
        });
    } catch (error) {
        // Joomla.request rejects statuses other than 200, including 204.
        if (!(error instanceof XMLHttpRequest)) {
            throw error;
        }

        xhr = error;
    }

    if (xhr.status < 200 || xhr.status >= 300) {
        throw new Error(`HTTP ${xhr.status}: ${xhr.responseText || xhr.statusText}`);
    }

    const text = xhr.responseText;

    const document = text.trim() ? JSON.parse(text) : null;

    if (document?.errors && Object.keys(document.errors).length > 0) {
        throw new Error(JSON.stringify(document.errors));
    }

    if (document?.success === false) {
        throw new Error(document.message || 'The API action reported failure.');
    }

    console.log(document);
    return document;
})();

Native fetch()

(async () => {
    const token = window.prompt('Enter your personal Joomla API token');

    if (!token) {
        throw new Error('An API token is required.');
    }

    const url = new URL('https://example.org');
    url.pathname = '/api/index.php/v1/messages';
    url.search = new URLSearchParams({
        "page[offset]": "0",
        "page[limit]": "20"
    }).toString();

    const controller = new AbortController();
    const timeout = window.setTimeout(() => controller.abort(), 30000);
    let response;
    let text;

    try {
        response = await fetch(url, {
            method: 'GET',
            headers: {
                Accept: 'application/vnd.api+json',
                'X-Joomla-Token': token,
            },
            credentials: 'omit',
            redirect: 'error',
            signal: controller.signal,
        });
        text = await response.text();
    } finally {
        window.clearTimeout(timeout);
    }

    if (!response.ok) {
        throw new Error(`HTTP ${response.status}: ${text || response.statusText}`);
    }

    const document = text.trim() ? JSON.parse(text) : null;

    if (document?.errors && Object.keys(document.errors).length > 0) {
        throw new Error(JSON.stringify(document.errors));
    }

    if (document?.success === false) {
        throw new Error(document.message || 'The API action reported failure.');
    }

    console.log(document);
    return document;
})();

Both examples check the HTTP status and API error fields. An empty successful body produces null; a JSON collection has an array in data.

Browser successful response

HTTP 200 OK returns a collection such as:

{
  "data": [
    {
      "type": "messages",
      "id": "42",
      "attributes": {
        "user_id_to": 42,
        "subject": "API example",
        "message": "This is a Joomla administrator private message."
      }
    }
  ]
}

This collection excerpt omits other attributes, relationships, links and metadata. An empty result has "data": [].

Errors

These responses apply to server-side and browser clients. Check both HTTP status and response body. Wording depends on the site language, plugins and server configuration. The following examples show possible error responses.

HTTP status	Possible cause
401	Authentication is absent or invalid, or API login is not allowed.
400	Recipient, subject or message validation fails, or messaging is unavailable.
403	The user cannot access messaging or this message.
404	The message does not exist.

Form validation can produce HTTP 400 Bad Request:

{
  "errors": [
    {
      "title": "Invalid field: Subject"
    }
  ]
}

Authentication failure can produce HTTP 401 Unauthorized:

{
  "errors": [
    {
      "title": "Forbidden"
    }
  ]
}

After an interrupted or failed write, read the resource before retrying. Saving may have occurred before a later error.

References

• OpenAPI reference
• Complete OpenAPI specification, including com_messages schemas
• Joomla Web Services Collection for Postman