Message formats 

Plain text and mrkdwn 

use Lex\Notifications\Slack\Message\SlackMessage;

$message = SlackMessage::text(
    ':white_check_mark: *Deployment complete*' . "\n" .
    'The website is now online.'
);

Slack interprets *bold* and other Slack formatting in supported text surfaces. It is not the same syntax as arbitrary Markdown.

Block Kit Builder JSON 

Copy the message JSON from Slack's Block Kit Builder:

$json = <<<'JSON'
{
  "blocks": [
    {
      "type": "header",
      "text": {"type": "plain_text", "text": "TYPO3 alert"}
    },
    {
      "type": "section",
      "text": {"type": "mrkdwn", "text": "*Status:* Needs attention"}
    }
  ]
}
JSON;

$message = SlackMessage::fromJson($json)
    ->withText('TYPO3 alert: Needs attention');

A bare JSON array of blocks is accepted too. Raw blocks are passed through without being converted into the library's PHP objects, so newer Slack block types can be used if the Slack endpoint supports them. The extension validates the payload structure, not every Slack-specific nested block property; Slack can still reject invalid block contents.

Native Block Kit PHP objects 

The package depends on slack-php/slack-block-kit:

use SlackPhp\BlockKit\Kit;
use Lex\Notifications\Slack\Message\SlackMessage;

$kit = Kit::message(blocks: [
    Kit::section('*TYPO3 alert*'),
    Kit::divider(),
]);

$message = SlackMessage::fromBlockKit($kit)
    ->withText('TYPO3 alert');

fromBlockKit() calls the library's validate() and toArray(). Only supported message content fields are taken from the library's serialized surface.

Legacy attachments 

$message = SlackMessage::text('Production alert')
    ->withAttachments([
        [
            'fallback' => 'Production issue detected',
            'color' => '#D92D20',
            'title' => 'Production alert',
            'text' => 'Investigate the TYPO3 instance.',
            'fields' => [
                [
                    'title' => 'Environment',
                    'value' => 'Production',
                    'short' => true,
                ],
            ],
        ],
    ]);

Legacy attachments remain supported for existing integrations. Prefer Block Kit for new layouts. text, blocks and attachments may be present together in the same payload.

PHP arrays 

$message = SlackMessage::fromArray([
    'text' => 'Monitoring update',
    'blocks' => [
        [
            'type' => 'section',
            'text' => ['type' => 'mrkdwn', 'text' => '*All good*'],
        ],
    ],
]);

Thread replies 

$message = SlackMessage::text('Deployment follow-up')
    ->inThread('1729000000.123456')
    ->withoutUnfurling();

// Optionally request broadcast to the channel (subject to Slack rules).
$broadcast = SlackMessage::text('Important follow-up')
    ->inThread('1729000000.123456', true);

The thread timestamp must match digits.digits. Whether a thread operation is available through a selected transport is determined by Slack; for workflows that require message identifiers in the response, use the Web API directly through the service-level transport rather than assuming a notification channel's send() returns one.

Accessibility 

For Block Kit notifications, provide a meaningful top-level text fallback using withText(). It benefits screen readers and notification previews. Avoid embedding critical information only in visual decorations.

Accepted top-level properties 

The value object currently permits text, blocks, attachments, thread_ts, reply_broadcast, unfurl_links, unfurl_media, mrkdwn, parse, metadata, and link_names. channel and token are rejected. Arrays of blocks and attachments must be nonempty lists of nonempty objects.