---
title: "Slack developer reference"
url: "https://kestrelwp.com/docs/slack-developer-reference/"
description: "Filters for changing what each Slack for WooCommerce notification says."
published: "2026-10-06T20:27:03+00:00"
modified: "2026-10-06T20:27:03+00:00"
---

Slack for WooCommerce lets developers change what each notification says with WordPress filters. Add them in a custom plugin or your theme’s `functions.php`. These filters apply to the settings screen under **WooCommerce » Slack**; stores still on the 1.x connection run older code (see the note at the end).

Customizations aren’t covered by support. If you need help with code, work with a WordPress developer.

## Message filters

Each event’s message passes through a filter after its merge tags are filled in. The value is the message text in Slack’s formatting, so links use `<url|text>`.

| Event | Filter | Arguments |
|---|---|---|
| New order | `wcslack_new_order_message` | `$message`, `$order_id` |
| Order update | `wcslack_order_update_message` | `$message`, `$order_id` |
| Refund | `wcslack_refund_message` | `$message`, `$order_id` |
| Subscription renewal | `wcslack_sub_renew_new_message` | `$message`, `$order_id` |
| Back order | `wcslack_back_order_message` | `$message` |
| Low stock | `wcslack_low_stock_message` | `$message` |
| Out of stock | `wcslack_out_stock_message` | `$message` |
| New review | `wcslack_new_review_message` | `$message` |
| New customer | `wcslack_new_customer_message` | `$message` |
| New post | `wcslack_new_post_message` | `$message` |

For example, to add the payment method to every new order message:

```
add_filter( 'wcslack_new_order_message', function( $message, $order_id ) {
	$order = wc_get_order( $order_id );

	return $order ? $message . ' (' . $order->get_payment_method_title() . ')' : $message;
}, 10, 2 );
```

## Details filters

When **Extended** is on, the details block below the message is built from a list of fields. Each field is an array with `title`, an optional `value`, and `short` (`true` puts two fields side by side). The filters run before the line items and totals are added.

| Event | Filter | Arguments |
|---|---|---|
| New order | `wcslack_new_order_attachment` | `$fields`, `$order_id`, `$order` |
| Order update | `wcslack_order_update_attachment` | `$fields`, `$order_id`, `$order` |
| Refund | `wcslack_refund_attachment` | `$fields`, `$refund_id`, `$refund` |
| Subscription renewal | `wcslack_sub_renew_new_attachment` | `$fields`, `$order_id`, `$order` |
| New review | `wcslack_new_review_attachment` | `$fields` |
| New post | `wcslack_new_post_attachment` | `$fields` |

## Value filters

These change a single value before it goes into the message’s tags.

| Filter | Value |
|---|---|
| `wcslack_new_review_reviewer_name` | The reviewer’s name |
| `wcslack_new_review_product_name` | The reviewed product’s name |
| `wcslack_new_review_content` | The review text |
| `wcslack_new_review_rating_star` | The emoji repeated once per star, `:star:` by default |
| `wcslack_new_review_url` | The link to the review |
| `wcslack_new_customer_name` | The customer’s display name |
| `wcslack_new_customer_url` | The link to the customer’s profile in your admin |
| `wcslack_new_post_title` | The post title |
| `wcslack_new_post_content` | The post content, with HTML removed |
| `wcslack_new_post_author` | The author’s display name |
| `wcslack_new_post_url` | The post’s address |

## Other filters

### wcslack\_message\_username

Filters the sender name for every message, including the test notification. It receives the **Sender name** setting; return an empty string to use the Slack app’s own name.

### wcslack\_post\_publish\_types

The post types that send **New post**, `[ 'post', 'page' ]` by default. To include products:

```
add_filter( 'wcslack_post_publish_types', function( $types ) {
	$types[] = 'product';

	return $types;
} );
```

## Stores still on the 1.x connection

Until a store clicks **Switch to the new experience**, it runs the 1.x code, which also has `wcslack_*_prefix` filters for each message’s opening text. The settings screen in version 2.0.0 and later doesn’t use those filters, so move any prefix change into the event’s **Message** field or a message filter when you switch.

## Keep learning

- [Get started with Slack](/docs/get-started-with-slack/) (settings, events and merge tags)
- [Upgrade from version 1.x](/docs/get-started-with-slack/#upgrade-from-version-1-x)