---
title: "slack: Send alerts and notifications to a Slack channel"
url: "https://axoflow.com/docs/axosyslog-core/4.28/chapter-destinations/destination-slack/"
last_modified: "2026-08-05T15:08:09+02:00"
---

> For the complete documentation index, see [llms.txt](https://axoflow.com/docs/axosyslog-core/4.28/llms.txt).

# slack: Send alerts and notifications to a Slack channel

The `slack()` destination driver sends messages to a [Slack](https://slack.com/) channel using the Slack Web API. For the list of available optional parameters, see [Slack destination options](https://axoflow.com/docs/axosyslog-core/4.28/chapter-destinations/destination-slack/reference-destination-slack/index.md).

## Prerequisites

- AxoSyslog version 3.19 or later.
- Install the `axosyslog-scl` package on [Debian/Ubuntu](https://axoflow.com/docs/axosyslog-core/4.28/install/debian-ubuntu/index.md). On [RHEL and compatible distributions](https://axoflow.com/docs/axosyslog-core/4.28/install/rhel-fedora-almalinux/index.md), the SCL files are part of the `axosyslog` base package.

  Your configuration must also contain `@include "scl.conf"`, which the default configuration file already does. If the SCL files are missing, AxoSyslog fails to start with an [`unexpected LL_IDENTIFIER` error](https://axoflow.com/docs/axosyslog-core/4.28/chapter-troubleshooting-syslog-ng/unexpected-ll-identifier/index.md).

  ```shell
  @include "scl.conf"
  ```

  The `slack()` driver is a reusable configuration snippet (SCL). For details on using or writing such configuration snippets, see [Reusing configuration blocks](https://axoflow.com/docs/axosyslog-core/4.28/chapter-configuration-file/large-configs/config-blocks/index.md). You can find its source in [scl/slack/slack.conf](https://github.com/axoflow/axosyslog/blob/main/scl/slack/slack.conf) on GitHub.
- This feature requires a separate module. Install the `axosyslog-mod-http` package on [Debian/Ubuntu](https://axoflow.com/docs/axosyslog-core/4.28/install/debian-ubuntu/index.md), or the `axosyslog-http` package on [RHEL and compatible distributions](https://axoflow.com/docs/axosyslog-core/4.28/install/rhel-fedora-almalinux/index.md). If the module isn’t installed, AxoSyslog fails to start with an [`unexpected LL_IDENTIFIER` error](https://axoflow.com/docs/axosyslog-core/4.28/chapter-troubleshooting-syslog-ng/unexpected-ll-identifier/index.md).
- Create a Slack app and a Webhook that AxoSyslog can use. For details, see the [Slack documentation](https://api.slack.com/incoming-webhooks).

## Declaration:

```shell
@include "scl.conf"
# ...

destination d_slack {
  slack(
    hook-url("https://hooks.slack.com/services/T00000000/B00000000/XXXXXXXXXXXXXXXXXXXXXXXX")
  );
};
```

The driver allows you to modify nearly every field of the HTTP request. For details, see the [Slack API documentation](https://api.slack.com/docs).

You can use the `proxy()` option to configure the HTTP driver in all HTTP-based destinations to use a specific HTTP proxy that is independent from the proxy configured for the system.

By default, the `throttle()` option is set to 1, because Slack has a 1 message/second limit on Webhooks. It can allow more message in short bursts, so you can set it to 0, if you only expect messages in a short period of time. For details, see the [Web API rate limiting in the Slack documentation](https://api.slack.com/apis/rate-limits).

## Example: Using the slack() driver

The following example sets the colors and the author of the message.

```shell
@include "scl.conf"

destination d_slack1 {
  slack(
    hook-url("https://hooks.slack.com/services/T00000000/B00000000/XXXXXXXXXXXXXXXXXXXXXXXX")
    colors("#000000,#222222,#444444,#666666,#888888,#AAAAAA,#CCCCCC,#EEEEEE")
    color-chooser(7)
    author-name("Example BOT")
    author-link("https://www.syslog-ng.com/products/open-source-log-management")
    author-icon("https://raw.githubusercontent.com/MrAnno/vscode-syslog-ng/master/images/syslog-ng-icon.png")
  );
};
```

---

[Slack destination options](https://axoflow.com/docs/axosyslog-core/4.28/chapter-destinations/destination-slack/reference-destination-slack/index.md)

Last modified August 5, 2026: [Small fixes and deduplications (99cac43a)](https://github.com/axoflow/axosyslog-core-docs/commit/99cac43a517770299b97c7ed360eb87af9fef5ab)