How to Create a Slack Webhook URL in 4 Steps

To create a Slack webhook, make a Slack app and turn on incoming webhooks. Go to api.slack.com/apps, click Create New App, choose From scratch and pick your workspace. Open Incoming Webhooks, switch Activate Incoming Webhooks on, click Add New Webhook to Workspace, choose the channel and click Authorize. Slack shows a URL like https://hooks.slack.com/services/T000/B000/XXXX. Anything you POST to it as JSON appears in that channel.

Each URL posts to one channel. You cannot change the channel, name or icon per message; Slack's docs say those always come from the app. For a private channel you must be a member first.

We build Slack Green. Our free Markdown to Slack converter turns standard markdown into the mrkdwn a webhook message expects.

Create the webhook URL

• Create an app. Open api.slack.com/apps, click Create New App, then From scratch. Name it after what will post, such as "Deploy bot", and pick the workspace.
• Turn on incoming webhooks. In the app settings, click Incoming Webhooks in the left menu and switch Activate Incoming Webhooks to On.
• Add a webhook. Click Add New Webhook to Workspace at the bottom. Pick the channel and click Authorize. If your workspace requires admin approval for apps, the request goes to an admin first.
• Copy the URL from Webhook URLs for Your Workspace.

Test it from a terminal:

curl -X POST -H 'Content-type: application/json' \
  --data '{"text":"Hello from my webhook"}' \
  https://hooks.slack.com/services/T000/B000/XXXX

Slack answers ok with HTTP 200 and the message appears in the channel, posted by your app.

Treat the URL like a password. Slack's docs warn that it contains a secret and that Slack searches for leaked webhook URLs and revokes them. Keep it in an environment variable or a secrets store, not in a public repository.

Private channels, DMs and several channels

• • Private channel. Join the channel first. Slack only lists private channels you are in when you authorize the webhook.
• • Direct message. The channel picker also lists people. Choose yourself to get messages in your own DM, which is handy for personal alerts.
• • Several channels. Click Add New Webhook to Workspace again for each channel. Every channel gets its own URL, all under the same app.
• • Change the channel. You cannot edit it. Add a new webhook for the new channel and remove the old one under Webhook URLs for Your Workspace.

If you need to pick the channel per message, or edit and delete messages later, use a bot token and chat.postMessage instead. Webhooks cannot delete a message once it is posted.

App webhook or Workflow Builder webhook?

Slack has a second kind of webhook that needs no app. In Workflow Builder, start a workflow From a webhook. Slack gives you a URL starting with https://hooks.slack.com/triggers/, and the workflow's steps decide what to post and where.

Pick Workflow Builder when a non-developer should own the message text. Pick an app webhook when your code builds the message. Ideas for workflows are in Slack Workflow Builder examples.

Send a formatted message

A webhook accepts the same JSON as other Slack messages: text for the notification and fallback, and blocks for the layout.

{
  "text": "Deploy finished",
  "blocks": [
    {
      "type": "section",
      "text": { "type": "mrkdwn", "text": "*Deploy finished* for `web`\n<https://example.com/runs/42|Open the run>" }
    }
  ]
}

Tested curl, Python and Node.js senders, with retries for 429, are in Slack webhook curl example. Links use <url|text> in webhook messages, not [text](url). The syntax for bold, lists, mentions and the markdown block is in Slack Block Kit markdown, and a ready GitHub setup is in how to send a Slack message from GitHub Actions. To put a new line in the text, send \n; more in how to add a new line in Slack.

Webhook errors

Slack's docs say an invalid_payload should not be retried without a fix. For no_service, create a new webhook; the old URL will not come back.

FAQ

How do I get a Slack webhook URL? Create an app at api.slack.com/apps, activate Incoming Webhooks, click Add New Webhook to Workspace and choose a channel.

Can a Slack webhook post to a private channel? Yes, if you are a member of the channel when you create the webhook.

Can one webhook post to several channels? No. Create one webhook per channel under the same app.

Can a Slack webhook send a DM? Yes. Pick a person, such as yourself, in the channel picker when you add the webhook.

Is a Slack webhook free? App incoming webhooks work on every plan. Workflow Builder webhooks need a paid plan.