Fill in the incident details and watch the Slack message take shape. Copy the Block Kit JSON for your alerting tool, or a curl command that posts it to an incoming webhook.
Runs entirely in your browser — nothing you enter here is sent to a server.
An alert message has one job: let the person who sees it decide in five seconds whether to act and where to start. Plain-text alerts fail at this because everything has the same weight. Slack's Block Kit lets you give the message structure — a header that states the problem, a compact grid of facts, a short description and buttons that go straight to the runbook and the dashboard.
The builder produces that layout: a header block, a section with four fields, an optional description, an actions block with link buttons and a context line with the time. It also sets the top-level text, which Slack uses for notifications and screen readers.
"Checkout API is returning 5xx errors" beats "High error rate alert firing". Say what is broken, in the words a customer would use.
The best moment to tell someone how to respond is the moment they are paged. One button saves minutes of searching.
Current value and threshold, and the scope — which region, which customers. It tells the reader how bad it is.
Post a "Resolved" update in the same channel, so nobody keeps investigating a problem that has gone.
Create an incoming webhook in your Slack workspace, then POST the JSON to its URL — the "Copy as curl" button gives you a command to try it. Most alerting tools accept the same JSON as a custom payload template; replace the fixed values with the tool's variables for alert name, status and links. Keep the webhook URL secret: anyone who has it can post to the channel.
Slack's JSON format for structured messages. A message is a list of blocks — headers, sections, buttons, context lines — that Slack renders as a formatted layout instead of plain text.
Create an incoming webhook for a channel and POST the JSON to the webhook URL with the Content-Type application/json header. The payload works as is.
Slack shows the top-level text in notifications and uses it as a fallback where blocks cannot be displayed. Without it, the push notification would be empty.
Yes. In mrkdwn fields use <@USERID> for a user, <!subteam^ID> for a group, <!here> for the channel and :emoji_name: for emoji. Plain "@name" is shown as text and does not notify.
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