Slack

Receive Slack Events API and interactivity requests.

The signing secret is on your Slack app's Basic Information page. Slack sends a url_verification challenge when you register the URL; answer it from the handler.

app/api/webhooks/slack/route.ts

import { webhook, slack } from "next-webhooks";

export const POST = webhook({
  provider: slack({ secret: process.env.SLACK_SIGNING_SECRET! }),
  handler: async (event) => {
    const payload = event.payload as {
      type?: string;
      challenge?: string;
      event?: unknown;
    };
    if (payload?.type === "url_verification") {
      return Response.json({ challenge: payload.challenge });
    }
    if (payload?.type === "event_callback") {
      // payload.event has the actual event (message, reaction_added, ...)
    }
  },
});

Notes

Slack expects a response within 3 seconds, so keep the handler fast and defer heavy work
Events are deduplicated by the event_id field in the payload