Send handoffs to Slack

When a visitor asks to talk to a person, post it to a Slack channel within seconds, with the page they were on and a link to the conversation. You need: a Slack incoming webhook URL for the channel, and somewhere to run a small HTTPS function (a serverless function, a container or an existing server).

server.mjs

import crypto from "node:crypto";
import http from "node:http";

const DARWIN_SECRET = process.env.DARWIN_WEBHOOK_SECRET; // whsec_... from Integrations → API
const SLACK_URL = process.env.SLACK_WEBHOOK_URL;
const seen = new Set(); // use a database or cache in production

function verify(headers, body) {
  const id = headers["webhook-id"], ts = headers["webhook-timestamp"];
  if (!id || !ts || Math.abs(Date.now() / 1000 - Number(ts)) > 300) return false;
  const key = Buffer.from(DARWIN_SECRET.replace(/^whsec_/, ""), "base64");
  const expected = crypto.createHmac("sha256", key).update(`${id}.${ts}.${body}`).digest("base64");
  return (headers["webhook-signature"] || "").split(" ").some((entry) => {
    const sig = entry.split(",")[1] || "";
    return sig.length === expected.length && crypto.timingSafeEqual(Buffer.from(sig), Buffer.from(expected));
  });
}

http
  .createServer((req, res) => {
    let body = "";
    req.on("data", (chunk) => (body += chunk));
    req.on("end", async () => {
      if (req.method !== "POST" || !verify(req.headers, body)) return res.writeHead(400).end();
      res.writeHead(200).end(); // answer Darwin first
      const event = JSON.parse(body);
      if (event.type !== "handoff.requested" || seen.has(event.id)) return;
      seen.add(event.id);
      const c = event.data.object;
      if (!c) return;
      const who = [c.lead.first_name, c.lead.last_name].filter(Boolean).join(" ") || c.lead.email || "A visitor";
      await fetch(SLACK_URL, {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({
          text: `:raising_hand: ${who} asked for a person on ${c.page_path ?? "your site"}\n>${c.handoff?.reason ?? c.preview ?? ""}\n<https://app.meetdarwin.ai/admin/conversations|Open Conversations in Darwin>`,
        }),
      });
    });
  })
  .listen(process.env.PORT || 3000);

Deploy the function

Deploy it so it is reachable at an HTTPS address, for example https://hooks.example.com/darwin. Set SLACK_WEBHOOK_URL now; you’ll get DARWIN_WEBHOOK_SECRET in the next step.

Add the endpoint in Darwin

In Integrations → API → Webhooks, select Add endpoint, paste the address, choose only handoff.requested, and select Add endpoint. Copy the signing secret into DARWIN_WEBHOOK_SECRET and redeploy.

Test it

Select Send test event in the endpoint’s menu. Darwin should report a 200. The test event’s type is webhook.test, so nothing is posted to Slack.It worked if, after someone asks the chat on your live site to talk to a person, a message appears in the channel within a few seconds.

The same pattern sends meeting.booked to a sales channel or lead.captured to an SDR queue: subscribe to the type and read data.object. See Webhooks for every payload.

Get started

Guides

Send handoffs to Slack