Posthog Webhooks Events

set -euo pipefail
# Create a webhook destination that fires on specific events
curl -X POST "https://us.posthog.com/api/projects/$POSTHOG_PROJECT_ID/pipeline_destinations/" \
  -H "Authorization: Bearer $POSTHOG_PERSONAL_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Signup Notifications",
    "description": "Send webhook when user signs up",
    "config": {
      "url": "https://your-app.com/webhooks/posthog",
      "method": "POST",
      "headers": {
        "X-Webhook-Secret": "your-webhook-secret"
      },
      "body": {
        "event": "{event}",
        "distinct_id": "{distinct_id}",
        "person": "{person}",
        "properties": "{properties}",
        "timestamp": "{timestamp}"
      }
    },
    "filters": {
      "events": [
        {"id": "user_signed_up", "type": "events"},
        {"id": "subscription_started", "type": "events"}
      ]
    }
  }'

// api/webhooks/posthog.ts
import { NextResponse } from 'next/server';
import crypto from 'crypto';

const WEBHOOK_SECRET = process.env.POSTHOG_WEBHOOK_SECRET!;

// Verify webhook authenticity
function verifySignature(payload: string, signature: string): boolean {
  const expected = crypto.createHmac('sha256', WEBHOOK_SECRET)
    .update(payload)
    .digest('hex');
  return crypto.timingSafeEqual(Buffer.from(signature), Buffer.from(expected));
}

interface PostHogWebhookPayload {
  event: string;
  distinct_id: string;
  properties: Record<string, any>;
  person: {
    properties: Record<string, any>;
  };
  timestamp: string;
}

export async function POST(request: Request) {
  const body = await request.text();
  const signature = request.headers.get('x-webhook-secret') || '';

  // Verify webhook is from PostHog
  if (WEBHOOK_SECRET && signature !== WEBHOOK_SECRET) {
    return NextResponse.json({ error: 'Invalid signature' }, { status: 401 });
  }

  const payload: PostHogWebhookPayload = JSON.parse(body);

  // Route to handlers based on event type
  switch (payload.event) {
    case 'user_signed_up':
      await onUserSignup(payload);
      break;
    case 'subscription_started':
      await onSubscriptionStarted(payload);
      break;
    case 'subscription_canceled':
      await onSubscriptionCanceled(payload);
      break;
    default:
      console.log(`Unhandled PostHog event: ${payload.event}`);
  }

  return NextResponse.json({ received: true });
}

async function onUserSignup(payload: PostHogWebhookPayload) {
  const { distinct_id, properties, person } = payload;
  console.log(`New signup: ${distinct_id}`);

  // Sync to CRM
  await fetch('https://api.hubspot.com/contacts/v1/contact/', {
    method: 'POST',
    headers: { Authorization: `Bearer ${process.env.HUBSPOT_KEY}` },
    body: JSON.stringify({
      properties: [
        { property: 'email', value: person.properties.email },
        { property: 'posthog_id', value: distinct_id },
      ],
    }),
  });

  // Notify Slack
  await fetch(process.env.SLACK_WEBHOOK_URL!, {
    method: 'POST',
    body: JSON.stringify({
      text: `New signup: ${person.properties.email || distinct_id} (${properties.source || 'unknown'})`,
    }),
  });
}

async function onSubscriptionStarted(payload: PostHogWebhookPayload) {
  console.log(`New subscription: ${payload.distinct_id}, plan: ${payload.properties.plan}`);
}

async function onSubscriptionCanceled(payload: PostHogWebhookPayload) {
  console.log(`Cancellation: ${payload.distinct_id}`);
}

set -euo pipefail
# List recent events by type
curl "https://us.posthog.com/api/projects/$POSTHOG_PROJECT_ID/events/?event=user_signed_up&limit=10&orderBy=-timestamp" \
  -H "Authorization: Bearer $POSTHOG_PERSONAL_API_KEY" | \
  jq '.results[] | {
    distinct_id,
    event,
    timestamp,
    properties: (.properties | {source, plan, referrer: ."$referrer"})
  }'

# Get events for a specific person
curl "https://us.posthog.com/api/projects/$POSTHOG_PROJECT_ID/events/?distinct_id=user-123&limit=20" \
  -H "Authorization: Bearer $POSTHOG_PERSONAL_API_KEY" | \
  jq '.results[] | {event, timestamp}'

// Complex event analysis with HogQL (PostHog's SQL dialect)
async function queryPostHog(hogql: string) {
  const response = await fetch(
    `https://us.posthog.com/api/projects/${process.env.POSTHOG_PROJECT_ID}/query/`,
    {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
        Authorization: `Bearer ${process.env.POSTHOG_PERSONAL_API_KEY}`,
      },
      body: JSON.stringify({
        query: { kind: 'HogQLQuery', query: hogql },
      }),
    }
  );
  return response.json();
}

// Example: Signup funnel analysis
const funnelData = await queryPostHog(`
  SELECT
    properties.$referrer AS referrer,
    count() AS signups,
    uniq(distinct_id) AS unique_users
  FROM events
  WHERE event = 'user_signed_up'
    AND timestamp > now() - interval 30 day
  GROUP BY referrer
  ORDER BY signups DESC
  LIMIT 20
`);

// Example: Feature adoption by plan
const adoptionData = await queryPostHog(`
  SELECT
    person.properties.plan AS plan,
    properties.feature_name AS feature,
    count() AS usage_count,
    uniq(distinct_id) AS unique_users
  FROM events
  WHERE event = 'feature_used'
    AND timestamp > now() - interval 7 day
  GROUP BY plan, feature
  ORDER BY usage_count DESC
  LIMIT 50
`);