Billing Event Streaming

Pipe billing events from your payment processor into PostHog so you can correlate revenue data with product behavior. This enables analysis like "users who hit usage tier X churn at Y% within 30 days" or "ARPU by activation cohort."

Architecture

Stripe emits webhook events. An n8n workflow receives them and forwards them to PostHog as custom events with billing properties attached to the user.

Step 1: Configure Stripe Webhook

curl https://api.stripe.com/v1/webhook_endpoints \
  -u "$STRIPE_SECRET_KEY:" \
  -d "url=https://your-n8n.example.com/webhook/stripe-billing" \
  -d "enabled_events[]=customer.subscription.created" \
  -d "enabled_events[]=customer.subscription.updated" \
  -d "enabled_events[]=customer.subscription.deleted" \
  -d "enabled_events[]=invoice.paid" \
  -d "enabled_events[]=invoice.payment_failed" \
  -d "enabled_events[]=customer.subscription.trial_will_end" \
  -d "enabled_events[]=billing.meter.usage_reported"

Store the webhook_secret (starts with whsec_) for signature verification.

Step 2: n8n Webhook Receiver

Build an n8n workflow:

1. Trigger: Webhook node listening on /webhook/stripe-billing
2. Verify signature: Function node that verifies stripe-signature header against whsec_ secret
3. Extract data: Map Stripe event fields to PostHog properties:
   • event.type -> billing_event_type
   • event.data.object.customer -> use to look up PostHog distinct_id
   • event.data.object.plan.amount / 100 -> plan_amount_usd
   • event.data.object.plan.interval -> billing_interval
   • event.data.object.status -> subscription_status
4. Send to PostHog: HTTP Request node

Step 3: PostHog Capture

Send billing events to PostHog via the Capture API:

curl -X POST "https://us.i.posthog.com/capture/" \
  -H "Content-Type: application/json" \
  -d '{
    "api_key": "phc_xxx",
    "distinct_id": "user_xxx",
    "event": "billing_subscription_updated",
    "properties": {
      "plan_name": "pro",
      "plan_amount_usd": 49,
      "billing_interval": "month",
      "subscription_status": "active",
      "mrr_change": 49,
      "previous_plan": "free",
      "change_type": "upgrade"
    }
  }'

Key events to track:

| Stripe Event | PostHog Event | Key Properties | |-------------|---------------|----------------| | customer.subscription.created | billing_subscription_created | plan_name, plan_amount_usd, trial_end | | customer.subscription.updated | billing_subscription_updated | change_type (upgrade/downgrade), mrr_change | | customer.subscription.deleted | billing_subscription_canceled | cancel_reason, mrr_lost | | invoice.paid | billing_invoice_paid | amount_usd, period_start, period_end | | invoice.payment_failed | billing_payment_failed | failure_reason, attempt_count |

Step 4: Set Person Properties

In addition to events, update PostHog person properties so you can segment:

curl -X POST "https://us.i.posthog.com/capture/" \
  -H "Content-Type: application/json" \
  -d '{
    "api_key": "phc_xxx",
    "distinct_id": "user_xxx",
    "event": "$set",
    "properties": {
      "$set": {
        "current_plan": "pro",
        "mrr": 49,
        "billing_interval": "month",
        "subscription_status": "active",
        "plan_start_date": "2026-03-01"
      }
    }
  }'

Error Handling

• If PostHog capture fails, queue the event in n8n and retry (do not lose billing data)
• If Stripe webhook delivery fails 3 times, Stripe disables the endpoint — monitor via GET /v1/webhook_endpoints
• Validate distinct_id mapping: if a Stripe customer cannot be matched to a PostHog user, log it for manual resolution

Tool Options

| Source | Destination | Bridge | |--------|-------------|--------| | Stripe | PostHog | n8n webhook workflow | | Chargebee | PostHog | Chargebee webhooks + n8n | | Paddle | PostHog | Paddle Notifications + n8n | | Recurly | PostHog | Recurly webhooks + n8n | | Any | PostHog | Segment (if already using) |