posthog-observability

name	posthog-observability
description	Monitor PostHog integration health: event ingestion rates, feature flag evaluation latency, billing volume tracking, and Prometheus/Grafana alerting. Trigger: "posthog monitoring", "posthog metrics", "posthog observability", "monitor posthog", "posthog alerts", "posthog dashboard".
allowed-tools	Read, Write, Edit
version	1.12.0
license	MIT
author	Jeremy Longshore <[e-mail]>
tags	["saas","posthog","monitoring","observability","dashboard"]
compatibility	Designed for Claude Code

PostHog Observability

Overview

Monitor PostHog integration health with four key signals: event ingestion rate (are events flowing?), feature flag evaluation latency (are flags fast enough for hot paths?), event volume by type (detect instrumentation regressions), and API rate limit consumption (are we approaching 429s?).

Prerequisites

• PostHog project with personal API key (phx_...)
• Application instrumented with PostHog SDK
• Prometheus/Grafana or equivalent monitoring stack (optional)

Instructions

Step 1: Event Ingestion Health Check

set -euo pipefail
# Check if events are flowing (last 24 hours)
curl "https://app.posthog.com/api/projects/$POSTHOG_PROJECT_ID/query/" \
  -H "Authorization: Bearer $POSTHOG_PERSONAL_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "query": {
      "kind": "HogQLQuery",
      "query": "SELECT toStartOfHour(timestamp) AS hour, count() AS events FROM events WHERE timestamp > now() - interval 24 hour GROUP BY hour ORDER BY hour"
    }
  }' | jq '.results | map({hour: .[0], events: .[1]}) | .[-3:]'

Step 2: Instrument Flag Evaluation Latency

// posthog-instrumented.ts
import { PostHog } from 'posthog-node';

const posthog = new PostHog(process.env.NEXT_PUBLIC_POSTHOG_KEY!, {
  host: 'https://us.i.posthog.com',
  personalApiKey: process.env.POSTHOG_PERSONAL_API_KEY,
});

// Wrap flag evaluation with timing
async function getFlag(flagKey: , : ): <> {
   start = performance.();
   value =  posthog.(flagKey, userId);
   durationMs = performance.() - start;

  
  (, durationMs, { : flagKey });
  (, , { : flagKey, : (value) });

  
   (durationMs > ) {
    .();
  }

   value;
}


 { , ,  }  ;

 flagDuration =  ({
  : ,
  : ,
  : [],
  : [, , , , , , , ],
});

 flagEvals =  ({
  : ,
  : ,
  : [, ],
});

 () {
  flagDuration.(labels, value);
}

 () {
  flagEvals.(labels, value);
}