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Monitoring Stack for SaaS: Sentry, PostHog, and Plausible
The triad we install on nearly all our projects: error tracking, product analytics, and privacy-first traffic analytics.
Three kinds of data you should track
| Type | Why | Tools |
|---|---|---|
| Errors & Performance | Know about breakage before users complain | Sentry, Highlight |
| Product Analytics | Which features are used, conversion funnels | PostHog, Mixpanel, Amplitude |
| Traffic Analytics | Site traffic & SEO performance | Plausible, Fathom, GA4 |
1. Sentry — error tracking
Set up in Astro / Next.js / Node:
npx @sentry/wizard@latest -i nextjsThe wizard handles config + DSN env. Then:
- Sample rate — don’t run 100% in prod to conserve quota. Start at 10%, raise as needed.
- Filter noise — exclude bot errors and browser-extension errors.
- Source maps — auto-upload from your build CI so stack traces are readable.
- Release tag — tag each deploy with the commit SHA to track regressions.
Alerts: hook to WhatsApp via webhook → the team is notified in minutes.
2. PostHog — product analytics
Self-hosted is free; cloud Free tier covers 1M events/month. Why over Mixpanel:
- Session replay — see real (anonymized) users interacting.
- Feature flags — A/B testing without an external tool.
- Funnels — track signup → activation → paid conversion.
Minimum setup:
posthog.init('phc_xxx', { api_host: 'https://app.posthog.com' });
// Track an event
posthog.capture('signup_completed', {
plan: 'pro',
source: 'landing_page',
});Only track meaningful events: signup, activation milestones, paid conversion, churn signals.
3. Plausible — traffic analytics
GA4 keeps getting more complex (event-based, sprawling UI, privacy issues). Plausible:
- Privacy-friendly — no cookies, GDPR-compliant by default.
- One-page UI — every metric in a single dashboard.
- Lightweight — script < 1 KB.
- Self-host for free or cloud at $9/month.
Setup in <head>:
<script defer
data-domain="lancartech.co.id"
src="https://plausible.io/js/script.js"></script>Track: pageviews, unique visitors, top pages, sources, devices, location. For Indonesian SEO, Plausible is enough.
Our standard stack
For SaaS clients:
- Sentry (errors + perf, ~$26/month for small teams)
- PostHog cloud free tier (until user growth, then upgrade)
- Plausible self-hosted (free on the in-house server, or $9/month cloud)
- Optional: Healthchecks.io for cron monitoring
Total: < $50/month for full observability.
Often missed
- Real User Monitoring (RUM) — Sentry supports it; enable for real-user Core Web Vitals.
- Custom dashboard — a single Notion/Slack daily digest pulling from all tools.
- Alert hierarchy — critical (page down) to WhatsApp, warning (high error rate) to Slack.
