13 — Observability and Growth
Tiered PostHog+Sentry+GA4 stacks wired from day one; feature flags, PLG patterns, incident auto-remediation.
Instrumentation tiers
Per _kernel/standards.md#integrations:
- Tier 1 (solo) — PostHog + Workers Tracing OTLP (2 vendors max, cookie-free, free tier covers <10k MAU)
- Tier 2 (enterprise) — + Sentry @sentry/cloudflare v9 + GA4/GTM + Axiom
- Tier 3 (LLM-heavy >10k calls/mo) — + AI Gateway
PostHog (Tier 1 cornerstone)
- Snippet on every HTML page w/
persistence:'memory' (cookie-free); capture_pageview + capture_pageleave + autocapture:true
- Unified platform: product analytics + feature flags + session replay + error tracking
- CSP:
script-src + connect-src for posthog domain
- Per-feature event naming:
<feature>:<action> (signup:complete, editor:save, share:copy)
Sentry (Tier 2)
@sentry/cloudflare v9 + withSentry wrapper; project via mcp__sentry__create_project (org:megabyte-labs)SENTRY_DSN via wrangler secret put- Pattern:
withSentry(env => ({ dsn, tracesSampleRate: 1.0, sendDefaultPii: false }), worker)
- Breadcrumbs before risky ops; capture exception w/ context tags (
worker | route | userId)
- Release tracking via
SENTRY_RELEASE env; Workers Tracing handles I/O spans
Workers Tracing (Tier 1 + 2) / GA4 + GTM (Tier 2) / AI Gateway (Tier 3)
- Workers Tracing:
[observability] enabled = true in wrangler.jsonc — zero-config OTel I/O tracing; export to Axiom, Honeycomb, Grafana, Datadog via @opentelemetry/exporter-trace-otlp-http
- GA4 + GTM: container snippet (head script + noscript iframe); CSP:
googletagmanager.com + google-analytics.com + analytics.google.com + region1.google-analytics.com; server-side tagging for EU; custom dimensions over custom events
- AI Gateway:
env.AI.run() auto-routes; direct Anthropic: https://gateway.ai.cloudflare.com/v1/{account}/{gateway}/anthropic/v1/messages; caching + rate-limit + fallback + per-call logging
Stripe (SaaS billing only — per rules/payments-routing.md)
- Webhook-first w/ idempotent processing (D1 dedupe table
payment_events(event_id, source, processed_at) UNIQUE)
Stripe-Signature HMAC + 5-min replay window- Mint products + prices via MCP (idempotent via
lookup_key); subscription state machine in D1
STRIPE_WEBHOOK_SECRET via POST /v1/webhook_endpoints
Square (accept-money default — per rules/payments-routing.md)
- Square Web Payments SDK card form + Apple Pay + Google Pay + Cash App Pay
Square-Signature HMAC-SHA256 w/ 6-hr replay window; idempotency_key UUID per request (24-hr dedupe)- Nonprofit verified-501c3 discount (2.6%+10¢ vs 3.5%+15¢)
Listmonk (newsletter — self-hosted on Coolify)
- Amazon SES SMTP relay (
LISTMONK_FROM_EMAIL); listmonkSendTx(env, { templateAlias, ... }) via KV-cached alias→id map
- Templates in
emails/*.html synced via scripts/listmonk-sync.mjs
- Auth:
Authorization: token <user>:<key> (Listmonk 3.x API-user pattern)
PLG 7-Layer Framework
- Discovery — SEO + AI search + word-of-mouth + paid
- Sign-up — passwordless preferred (Clerk M2M JWT)
- Activation — first-value-in-X-min metric (aha moment per
rules/feature-flags.md instrumentation)
- Engagement — DAU/MAU ratio, session depth
- Retention — D1/D7/D30 cohort
- Revenue — upgrade trigger, expansion
- Referral — viral coefficient, two-sided rewards
Programmatic SEO (5 page types)
/integrations/{tool} · /compare/{a}-vs-{b} · /for/{audience} · /templates/{type} · /{city}-{service}- Each: unique H1 + meta desc + 800+ unique words + 1 unique image + 3+ internal links + 1+ outbound citation. Cap 200 pages per axis.
- Per
rules/copy-writing.md § pSEO + rules/thin-source-amplification.md.
GEO / AI search
- Quotable answer blocks 40-60 words (LLM citation magnet); FAQPage schema highest AI-citation rate (ChatGPT / Perplexity / Google AI Overviews)
- JSON-LD facts MUST also appear as visible HTML body text; lead paragraphs answer query in <40 words
- EEAT: author bio +
Person schema + sameAs + dated revision + ownership statement
llms.txt at site root (DX-only, <0.3% adoption — not build gate)
Local-business conversions + CRO
Track per local-conversions.md: phone_click (tel:) · direction_click (Google Maps) · form_submit · booking_click (Calendly/Cal.com) · chat_click · review_click (Google Business/Yelp). Each fires PostHog + Sentry breadcrumb + (Tier 2) GA4 conversion event.
CRO: sticky CTA bar on mobile · scroll-progress bar (subtle) · exit-intent modal (cart/pricing only, not blogs) · social proof near every CTA · urgency without dark patterns ("3 spots left this week" if true) · trust strip above fold · single primary CTA per surface.
Incident auto-remediation
Sentry → Inngest pipeline: (1) Sentry webhook on event.alert.triggered → (2) Inngest dispatches incident-responder agent → (3) agent reads event, traces to source file, proposes fix, opens PR via gh MCP → (4) PR auto-merges if all CI gates pass per rules/ai-seniority.md.
See submodules: posthog, ga4-gtm, sentry, stripe-billing, square-payments, listmonk, plg-framework, programmatic-seo, incident-remediation, geo-ai-search, local-conversions.
1---2name: observability-and-growth3description: Full instrumentation from day one. PostHog consolidates product analytics + feature flags + error tracking (one platform, one bill). GA4 via GTM (14-step automation, custom dimensions over events, server-side tagging). Sentry (deep error tracking + performance). Stripe (webhook-first with idempotent processing). Listmonk on Coolify (newsletters via Amazon SES SMTP relay). PLG 7-layer framework. Programmatic SEO (5 page types). Incident auto-remediation via Sentry→Inngest pipeline. AI search (GEO) awareness. Local business conversions (phone_click, direction_click, form_submit, booking_click) with CRO patterns for both SaaS and local.4license: Rutgers5---67# 13 — Observability and Growth89Tiered PostHog+Sentry+GA4 stacks wired from day one; feature flags, PLG patterns, incident auto-remediation.1011## Instrumentation tiers1213Per `_kernel/standards.md#integrations`:1415- **Tier 1 (solo)** — PostHog + Workers Tracing OTLP (2 vendors max, cookie-free, free tier covers <10k MAU)16- **Tier 2 (enterprise)** — + Sentry @sentry/cloudflare v9 + GA4/GTM + Axiom17- **Tier 3 (LLM-heavy >10k calls/mo)** — + AI Gateway1819## PostHog (Tier 1 cornerstone)2021- Snippet on every HTML page w/ `persistence:'memory'` (cookie-free); `capture_pageview` + `capture_pageleave` + `autocapture:true`22- Unified platform: product analytics + feature flags + session replay + error tracking23- CSP: `script-src` + `connect-src` for posthog domain24- Per-feature event naming: `<feature>:<action>` (`signup:complete`, `editor:save`, `share:copy`)2526## Sentry (Tier 2)2728- `@sentry/cloudflare` v9 + `withSentry` wrapper; project via `mcp__sentry__create_project` (org:`megabyte-labs`)29- `SENTRY_DSN` via `wrangler secret put`30- Pattern: `withSentry(env => ({ dsn, tracesSampleRate: 1.0, sendDefaultPii: false }), worker)`31- Breadcrumbs before risky ops; capture exception w/ context tags (`worker` | `route` | `userId`)32- Release tracking via `SENTRY_RELEASE` env; Workers Tracing handles I/O spans3334## Workers Tracing (Tier 1 + 2) / GA4 + GTM (Tier 2) / AI Gateway (Tier 3)3536- Workers Tracing: `[observability] enabled = true` in `wrangler.jsonc` — zero-config OTel I/O tracing; export to Axiom, Honeycomb, Grafana, Datadog via `@opentelemetry/exporter-trace-otlp-http`37- GA4 + GTM: container snippet (head script + noscript iframe); CSP: `googletagmanager.com` + `google-analytics.com` + `analytics.google.com` + `region1.google-analytics.com`; server-side tagging for EU; custom dimensions over custom events38- AI Gateway: `env.AI.run()` auto-routes; direct Anthropic: `https://gateway.ai.cloudflare.com/v1/{account}/{gateway}/anthropic/v1/messages`; caching + rate-limit + fallback + per-call logging3940## Stripe (SaaS billing only — per `rules/payments-routing.md`)4142- Webhook-first w/ idempotent processing (D1 dedupe table `payment_events(event_id, source, processed_at)` UNIQUE)43- `Stripe-Signature` HMAC + 5-min replay window44- Mint products + prices via MCP (idempotent via `lookup_key`); subscription state machine in D145- `STRIPE_WEBHOOK_SECRET` via `POST /v1/webhook_endpoints`4647## Square (accept-money default — per `rules/payments-routing.md`)4849- Square Web Payments SDK card form + Apple Pay + Google Pay + Cash App Pay50- `Square-Signature` HMAC-SHA256 w/ 6-hr replay window; `idempotency_key` UUID per request (24-hr dedupe)51- Nonprofit verified-501c3 discount (2.6%+10¢ vs 3.5%+15¢)5253## Listmonk (newsletter — self-hosted on Coolify)5455- Amazon SES SMTP relay (`LISTMONK_FROM_EMAIL`); `listmonkSendTx(env, { templateAlias, ... })` via KV-cached alias→id map56- Templates in `emails/*.html` synced via `scripts/listmonk-sync.mjs`57- Auth: `Authorization: token <user>:<key>` (Listmonk 3.x API-user pattern)5859## PLG 7-Layer Framework60611. **Discovery** — SEO + AI search + word-of-mouth + paid622. **Sign-up** — passwordless preferred (Clerk M2M JWT)633. **Activation** — first-value-in-X-min metric (aha moment per `rules/feature-flags.md` instrumentation)644. **Engagement** — DAU/MAU ratio, session depth655. **Retention** — D1/D7/D30 cohort666. **Revenue** — upgrade trigger, expansion677. **Referral** — viral coefficient, two-sided rewards6869## Programmatic SEO (5 page types)7071- `/integrations/{tool}` · `/compare/{a}-vs-{b}` · `/for/{audience}` · `/templates/{type}` · `/{city}-{service}`72- Each: unique H1 + meta desc + 800+ unique words + 1 unique image + 3+ internal links + 1+ outbound citation. Cap 200 pages per axis.73- Per `rules/copy-writing.md` § pSEO + `rules/thin-source-amplification.md`.7475## GEO / AI search7677- Quotable answer blocks 40-60 words (LLM citation magnet); FAQPage schema highest AI-citation rate (ChatGPT / Perplexity / Google AI Overviews)78- JSON-LD facts MUST also appear as visible HTML body text; lead paragraphs answer query in <40 words79- EEAT: author bio + `Person` schema + `sameAs` + dated revision + ownership statement80- `llms.txt` at site root (DX-only, <0.3% adoption — not build gate)8182## Local-business conversions + CRO8384Track per `local-conversions.md`: `phone_click` (`tel:`) · `direction_click` (Google Maps) · `form_submit` · `booking_click` (Calendly/Cal.com) · `chat_click` · `review_click` (Google Business/Yelp). Each fires PostHog + Sentry breadcrumb + (Tier 2) GA4 conversion event.8586CRO: sticky CTA bar on mobile · scroll-progress bar (subtle) · exit-intent modal (cart/pricing only, not blogs) · social proof near every CTA · urgency without dark patterns ("3 spots left this week" if true) · trust strip above fold · single primary CTA per surface.8788## Incident auto-remediation8990Sentry → Inngest pipeline: (1) Sentry webhook on `event.alert.triggered` → (2) Inngest dispatches `incident-responder` agent → (3) agent reads event, traces to source file, proposes fix, opens PR via gh MCP → (4) PR auto-merges if all CI gates pass per `rules/ai-seniority.md`.9192## See submodules: posthog, ga4-gtm, sentry, stripe-billing, square-payments, listmonk, plg-framework, programmatic-seo, incident-remediation, geo-ai-search, local-conversions.
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