PostHog Cost Tuning

Overview

Reduce PostHog event-based pricing costs by controlling event volume, optimizing autocapture settings, and leveraging the generous free tier. PostHog charges per event with a free tier of 1M events/month, then ~$0.00031 per event beyond that.

Prerequisites

• PostHog Cloud account with billing dashboard access

• Application instrumented with PostHog SDK

• Understanding of which events drive business value

Instructions

Step 1: Audit Event Volume by Type

set -euo pipefail

Check which events consume the most quota

curl "https://app.posthog.com/api/projects/PROJECT_ID/insights/trend/?events=[{\"id\":\"$pageview\"},{\"id\":\"$autocapture\"},{\"id\":\"$screen\"}]&date_from=-30d&interval=week"
-H "Authorization: Bearer $POSTHOG_PERSONAL_API_KEY" |
jq '.result[] | {event: .label, total_30d: (.data | add)}'

Step 2: Disable Unnecessary Autocapture

// posthog-init.ts - Configure autocapture to skip noisy elements posthog.init('phc_YOUR_KEY', { autocapture: { dom_event_allowlist: ['click', 'submit'], // Skip scroll, change, etc. element_allowlist: ['a', 'button', 'form', 'input[type=submit]'], css_selector_allowlist: ['.track-click'], // Only track explicitly marked elements url_ignorelist: ['/health', '/api/internal'], // Skip internal endpoints }, // Disable session recording for anonymous users to save on recording quota session_recording: { maskAllInputs: true, }, });

Step 3: Sample High-Volume Events

// Reduce non-critical event volume by sampling posthog.init('phc_YOUR_KEY', { // Only send 10% of pageview events (still statistically significant) before_send: (event) => { if (event.event === '$pageview') { return Math.random() < 0.1 ? event : null; // 90% reduction } // Always send business-critical events if (['purchase', 'signup', 'upgrade'].includes(event.event)) { return event; } // Sample other events at 50% return Math.random() < 0.5 ? event : null; }, });

Step 4: Filter Bot Traffic

// Bots generate significant event volume without business value posthog.init('phc_YOUR_KEY', { before_send: (event) => { const ua = navigator.userAgent.toLowerCase(); const isBot = /bot|crawler|spider|scrapy|headless|phantom/i.test(ua); return isBot ? null : event; }, });

Step 5: Monitor Monthly Costs

set -euo pipefail

Check current event usage vs billing tier

curl "https://app.posthog.com/api/organizations/ORG_ID/billing/"
-H "Authorization: Bearer $POSTHOG_PERSONAL_API_KEY" |
jq '{ events_used: .events_current_usage, events_limit: .events_plan_limit, usage_pct: (.events_current_usage / .events_plan_limit * 100), estimated_cost: (if .events_current_usage > 1000000 then ((.events_current_usage - 1000000) * 0.00031) else 0 end) # 1000000 = 1M limit }'

Error Handling

Issue Cause Solution

Event volume spike Autocapture on high-frequency element Add element to css_selector_denylist

Bill higher than expected Bot traffic generating events Add bot filtering in before_send

Missing critical events Sampling too aggressive Exclude business events from sampling

Free tier exceeded early New feature launched without volume estimate Forecast events before launch

Examples

Basic usage: Apply posthog cost tuning to a standard project setup with default configuration options.

Advanced scenario: Customize posthog cost tuning for production environments with multiple constraints and team-specific requirements.

Output

• Configuration files or code changes applied to the project

• Validation report confirming correct implementation

• Summary of changes made and their rationale

Resources

• Official monitoring documentation

• Community best practices and patterns

• Related skills in this plugin pack