PostHog Review

Overview

PostHog is an open-source product analytics platform that combines event tracking, session replay, feature flags, A/B testing, and user surveys in a single tool. The generous free tier (1M events/month, 5K session replays) makes it accessible to startups and solo practitioners. For GTM Engineers who code, PostHog's developer-friendly approach and self-hosting option make it the analytics tool that fits their workflow best.

Unlike Segment (which routes data), PostHog analyzes it. You instrument PostHog's SDK, track events, and build funnels, retention charts, user paths, and dashboards directly in PostHog. Session replay lets you watch real user interactions. Feature flags let you roll out changes to segments of your user base. The all-in-one approach eliminates the need for separate tools for each capability.

PostHog launched as a Mixpanel/Amplitude alternative for developers. The product has matured significantly: SOC 2 compliance, EU data hosting, HIPAA-compliant options, and a growing set of enterprise features. The self-hosted version runs on your own infrastructure for full data control. The cloud version handles hosting for you with a usage-based pricing model.

GTM Engineer Use Cases

• Product-led growth analytics. Track trial-to-paid conversion funnels, feature adoption rates, and activation metrics. PostHog's funnel analysis shows where prospects drop off and which features correlate with conversion. GTM Engineers use this data to trigger outbound at drop-off points.
• Session replay for prospect research. Watch recordings of how prospects interact with your product during trials. See which features they explore, where they get confused, and what they try before churning. This informs personalized outbound messaging tied to observed behavior.
• Feature flag-driven A/B testing. Test different onboarding flows, pricing page layouts, and feature experiences with PostHog's built-in experimentation. GTM Engineers running product-led growth experiments can iterate without engineering bottlenecks.
• Event-triggered outbound workflows. PostHog's webhook destinations push events to n8n, Make, or custom endpoints. When a trial user hits a usage threshold, completes onboarding, or goes inactive for 3 days, trigger an automated outbound sequence.
• Custom dashboards for pipeline visibility. Build dashboards combining product usage data with pipeline metrics. Track which product actions correlate with closed deals. Share dashboards with sales teams to surface product-qualified leads.

Pricing Breakdown

Product	Free Tier	Paid (per unit)	Notes
Product Analytics	1M events/mo	$0.00031/event	Funnels, trends, paths, retention
Session Replay	5,000 recordings/mo	$0.005/recording	Full DOM capture, network tab
Feature Flags	1M requests/mo	$0.0001/request	Multivariate, percentage rollouts
Surveys	250 responses/mo	$0.20/response	Targeted in-app surveys

PostHog's free tier is the most generous in the analytics category. 1M events per month covers most early-stage SaaS products and internal tools. The usage-based pricing means you pay only for what you use, with no seat-based fees. A startup tracking 5M events per month pays roughly $120/month for analytics, which undercuts Mixpanel and Amplitude significantly.

Self-hosting is free with no event limits. You pay only for infrastructure. This is the option for companies that need data sovereignty, HIPAA compliance, or want to eliminate recurring analytics costs entirely. The tradeoff: you manage the deployment, scaling, and upgrades.

Honest Criticism

PostHog is product analytics, not marketing analytics. If you need multi-touch attribution, campaign performance tracking, or ad spend optimization, PostHog won't replace Google Analytics, HubSpot analytics, or a dedicated marketing analytics tool. The product tracks what users do inside your product. It doesn't track how they found you, which ads drove them, or which content influenced their purchase. GTM Engineers focused on top-of-funnel metrics need a separate tool.

Self-hosting requires infrastructure expertise. Running PostHog's ClickHouse-based analytics stack on your own servers demands familiarity with Kubernetes, database management, and monitoring. The minimum recommended spec (8 CPU, 32GB RAM for ClickHouse) means hosting costs $100-300/month for serious workloads. For most teams, cloud PostHog is simpler unless data sovereignty is a hard requirement.

Some enterprise features are still catching up to incumbents. PostHog has added group analytics, data warehouse queries, and SQL-based insights, but the depth of analysis in Mixpanel's advanced reports or Amplitude's behavioral cohorting is deeper in edge cases. For common analytics tasks (funnels, retention, user paths), PostHog matches competitors. For advanced statistical analysis on large datasets, the incumbents have a head start.

Verdict

PostHog is the best analytics tool for GTM Engineers who work on product-led growth. The combination of analytics, session replay, feature flags, and A/B testing in one platform with a generous free tier makes it the default choice for technical teams. The developer-friendly approach (API-first, open-source, self-hostable) matches how GTM Engineers prefer to work.

Use PostHog if you need product analytics (not marketing analytics), you want to avoid per-seat pricing, and you value the ability to self-host or access your data via API. Skip PostHog if you need marketing attribution, campaign analytics, or if your analytics needs are simple enough for Google Analytics. For GTM Engineers at companies already using Mixpanel or Amplitude, PostHog is worth evaluating for the cost savings and session replay features alone.

Frequently Asked Questions

Is PostHog free?

The cloud version includes 1M free events/month, 5K free session replays, and 1M free feature flag requests. Most early-stage products and internal tools stay within the free tier. The self-hosted version is free with no usage limits. You pay only for server hosting.

How does PostHog compare to Mixpanel?

PostHog offers analytics + session replay + feature flags + A/B testing in one tool. Mixpanel is pure analytics with deeper statistical features. PostHog's free tier (1M events) is more generous than Mixpanel's (20M events but limited features). PostHog is open-source and self-hostable. Mixpanel is cloud-only. For GTM Engineers who want one tool for analytics and experimentation, PostHog wins on breadth. For advanced behavioral analytics, Mixpanel has more depth.

Can I use PostHog for GTM workflows?

Yes, through event-triggered webhooks. When users hit specific events (trial signup, feature activation, usage threshold), PostHog can push those events to n8n, Make, or custom API endpoints. This enables product-qualified lead workflows where product behavior triggers outbound sales actions.

Is PostHog suitable for enterprise?

PostHog has SOC 2 Type II compliance, EU hosting, HIPAA options, SSO, and role-based access. Enterprise adoption is growing, with companies like Airbus and Phantom using PostHog. The main gap vs incumbents is in advanced governance features and dedicated support tiers, which PostHog is actively building.