What each one actually is
Amplitude is a dedicated product-analytics platform built around deep behavioral cohorting, retention analysis, and its own experimentation and CDP add-ons layered on top. PostHog is an all-in-one product engineering platform: product analytics, feature flags, session replay, surveys, and a data warehouse connection, released open-source with a self-hosted option alongside its cloud product.
Dimension by dimension
| Dimension | Amplitude | PostHog |
|---|---|---|
| Core focus | Dedicated, deep behavioral product analytics | All-in-one: analytics, flags, replay, surveys together |
| Deployment | Hosted SaaS only | Cloud or self-hosted (open-source core) |
| Pricing model | Usage/event-volume based, tiered plans | Usage-based per product, generous free tier |
| Feature flags | Separate add-on / experimentation product | Built into the core platform |
| Session replay | Not a native product | Built in natively |
| Ecosystem maturity | Long-established, deep enterprise cohort tooling | Newer, faster iteration, open-source community |
Packaging and feature scope shift on both sides over time - verify current specifics against each vendor before a purchasing decision.
The deciding questions
- Do you want one platform or a best-of-breed stack? If flags, replay, and analytics under one roof reduces total tooling, PostHog's argument is straightforward. If you already run separate best-of-breed tools well, consolidation may not be the win it looks like on paper.
- Does your team lean on deep Amplitude-specific cohort workflows? That is real switching cost to weigh, not just a line-item price comparison.
- Is self-hosting a real requirement or a nice-to-have? If data residency or infrastructure control matters, that alone can decide it - Amplitude does not offer a self-hosted path.
Full disclosure of perspective: we run a dedicated Amplitude practice alongside this PostHog practice - we work both sides of this decision, which is exactly why neither answer here is reflexive.