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Technology · head to head

PostHog vs Radix UI

PostHog logo

PostHog

Technology

The single platform to analyze, test, observe, and deploy new features

From
Free
Rated
-
Full reviewWebsite
Radix UI logo

Radix UI

Web Development

Unstyled, accessible React component primitives

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: PostHog the free tier covers 1M events, 5K web session recordings and 2.5K mobile recordings per month before usage-based billing starts; Radix UI you write all the styling, so time to a finished interface is much longer than with a styled library
  • They diverge on capability: PostHog covers Product analytics, Radix UI covers Unstyled primitives.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which PostHog and Radix UI actually diverge.

Attributes where PostHog and Radix UI differ
AttributePostHogRadix UI
Pricing modelusage-basedOpen source, no licence fee
PlatformsWeb, Ios, Android, ApiWeb
CategoryTechnologyWeb Development
Founded2020Unknown

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in PostHog

  • Product analytics
  • Session recording
  • Feature flags
  • A/B testing
  • Heatmaps
  • SQL access
  • Data warehouse
  • Apps platform

Only in Radix UI

  • Unstyled primitives
  • Accessibility built in
  • Composable API
  • Controlled or uncontrolled

What people use each for

The jobs each tool is most often brought in to do.

PostHog

  • Product analyticsnot Radix UI
  • Feature experimentationnot Radix UI
  • User behavior trackingnot Radix UI
  • A/B testingnot Radix UI
  • Debug production issuesnot Radix UI

Radix UI

  • Design systems that need correct accessibility without inherited visual opinionsnot PostHog
  • Replacing hand-built dropdowns and dialogs that have accessibility bugsnot PostHog
  • Teams with a designer whose output should not be constrained by a library’s themenot PostHog

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

PostHog

  • The free tier covers 1M events, 5K web session recordings and 2.5K mobile recordings per month before usage-based billing starts
  • Accounts without a card on file are limited to 1 project; adding one raises it to 6
  • Data retention is 1 year until a card is added, which extends it to 7 years
  • Support is community-only until the account is on a paid plan
  • Error tracking is capped at 100K exceptions and surveys at 1500 responses per month on the free tier

Radix UI

  • You write all the styling, so time to a finished interface is much longer than with a styled library
  • Composable part-based APIs are more verbose than a single component with props
  • Covers primitives rather than complex widgets, so data grids and date pickers come from elsewhere

Pricing, plan by plan

PostHog

Free
  • FreeFree
    • 1M events/month
    • 5K sessions/month
    • Unlimited users
  • Paid$undefined/month
    • $0.00031/event
    • $0.005/session
    • Advanced permissions
  • Enterprise$undefined/month
    • SAML SSO
    • Advanced security
    • Dedicated support

Radix UI

Free
  • Radix UIFree
    • Full functionality
    • Commercial use permitted
    • Community support

Which should you pick?

Choose PostHog if

  • You need product analytics.
  • You want to start without paying.
  • You work on Web, Ios, Android, Api.
  • You also want session recording.
PostHog review

Choose Radix UI if

  • You need unstyled primitives.
  • You want to start without paying.
  • You also want accessibility built in.
Radix UI review

Questions people ask

Is PostHog or Radix UI better?
Neither clearly leads. PostHog starts at Free and Radix UI at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, PostHog or Radix UI?
PostHog starts at Free and Radix UI at Free.
Does PostHog or Radix UI run on more platforms?
PostHog runs on Web, Ios, Android, Api. Radix UI runs on Web.
Can I use PostHog for free?
Both have a free tier, so you can try either at no cost before committing.
What is PostHog best used for?
PostHog is most often used for product analytics, feature experimentation, user behavior tracking, a/b testing. Of those, product analytics and feature experimentation are not what Radix UI is typically brought in for.
What can PostHog do that Radix UI cannot?
PostHog covers Product analytics, Session recording, Feature flags, A/B testing. Radix UI covers Unstyled primitives, Accessibility built in, Composable API, Controlled or uncontrolled.

Answered from the vendors’ own pages

PostHog: What does PostHog's free tier include per month?

PostHog free tier includes: 1M analytics events, 5K session replays, 1M feature flag requests, 100K error tracking exceptions, 1,500 survey responses, 1M data warehouse rows, 10K data pipeline events, 100K AI observability events, 500 PostHog AI credits, 10K workflow messages, and 10GB log ingestion. Source: https://posthog.com/pricing

Source
Radix UI: Is Radix UI free?

Yes, open source under the MIT licence.

PostHog: How much data retention does PostHog provide on paid plans?

PostHog free tier provides 1-year data retention. Pay-as-you-go plans offer 7-year data retention across all projects, enabling longer historical analysis. Source: https://posthog.com/pricing

Source
Radix UI: Why use unstyled components?

Because accessibility is the hard part and visual design is the part teams want to own. Radix gives the first and stays out of the second.

PostHog: What percentage of PostHog users stay on the free tier?

PostHog states that 97% of companies use PostHog for free, indicating extensive free tier adoption. However, specific per-unit pricing rates for overages on paid plans are not published. Source: https://posthog.com/pricing

Source
Radix UI: What is the relationship with shadcn/ui?

shadcn/ui is built on Radix primitives, adding Tailwind styling and copy-paste distribution on top.

PostHog: When does PostHog provide priority support on paid plans?

PostHog provides email or Slack support for accounts exceeding $2,000/month on pay-as-you-go plans. Specific response times and support SLAs are not detailed on their pricing page. Source: https://posthog.com/pricing

Source
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