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Technology · head to head

PostHog vs Valkey

PostHog logo

PostHog

Technology

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

From
Free
Rated
-
Full reviewWebsite
Valkey logo

Valkey

Databases

Open-source in-memory data store forked from Redis

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; Valkey younger project, so its track record is short even though the codebase is not
  • They diverge on capability: PostHog covers Product analytics, Valkey covers Redis-compatible.

Where they differ

Only the attributes on which PostHog and Valkey actually diverge.

Attributes where PostHog and Valkey differ
AttributePostHogValkey
Pricing modelusage-basedOpen source, no licence fee; managed cloud billed separately
PlatformsWeb, Ios, Android, ApiLinux, macOS, Docker, Self-hosted
CategoryTechnologyDatabases
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 Valkey

  • Redis-compatible
  • BSD licensed
  • Rich data structures
  • Replication and persistence

What people use each for

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

PostHog

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

Valkey

  • Continuing on a permissively licensed in-memory store after the Redis licence changenot PostHog
  • Caching and session storage where a foundation-governed project is a procurement requirementnot PostHog
  • Migrating from Redis without rewriting application codenot 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

Valkey

  • Younger project, so its track record is short even though the codebase is not
  • Divergence from Redis grows over time, so compatibility is strongest near the fork point and weakens as both evolve
  • Ecosystem tooling and documentation still frequently assume Redis, leaving translation work

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

Valkey

Free
  • ValkeyFree
    • Full functionality
    • Self-hosted
    • No usage limits

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 Valkey if

  • You need redis-compatible.
  • You want to start without paying.
  • You work on Linux, macOS, Docker, Self-hosted.
  • You also want bsd licensed.
Valkey review

Questions people ask

Is PostHog or Valkey better?
Neither clearly leads. PostHog starts at Free and Valkey at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, PostHog or Valkey?
PostHog starts at Free and Valkey at Free.
Does PostHog or Valkey run on more platforms?
PostHog runs on Web, Ios, Android, Api. Valkey runs on Linux, macOS, Docker, Self-hosted.
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 Valkey is typically brought in for.
What can PostHog do that Valkey cannot?
PostHog covers Product analytics, Session recording, Feature flags, A/B testing. Valkey covers Redis-compatible, BSD licensed, Rich data structures, Replication and persistence.

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
Valkey: Is Valkey free?

Yes, BSD-licensed open source under the Linux Foundation.

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
Valkey: Why does Valkey exist?

Redis changed its licence away from BSD in 2024. Valkey is the community fork continuing under permissive terms, backed by AWS, Google Cloud and Oracle among others.

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
Valkey: Can I switch from Redis to Valkey?

At the fork point it is drop-in compatible with existing clients and data. The further both projects move from that point, the more you should verify the specific features you use.

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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