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Technology · head to head

PostHog vs Thanos

PostHog logo

PostHog

Technology

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

From
Free
Rated
-
Full reviewWebsite
Thanos logo

Thanos

Cloud

Highly available Prometheus with long-term object storage

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; Thanos several components — sidecar, store, querier, compactor, ruler — each with its own configuration and failure modes
  • They diverge on capability: PostHog covers Product analytics, Thanos covers Global query.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which PostHog and Thanos actually diverge.

Attributes where PostHog and Thanos differ
AttributePostHogThanos
Pricing modelusage-basedOpen source, no licence fee
PlatformsWeb, Ios, Android, ApiKubernetes, Linux, Docker
CategoryTechnologyCloud
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 Thanos

  • Global query
  • Object storage retention
  • Deduplication
  • Downsampling

What people use each for

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

PostHog

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

Thanos

  • Querying metrics across many clusters or regions from one placenot PostHog
  • Retaining metrics for years without local disk growthnot PostHog
  • Removing the gap that appears when a single Prometheus instance restartsnot 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

Thanos

  • Several components — sidecar, store, querier, compactor, ruler — each with its own configuration and failure modes
  • The compactor is a common source of operational trouble and must not run twice against the same bucket
  • Query latency over object storage is meaningfully higher than local Prometheus
  • Object storage costs and API request charges become real at high volume

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

Thanos

Free
  • ThanosFree
    • Full functionality
    • No usage limits
    • 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 Thanos if

  • You need global query.
  • You want to start without paying.
  • You work on Kubernetes, Linux, Docker.
  • You also want object storage retention.
Thanos review

Questions people ask

Is PostHog or Thanos better?
Neither clearly leads. PostHog starts at Free and Thanos at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, PostHog or Thanos?
PostHog starts at Free and Thanos at Free.
Does PostHog or Thanos run on more platforms?
PostHog runs on Web, Ios, Android, Api. Thanos runs on Kubernetes, Linux, Docker.
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 Thanos is typically brought in for.
What can PostHog do that Thanos cannot?
PostHog covers Product analytics, Session recording, Feature flags, A/B testing. Thanos covers Global query, Object storage retention, Deduplication, Downsampling.

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
Thanos: Is Thanos free?

Yes, open source and CNCF-incubating. Costs are the object storage it uses.

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
Thanos: Does Thanos replace Prometheus?

No. It runs alongside existing Prometheus servers, adding global query, deduplication and long-term storage.

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
Thanos: Thanos or VictoriaMetrics?

Thanos layers onto Prometheus using object storage and is the more established multi-cluster answer. VictoriaMetrics is a separate store aiming at lower resource use and fewer moving parts.

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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