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Software · head to head

LangSmith vs PostHog

L

LangSmith

Software

Know what your agents are really doing

From
On request
Rated
-
Full reviewWebsite
PostHog logo

PostHog

Software

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

From
Free
Rated
-
Full reviewWebsite

The short version

  • Only PostHog has a free tier, so it costs nothing to try first.
  • Each has a real cost: LangSmith usage beyond the included trace allotment is billed in LangChain Compute Units at $1.50 per LCU and Storage Units at $1.00 per LSU, an unfamiliar metering unit compared to flat per-seat pricing, as of August 2026.; PostHog the free tier covers 1M events, 5K web session recordings and 2.5K mobile recordings per month before usage-based billing starts

Where they differ

Only the attributes on which LangSmith and PostHog actually diverge.

Attributes where LangSmith and PostHog differ
AttributeLangSmithPostHog
Starting priceOn requestFree
Pricing modelsubscriptionusage-based
Free tierNoYes
PlatformsWebWeb, Ios, Android, Api
FoundedUnknown2020

Identical on both: user rating (Not yet rated), category (Unknown).

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 LangSmith

Nothing recorded that PostHog does not also cover.

Only in PostHog

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

What people use each for

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

LangSmith

No use cases recorded yet. See the LangSmith review.

PostHog

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

Where each one falls short

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

LangSmith

  • Usage beyond the included trace allotment is billed in LangChain Compute Units at $1.50 per LCU and Storage Units at $1.00 per LSU, an unfamiliar metering unit compared to flat per-seat pricing, as of August 2026.

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

Pricing, plan by plan

LangSmith

On request

No published plan breakdown. See the LangSmith review.

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

Which should you pick?

Choose LangSmith if

Nothing in the data separates LangSmith from PostHog on the points above - pick on price and on how each one feels to use.

LangSmith review

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

Questions people ask

Is LangSmith or PostHog better?
Neither clearly leads. LangSmith starts at On request and PostHog at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, LangSmith or PostHog?
PostHog has a free tier; the other does not. Paid plans start at On request for LangSmith and Free for PostHog.
Does LangSmith or PostHog run on more platforms?
LangSmith runs on Web. PostHog runs on Web, Ios, Android, Api.
Can I use PostHog for free?
Yes. PostHog has a free tier, so you can try it without paying. LangSmith starts at On request.
What can LangSmith do that PostHog cannot?
PostHog covers Product analytics, Session recording, Feature flags, A/B testing.
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