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Flagsmith vs LangSmith

Flagsmith logo

Flagsmith

Software

Open-source feature flag and remote config platform

From
Free
Rated
-
Full reviewWebsite
L

LangSmith

Software

Know what your agents are really doing

From
On request
Rated
-
Full reviewWebsite

The short version

  • Only Flagsmith has a free tier, so it costs nothing to try first.
  • Each has a real cost: Flagsmith the Free plan supports only a single team member, limiting collaboration for small teams.; 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.

Where they differ

Only the attributes on which Flagsmith and LangSmith actually diverge.

Attributes where Flagsmith and LangSmith differ
AttributeFlagsmithLangSmith
Starting priceFreeOn request
Pricing modelfreemiumsubscription
Free tierYesNo
Platformsweb, apiWeb

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 Flagsmith

  • Feature flags
  • Segments
  • A/B testing
  • Scheduled flags
  • SDKs
  • SAML/SSO

Only in LangSmith

Nothing recorded that Flagsmith does not also cover.

What people use each for

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

Flagsmith

  • Gradual feature rollouts across environmentsnot LangSmith
  • Remote configuration without redeploying codenot LangSmith
  • Running A/B tests tied to feature flagsnot LangSmith
  • Self-hosting feature flags for data residency requirementsnot LangSmith

LangSmith

No use cases recorded yet. See the LangSmith review.

Where each one falls short

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

Flagsmith

  • The Free plan supports only a single team member, limiting collaboration for small teams.
  • Exceeding request limits triggers overage charges after a one-time 30-day grace period.
  • Enterprise-grade SSO and governance are locked behind the Scale-Up and Enterprise tiers.
  • Self-hosting requires operating and updating the platform yourself, unlike a fully managed SaaS competitor.

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.

Pricing, plan by plan

Flagsmith

Free
  • FreeFree
    • Up to 50,000 requests/month
    • 1 team member
    • Unlimited feature flags, environments, identities and segments
  • Start-Up$45/month
    • Up to 1,000,000 requests/month
    • 3 team members
    • Scheduled flags, 2FA, A/B testing, integrations, email support
  • Scale-Up$300/month
    • 5,000,000+ requests/month
    • 5-20 team members
    • SAML/SSO, governance features, priority support

LangSmith

On request

No published plan breakdown. See the LangSmith review.

Which should you pick?

Choose Flagsmith if

  • You need feature flags.
  • You want to start without paying.
  • You work on web, api.
  • You also want segments.
Flagsmith review

Choose LangSmith if

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

LangSmith review

Questions people ask

Is Flagsmith or LangSmith better?
Neither clearly leads. Flagsmith starts at Free and LangSmith at On request, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Flagsmith or LangSmith?
Flagsmith has a free tier; the other does not. Paid plans start at Free for Flagsmith and On request for LangSmith.
Does Flagsmith or LangSmith run on more platforms?
Flagsmith runs on web, api. LangSmith runs on Web.
Can I use Flagsmith for free?
Yes. Flagsmith has a free tier, so you can try it without paying. LangSmith starts at On request.
What is Flagsmith best used for?
Flagsmith is most often used for gradual feature rollouts across environments, remote configuration without redeploying code, running a/b tests tied to feature flags, self-hosting feature flags for data residency requirements. Of those, gradual feature rollouts across environments and remote configuration without redeploying code are not what LangSmith is typically brought in for.
What can Flagsmith do that LangSmith cannot?
Flagsmith covers Feature flags, Segments, A/B testing, Scheduled flags.

Answered from the vendors’ own pages

Flagsmith: What does Flagsmith cost?

Flagsmith has a Free plan, a Start-Up plan from $40-45/month, a Scale-Up plan from $250-300/month, and custom Enterprise pricing.

Source
Flagsmith: Is there a free plan, and what are its limits?

The Free plan supports up to 50,000 requests per month and 1 team member, with unlimited feature flags, environments, identities and segments.

Source
Flagsmith: How is usage metered?

Usage is metered by monthly API requests; exceeding a plan's limit triggers overage charges starting around $50 per million requests, with a 30-day grace period the first time a paid plan exceeds its limit.

Source
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