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Software Development · head to head

Braintrust vs Flagsmith

Braintrust logo

Braintrust

Software Development

The active observability platform for agents

From
Free
Rated
-
Full reviewWebsite
Flagsmith logo

Flagsmith

Software Development

Open-source feature flag and remote config platform

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Braintrust enterprise plan pricing not published, requires custom quote; Flagsmith the Free plan supports only a single team member, limiting collaboration for small teams.
  • Prices and features above were last checked on 29 August 2026.

Where they differ

Only the attributes on which Braintrust and Flagsmith actually diverge.

Attributes where Braintrust and Flagsmith differ
AttributeBraintrustFlagsmith
PlatformsWebweb, api

Identical on both: starting price (Free), pricing model (freemium), free tier (Yes), user rating (Not yet rated), category (Software Development).

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 Braintrust

Nothing recorded that Flagsmith does not also cover.

Only in Flagsmith

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

What people use each for

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

Braintrust

  • Monitoring production AI agents for qualitynot Flagsmith
  • Detecting patterns in agent failuresnot Flagsmith
  • Defining quality expectations before shipping agentsnot Flagsmith
  • Tracking prompts and tool calls in productionnot Flagsmith

Flagsmith

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

Where each one falls short

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

Braintrust

  • Enterprise plan pricing not published, requires custom quote
  • Pro plan includes 6-12 months free discount for startups only

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.

Pricing, plan by plan

Braintrust

Free
  • StarterFree
    • $10 model credits monthly included
    • 1 GB processed data monthly
    • 10000 scores monthly
  • Pro$249/month
    • $249 model credits monthly included
    • 5 GB processed data monthly
    • 50000 scores monthly
  • Enterprise$null/month
    • Custom data retention and export capabilities
    • RBAC and premium support
    • On-premises or hosted solutions available

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

Which should you pick?

Choose Braintrust if

  • You want to start without paying.
Braintrust review

Choose Flagsmith if

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

Questions people ask

Is Braintrust or Flagsmith better?
Neither clearly leads. Braintrust starts at Free and Flagsmith at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Braintrust or Flagsmith?
Braintrust starts at Free and Flagsmith at Free.
Does Braintrust or Flagsmith run on more platforms?
Braintrust runs on Web. Flagsmith runs on web, api.
Can I use Braintrust for free?
Both have a free tier, so you can try either at no cost before committing.
What is Braintrust best used for?
Braintrust is most often used for monitoring production ai agents for quality, detecting patterns in agent failures, defining quality expectations before shipping agents, tracking prompts and tool calls in production. Of those, monitoring production ai agents for quality and detecting patterns in agent failures are not what Flagsmith is typically brought in for.
What can Braintrust do that Flagsmith cannot?
Flagsmith covers Feature flags, Segments, A/B testing, Scheduled flags.

Answered from the vendors’ own pages

Braintrust: Does Braintrust have a free plan?

Braintrust Starter plan is free and includes $10 model credits monthly, 1 GB processed data, 10000 scores monthly, and 14-day data retention with unlimited users and projects. No credit card required.

Source
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
Braintrust: How much does the Braintrust Pro plan cost?

Braintrust Pro plan costs $249 per month and includes $249 model credits, 5 GB processed data, 50000 scores monthly, and 30-day data retention. Qualifying startups receive 6-12 months free.

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
Braintrust: What are Braintrust's overage charges?

Braintrust charges overage rates after monthly allocations: model credits beyond monthly allotment are charged at token rates, data overage is $4 per GB on Starter or $3 per GB on Pro, scores overage is $2.50 per 1000 on Starter or $1.50 per 1000 on Pro. Extended data retention beyond the included period costs $0.50 per GB per month.

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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