LangSmith vs Braintrust 2026: Platform Depth vs Transparent Unit Pricing
Quick verdict: LangSmith is our overall pick for langsmith vs braintrust.
- Best overall: LangSmith (4.4/5)
- Best free: Braintrust
- Best for teams: LangSmith
- Pricing last checked: 2026-10-03
LangSmith ($39/seat, then $1.00/LSU) covers the whole agent platform; Braintrust ($0 to 10K scores, then $249/mo) prices exactly what a scored output costs and publishes every rate.
| Tool | Rating | Pricing | Best for |
|---|---|---|---|
| LangSmith Best overall Best for teams | 4.4/5 | Free $39/seat/mo (Plus) | LangSmith is the observability and evaluation platform from the LangChain team: $0/seat wi… |
| Braintrust Best free | 4.2/5 | Free $249/mo (Pro) | Braintrust is the observability and eval platform with the most explicit score pricing in … |
Bottom line: Braintrust wins on predictability of the evaluation bill - you can forecast it from published per-1K score rates before signing anything. LangSmith wins on everything that is not the evaluation bill: framework integration breadth, deployment, and the autonomous debugging engine. If your workload is scoring-heavy and cost-sensitive, Braintrust is easier to model; if your agents need deployment and diagnostics, LangSmith absorbs work Braintrust leaves you. See also Langfuse for the gentler price curve.
Pricing and details
LangSmith · 4.4/5
Free plan available · $39/seat/mo (Plus)
Trace volume is metered in LangChain Standard Units (LSU) at $1.00/LSU on top of the seat fee; base traces carry 14-day retention, extended traces 180 days, and retention auto-upgrades can raise your bill
No annual pricing published on the LangSmith pricing page
LangSmith is the observability and evaluation platform from the LangChain team: $0/seat with 5K base traces a month, Plus at $39/seat with 10K, then pay-as-you-go at $1.00 per LangChain Standard Unit.
Score breakdown
Pros
- Widest platform in the cluster - tracing, monitoring, evaluation, prompt hub, deployment, sandboxes and an autonomous debugging engine under one login
- The only vendor that publishes its metering unit (LSU at $1.00) and per-resource rates, so a bill can be estimated before you commit
- 14-day base and 180-day extended retention are documented explicitly, including which actions upgrade a trace and which do not
- Native integrations for the major agent frameworks plus OpenTelemetry SDKs for Python, TypeScript, Go and Java
Cons
- Retention auto-upgrades are the bill trap: online evaluators and automation rules push matching traces to the pricier extended tier unless you opt out per evaluator
- Extended retention for SaaS tops out at 180 days as of 2026-09-14, so long-horizon analysis has to go to Enterprise customization
- Plus is $39/seat with unlimited seats, which punishes a wide read-only audience paying for observability they do not act on
Pricing verified 2026-10-03
Braintrust · 4.2/5
Free plan available · $249/mo (Pro)
Scored outputs are the billing unit (LLM-as-a-judge, autoevals, custom scorers) alongside processed data and model credits; retention beyond 30 days is billed at $0.50/GB/mo up to 180 days on Pro
No published annual rate; Pro offers 6-12 months free for qualifying startups
Braintrust is the observability and eval platform with the most explicit score pricing in the cluster: Starter is $0 with 10K scores a month, Pro jumps to $249/mo with 50K scores plus cheaper per-1K rates.
Score breakdown
Pros
- The most explicit pricing in the cluster: scores are named as the billing unit with rates ($2.50/1K on Starter, $1.50/1K on Pro), processed data and model credits are listed line by line
- Starter is genuinely free with unlimited users, projects, datasets, playgrounds and experiments - no card required
- Retention is priced rather than hidden: 14 days included on Starter, 30 on Pro, then $0.50/GB/mo up to 180 days
- 6-12 months free for qualifying startups, and an open research program with published foundations
Cons
- The Starter-to-Pro step is $0 to $249/mo, so a team that crosses 10K scored outputs a month faces a large step rather than a gradual bill
- Custom charts, environments, priority support and RBAC are Pro-only, so the free tier is genuinely basic
- No S3 data export or custom retention policies until Enterprise
Pricing verified 2026-10-03
Frequently asked questions
Which is better overall, LangSmith or Braintrust?
LangSmith is our overall pick (4.4/5 vs 4.2/5). LangSmith ($39/seat, then $1.00/LSU) covers the whole agent platform; Braintrust ($0 to 10K scores, then $249/mo) prices exactly what a scored output costs and publishes every rate.
Do LangSmith and Braintrust offer free plans?
LangSmith and Braintrust have a free tier. LangSmith paid plans start at $39/seat/mo (Plus); Braintrust paid plans start at $249/mo (Pro).
What does LangSmith cost?
$39/seat/mo (Plus) — Trace volume is metered in LangChain Standard Units (LSU) at $1.00/LSU on top of the seat fee; base traces carry 14-day retention, extended traces 180 days, and retention auto-upgrades can raise your bill. Prices were last verified on 2026-10-03.