LangSmith vs Helicone 2026: Full Trace Trees Against a One-Line Proxy Log
Quick verdict: LangSmith is our overall pick for langsmith vs helicone.
Helicone installs in one line and prices per request ($79/mo Pro); LangSmith gives full agent trace trees, evaluation and deployment at $39/seat plus usage.
| 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… |
| Helicone Best free | 3.8/5 | Free $79/mo (Pro) | Helicone is the request-level observability and gateway layer priced per request: Hobby fr… |
Bottom line: Helicone if you want visibility into requests, caching and routing and nothing deeper - it is a proxy layer, and it is honest about that. LangSmith if you need to know what your agent did and why, with trace trees, evaluation and a debugging engine. They are not really substitutes: Helicone sits at the HTTP layer, LangSmith at the application layer. Note also that Helicone has joined Mintlify. See Langfuse for a middle option with real tracing.
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
Helicone · 3.8/5
Free plan available · $79/mo (Pro)
Requests are the billing unit and usage-based pricing applies on top of every paid tier; storage beyond 1 GB is usage-billed, and Helicone announced it has joined Mintlify
No published annual rate; published discounts are 50% off year one for startups under 2 years old and under $5M raised, org-size-based non-profit discounts, a $100 first-year credit for open-source companies and free plans for students
Helicone is the request-level observability and gateway layer priced per request: Hobby free with 10,000 requests a month, Pro at $79/mo, Team at $799/mo, and usage-based pricing on top.
Score breakdown
Pros
- The easiest adoption story in the cluster - a one-line integration, the clearest interface of the five, and no framework lock-in since it sits at the request layer
- Straightforward request-based pricing with a published calculator: 10K free requests, then usage-based billing on every paid tier
- Caching, rate limits, automatic fallbacks and a gateway ship in the same product, so observability and routing are one purchase
- Real discount programs: 50% off year one for startups under 2 years old and under $5M raised, org-size non-profit discounts, a $100 credit for open-source companies, free for students
Cons
- Narrowest scope: its own pricing page rates its tracing, UI, experiments and evaluation as limited or average against the other four
- 7-day retention on Hobby and only 1 month on Pro, with 3 months on the $799 Team plan
- Ingest ceilings are low by comparison - 10 logs/min on Hobby against 1,000 on Pro and 30,000 on Enterprise
Pricing verified 2026-10-03
Frequently asked questions
Which is better overall, LangSmith or Helicone?
LangSmith is our overall pick (4.4/5 vs 3.8/5). Helicone installs in one line and prices per request ($79/mo Pro); LangSmith gives full agent trace trees, evaluation and deployment at $39/seat plus usage.
Do LangSmith and Helicone offer free plans?
LangSmith and Helicone have a free tier. LangSmith paid plans start at $39/seat/mo (Plus); Helicone paid plans start at $79/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.