LLM Observability Cost Comparison
Enter one workload — requests per month, spans per request, KB per trace and scores. The table prices it on Langfuse Core and Pro (billed by units, i.e. event count) and Braintrust Starter and Pro (billed by GB processed), plus LangSmith and Helicone plan prices for reference. The cheaper option flips with trace size. Estimates only; provider pricing pages prevail.
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| Option | Monthly | $ / 1k requests | Note |
|---|
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Langfuse bills by units (event count: traces + observations + scores, 100k included, then $8→$6 per 100k graduated) while Braintrust bills by GB processed ($4 Starter / $3 Pro per GB) plus scores — so the cheaper option flips with trace size. LangSmith (Developer $0 with 5k base traces, Plus $39/seat with 10k) and Helicone (Hobby free 10k requests / 1 GB, Pro $79, Team $799) are shown as plan prices only because their usage overage is not published as a fixed rate. Retention: Langfuse Core 90 days / Pro 3 years; Braintrust Starter 14 / Pro 30 days.
Estimates only. Official list prices as of 2026-11-02 (Asia/Shanghai); the provider's pricing page prevails. Sources: Langfuse pricing · Braintrust pricing · LangSmith pricing · Helicone pricing
Langfuse Cost Calculator · Braintrust Cost Calculator · LLM API Cost Calculator · AI Agent Cost Calculator · RAG Cost Calculator · LLM Prompt Caching Cost Calculator
More in this group
- Langfuse Cost Calculator Langfuse units (traces + observations + scores) → monthly cost.
- Braintrust Cost Calculator Braintrust GB processed + scores + retention → monthly cost.
- LLM API Cost Calculator Generic token cost from any $/1M rates.
- AI Agent Cost Calculator Multi-step agent token cost per task and month.
- RAG Cost Calculator Embed + retrieve + LLM token cost in USD.
- LLM Prompt Caching Cost Calculator No-cache vs cached prompt monthly cost and savings.
- Product Analytics Cost Comparison PostHog vs Mixpanel vs Sentry monthly $.
How it works
- Is Langfuse or Braintrust cheaper?
- It depends on trace size. Langfuse bills units (event count) regardless of payload size, while Braintrust bills GB processed. Small traces with many spans favor Braintrust; large payloads with few spans favor Langfuse. The table prices both for your workload.
- Why are LangSmith and Helicone shown without usage?
- LangSmith Developer ($0, 5k base traces/month, 1 seat) and Plus ($39/seat, 10k base traces/month) do not publish per-trace overage on the pricing page, and Helicone's usage pricing (Hobby free 10k requests / 1 GB, Pro $79, Team $799) is dynamic, so only plan prices are listed.
- What counts as a Langfuse unit vs a Braintrust GB?
- A Langfuse unit is one trace, observation or score. Braintrust measures bytes processed: requests × KB per trace. Scores are billed separately on Braintrust and as units on Langfuse.
- What about retention?
- Langfuse Core gives 90-day access and Pro 3 years; Braintrust Starter 14 days and Pro 30 days with paid extension up to 180 days; LangSmith base traces keep 14 days vs 180 days for extended.
- Does this include LLM token costs?
- No. Observability is on top of model spend. Price tokens with the LLM API cost, AI agent cost, RAG cost or prompt caching calculators.