Langfuse vs Braintrust: the honest comparison
The short answer
Edition v2026.Q3 · pricing and status verified 2026-08-06.
Choose Langfuse for the one-tool default: tracing, prompt management, LLM-as-judge evals, and datasets in a single open-source platform you can self-host in minutes or run on a $29 cloud plan. Choose Braintrust for teams that treat evals as the product-development loop itself — experiments, datasets, human review, and a purpose-built trace store (Brainstore) with the best eval workflow in the category.
On the elems table, Langfuse holds seat #1 of the Evals & Observability element and Braintrust holds #2 — this is the closest call in the category, and the honest answer depends on which trade-off you can live with.
The case for each
1LangfuseLangfuse (by ClickHouse since Jan 2026)
Hobby free (50k units/mo) · Core $29/mo · Pro $199/mo · Enterprise $2,499/mo · self-host free (MIT core)Best for The one-tool default: tracing, prompt management, LLM-as-judge evals, and datasets in a single open-source platform you can self-host in minutes or run on a $29 cloud plan.
Watch Eval UX and experiment workflows trail Braintrust's — Langfuse is observability-first, evals-second. Post-acquisition roadmap now serves ClickHouse's platform ambitions too; the /ee folders are not MIT, so 'fully open source' has an asterisk.
2BraintrustBraintrust Data
Starter free (1GB data, 10k scores) · Pro $249/mo · Enterprise custom (on-prem or hosted); 6–12 mo free for startupsBest for Teams that treat evals as the product-development loop itself — experiments, datasets, human review, and a purpose-built trace store (Brainstore) with the best eval workflow in the category.
Watch Closed source with a proprietary data store — the deepest lock-in of the top five. $249/mo Pro plus usage ($3/GB, $1.50/1k scores) makes it the priciest non-enterprise entry; the free tier's 14-day retention is the shortest here.
Langfuse vs Braintrust: side by side
Edition v2026.Q3 · verified 2026-08-06.
| Langfuse | Braintrust | |
|---|---|---|
| Entry price | Free · $29/mo | Free · $249/mo |
| Open source | Yes (MIT core) | No |
| Self-host | Yes, free | Enterprise only |
| OTel-native | Yes | Partial |
| Eval workflow | Good (judge + code + human) | Best-in-class |
| Prompt mgmt | Yes | Yes |
| Sweet spot | one-tool default | eval-driven product loops |
What each side won't tell you
Langfuse: Eval UX and experiment workflows trail Braintrust's — Langfuse is observability-first, evals-second. Post-acquisition roadmap now serves ClickHouse's platform ambitions too; the /ee folders are not MIT, so 'fully open source' has an asterisk.
Braintrust: Closed source with a proprietary data store — the deepest lock-in of the top five. $249/mo Pro plus usage ($3/GB, $1.50/1k scores) makes it the priciest non-enterprise entry; the free tier's 14-day retention is the shortest here.
If it's neither
The rest of the top five: LangSmith (the langchain-native path) · Arize Phoenix (otel-native, self-host free) · W&B Weave (agent-native, gpu-cloud backed). The complete field — 21 more tools including the graveyard — is on the element page.
This analysis is drawn from the Evals & Observability element dossier — the ranked top 5, the comparison matrix, and the complete field of 21 more tools live there, with every source. Data: ev.json (CC BY 4.0).
Every claim above is dated and sourced from the elems dossiers — 1,421 tools tracked across 58 categories, verified 2026-08-06, including the 276 we found dead, renamed, acquired, or sunsetting. Rankings are editorial, never paid — the charter.
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