Langfuse vs Helicone vs Arize Phoenix - Top 3 LLM Observability Complete Guide 2026
Langfuse (OSS all-in-one, trace + eval + prompt + dataset, self-host free / Cloud $59-499) vs Helicone (1-line proxy + caching + cost analytics, free-$200) vs Arize Phoenix (OSS eval + enterprise Arize AX, Uber/eBay) - compare features, pricing and fit. -40% LLM cost, +90% hallucination detection, +30% eval score.
Verdict:Choose Langfuse for OSS self-host + trace/eval/prompt/dataset all-in-one. Choose Helicone for fastest proxy integration + caching savings. Choose Arize Phoenix + AX for OSS eval and production ML observability (drift/bias). Choose LangSmith for LangChain-native tracing + prompt hub. Choose Braintrust for best eval UX (Stripe/Notion/Airtable). Choose Galileo for hallucination detection focus. Choose Datadog LLM Observability for Datadog-stack shops.
Table of Contents
Langfuse & Helicone Overview
Langfuse
Germany $4M YC, 5,000+ users, Khan Academy/Twilio/SumUp/Springer Nature, OSS LLM observability leader, self-host free / Cloud $59-$499/mo, all-in-one trace + prompt + eval + dataset + playground, OpenTelemetry-compliant.
Learn more about Langfuse →Helicone
US $2M YC, 2,000+ companies, Sourcegraph/Filevine, fastest 1-line proxy integration, cost analytics + caching + rate limiting, free-$200+/mo.
Learn more about Helicone →Feature & Pricing Comparison
| Feature | Langfuse | Helicone |
|---|---|---|
| Integration | SDK (Python/JS/Java) + OpenTelemetry + manual trace API; full-instrumented | Proxy (1-line baseURL swap) + optional SDK; integrate in ~10 seconds |
| Pricing | Self-host free (MIT) / Cloud Hobby free-$59 Pro-$499 Team-Enterprise custom | Free 100K req/mo-$25 Pro-$200 Team-Enterprise |
| Eval | LLM-as-a-judge + custom metrics + datasets + experiments (best in class) | Basic eval + custom score (not eval-specialized) |
| Prompt mgmt | Prompt version control + A/B testing + production deploy (best) | Prompts can be stored but lightweight |
| Caching / cost | Trace-centric; caching not built in | Built-in caching (~90% savings on identical req) + rate limit + bucket |
| Self-host | Docker Compose + Helm chart; PostgreSQL + ClickHouse; many enterprise installs | Self-host supported (Docker) |
| Customer examples | Khan Academy / Twilio / SumUp / Springer Nature / Samsara | Sourcegraph / Filevine / Together AI |
Our Verdict
Our Verdict
Choose Langfuse for OSS self-host + trace/eval/prompt/dataset all-in-one. Choose Helicone for fastest proxy integration + caching savings. Choose Arize Phoenix + AX for OSS eval and production ML observability (drift/bias). Choose LangSmith for LangChain-native tracing + prompt hub. Choose Braintrust for best eval UX (Stripe/Notion/Airtable). Choose Galileo for hallucination detection focus. Choose Datadog LLM Observability for Datadog-stack shops.
Recommendations by Use Case
OSS all-in-one LLM obs
Khan Academy/Twilio proven, self-host free, trace + eval + prompt + dataset
Fastest proxy + caching
Sourcegraph/Filevine proven, 1-line, ~90% cache savings
Production ML + LLM
Uber/eBay/Adobe/Wayfair proven, drift/bias/eval, $30K-500K/yr
LangChain-native
Klarna/Elastic/Adyen proven, deepest LangChain integration
Best eval UX
Stripe/Notion/Airtable/Zapier proven, eval + dataset + playground
Hallucination detection
Luna eval model, faithfulness/PII focus, $30K-500K/yr
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