Langfuse vs Helicone vs LangSmith vs Arize Phoenix
A side-by-side look at scores, pricing and features — with RECATOOLS' ASEAN-aware verdict for each.
Langfuse
Open-source LLM observability, tracing and evals
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Helicone
Open-source LLM observability, now in maintenance mode
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LangSmith
LangChain's platform for tracing, evaluating and deploying agents
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Arize Phoenix
Free, self-hosted LLM tracing and evaluation
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| RECATOOLS Score | 8.4 / 10 | 7.6 / 10 | 7.9 / 10 | 7.8 / 10 |
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| Value for money | ||||
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| ASEAN readiness | ||||
| API quality | ||||
| Pricing | Freemium | Open Source | Freemium | Free |
| Free tier | Self-host free under MIT (enterprise modules need a key); cloud Hobby plan free with 50k units/month, 30 days data access, 2 users | Apache-2.0 open-source stack, free to self-host with Docker; maintenance-only updates. Hosted Hobby tier (10,000 requests/mo) is closed to new sign-ups | Developer: $0 for 1 seat with 5k base traces a month, then pay as you go | Self-host Phoenix free: no licence fees, usage limits or feature gates. Arize AX Free cloud tier: 25k spans, 1 GB ingest a month, 15-day retention |
| Paid from | $29/month (Langfuse Cloud Core) | Hosted Pro listed at $79/mo, but new sign-ups have been disabled since March 2026 | $39/seat/month (Plus, 10k base traces a month included), then usage | Phoenix is free. Arize's managed AX Pro plan is $50/month |
| Has API | ✓ | ✓ | ✓ | ✓ |
| Open source | ✓ | ✓ | ✗ | ✓ |
| Free to use | ✓ | ✓ | ✓ | ✓ |
| Users | — | — | — | — |
| Founded | 2023 | 2023 | 2023 | 2023 |
| Maker | ClickHouse, Inc. | Mintlify (acquired March 2026) | LangChain Inc. | Arize AI |
| Verdict | Langfuse covers the core of LLM observability: nested traces with cost and latency, prompt versioning, datasets, experiments and LLM-as-judge evaluators, through framework-agnostic SDKs and OpenTelemetry. The MIT core se... |
Helicone was one of the lowest-friction ways to see what your LLM calls cost. Since Mintlify acquired it in March 2026 it has been in maintenance mode, with security fixes and new-model support but no new features, and n... |
LangSmith is the most complete option for teams already on LangChain or LangGraph, where tracing works almost out of the box, and it is no longer tied to that stack: SDKs and OpenTelemetry bring in any framework. Evals,... |
Arize Phoenix is one of the most complete no-cost options for finding out why an agent or RAG pipeline behaved as it did: OpenTelemetry tracing, evals, datasets, experiments and a prompt playground, self-hosted with no f... |
| Full review → | Full review → | Full review → | Full review → |
Comparisons cover up to 4 tools. Scores are RECATOOLS editorial assessments; verify current pricing on each vendor's site.