Langfuse alternatives
Prices checked 2026-10-17 on each vendor's own pricing page.
Short answer: For another open-source, self-hostable platform, look at Comet Opik, Helicone or Arize Phoenix. For a hosted platform, Braintrust, LangSmith, Confident AI, Maxim, W&B Weave and Splunk Agent Observability (Galileo) cover similar ground with different meters. For tests in CI only, Promptfoo or Ragas.
For reference, Langfuse: free tier: Hobby: 50k units/month, 30 days data access, 2 users [source, checked 2026-10-17]; entry paid: Core $29/month: 100k units included, then $8 per 100k units (graduated down to $6 per 100k above 50M) [source, checked 2026-10-17]
Open source and self-hostable
Code you can run on your own infrastructure.
| Tool | Best for | Licence | Free tier | Entry paid price |
|---|---|---|---|---|
| Arize AX and Phoenix | Teams that want an OpenTelemetry-native stack: Phoenix to self-host for free, Arize AX when they want a managed service. | Phoenix: Elastic License 2.0. Arize AX: hosted service [source] | AX Free: 25k spans/month, 1 GB ingestion, 15-day retention, unlimited users [source, checked 2026-10-17] | AX Pro $50/month: 50k spans, 10 GB, 30-day retention (overage rates not stated on the pricing page) [source, checked 2026-10-17] |
| Helicone | Teams that want request logging, cost tracking and a gateway first, with scores and datasets on top. | Apache-2.0 [source] | Hobby: 10,000 requests/month, 1 GB storage, 1 seat, 7-day retention [source, checked 2026-10-17] | Pro $79/month plus usage-based pricing (usage rates are shown only via a calculator, not verified) [source, checked 2026-10-17] |
| Comet Opik | Teams that want a fully open-source tracing and evaluation platform with a low-cost cloud option. | Apache-2.0 [source] | Free Cloud: 25k spans/month, up to 10 team members, 60-day retention; open source self-hosted is free [source, checked 2026-10-17] | Pro Cloud $19/month: 100k spans, up to 50 members, then $5 per 100k spans [source, checked 2026-10-17] |
Hosted platforms
Managed services; self-hosting, where offered, is on Enterprise plans.
| Tool | Best for | Licence | Free tier | Entry paid price |
|---|---|---|---|---|
| Braintrust | Product and engineering teams that run many experiments and want evals, human review and prompt playgrounds in one hosted tool. | Hosted service; its autoevals scorer library is MIT [source] | Starter $0: 1 GB processed data, 10k scores, 14-day retention, unlimited users; then $4/GB and $2.50 per 1k scores [source, checked 2026-10-17] | Pro $249/month: 5 GB and 50k scores included, then $3/GB and $1.50 per 1k scores; 30-day retention [source, checked 2026-10-17] |
| LangSmith | Teams building on LangChain or LangGraph that want tracing, evals and agent deployment from the same vendor. | Hosted service; self-hosted and hybrid options on Enterprise [source] | Developer $0: 1 seat, up to 5k base traces/month, then pay as you go [source, checked 2026-10-17] | Plus $39/seat/month: up to 10k base traces/month, then pay as you go (per-trace rate not stated on the pricing page) [source, checked 2026-10-17] |
| DeepEval and Confident AI | Python teams that want pytest-style LLM tests with ready-made RAG and agent metrics, with an optional hosted platform. | DeepEval: Apache-2.0. Confident AI: hosted service [source] | Free: 2 seats, 1 project, 5 test runs/week, 1 GB-month of trace spans [source, checked 2026-10-17] | Starter $200/month per organization: unlimited seats, 5 projects, 5 GB-months, then $1 per GB-month [source, checked 2026-10-17] |
| Galileo (Splunk Agent Observability) | Enterprises already on Splunk Observability that want agent evaluation and guardrails in the same contract. | Commercial product (Splunk) [source] | not verified | From $100/month per 1.2 million spans, billed annually; includes 500 million Luna tokens and 5 Luna fine-tuning runs per year [source, checked 2026-10-17] |
| Maxim AI | Teams testing agents with simulations and wanting experimentation, evals and observability priced per seat. | Platform is a hosted service; Bifrost gateway is Apache-2.0 [source] | Developer: free for up to 3 seats, 1 workspace, 10k logs/month, 3-day retention, no overages [source, checked 2026-10-17] | Professional $29/seat/month: 100k logs/month, 7-day retention, $1 per 10k extra logs [source, checked 2026-10-17] |
| W&B Weave | Teams already using W&B for model training that want LLM tracing and evals in the same account. | Weave SDK: Apache-2.0; the platform is a hosted service [source] | Free $0: 1 GB/month Weave data ingestion [source, checked 2026-10-17] | Pro from $60/month: 1.5 GB/month ingestion, then $0.10 per MB; for teams under 50 employees [source, checked 2026-10-17] |
Frameworks for tests in CI
Libraries and CLIs rather than full platforms.
| Tool | Best for | Licence | Free tier | Entry paid price |
|---|---|---|---|---|
| Promptfoo | Developers who want config-driven prompt and model tests plus red-teaming that run locally and in CI. | MIT [source] | Community: free, all LLM evaluation features, red teaming up to 10k probes/month [source, checked 2026-10-17] | Enterprise: custom pricing (no public price) [source, checked 2026-10-17] |
| Ragas | Teams that need RAG and agent metrics as a Python library inside their own pipeline or another platform. | Apache-2.0 [source] | Free, open source [source, checked 2026-10-17] | No paid plan published [source, checked 2026-10-17] |
Head-to-head
- Braintrust vs Langfuse
- Langfuse vs LangSmith
- Arize Phoenix vs Langfuse
- Comet Opik vs Langfuse
- All 12 platforms, full feature table
- Pricing calculator
Other alternatives pages: LangSmith alternatives · Braintrust alternatives · Arize AX and Phoenix alternatives
FAQ
What is the best open-source alternative to Langfuse?
There is no single best one. Comet Opik (Apache-2.0) and Helicone (Apache-2.0) are open source and self-hostable; Arize Phoenix is self-hostable under the Elastic License 2.0. Opik covers the most similar feature list (tracing, test suites, annotation, prompt versioning); Helicone starts from request logging and a gateway.
Is there a cheaper alternative to Langfuse?
On published entry prices checked 17 Oct 2026, Comet Opik Pro Cloud is $19/month against Langfuse Core at $29/month. Opik counts spans and Langfuse counts units, so compare on your own volume in the pricing calculator.
Why look for a Langfuse alternative?
Common reasons are a preference for a vendor already in the stack (LangChain, W&B, Splunk), per-seat versus usage pricing, or wanting a pure CI test framework instead of a platform.