Arize AX and Phoenix alternatives
Prices checked 2026-10-17 on each vendor's own pricing page.
Short answer: If you like Phoenix's self-hosting, Langfuse (MIT core), Comet Opik (Apache-2.0) and Helicone (Apache-2.0) are open-source alternatives under permissive licences. For hosted plans with published overage rates, Langfuse Core ($8 per 100k units) and Comet Opik Pro Cloud ($5 per 100k spans) publish them; Arize AX Pro does not.
For reference, Arize AX and Phoenix: free tier: AX Free: 25k spans/month, 1 GB ingestion, 15-day retention, unlimited users [source, checked 2026-10-17]; entry paid: AX Pro $50/month: 50k spans, 10 GB, 30-day retention (overage rates not stated on the pricing page) [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 |
|---|---|---|---|---|
| Langfuse | Teams that want open-source, self-hostable tracing, prompt management and evals with usage-based cloud pricing. | MIT for code outside the ee/ directories; ee/ code under a separate licence [source] | Hobby: 50k units/month, 30 days data access, 2 users [source, checked 2026-10-17] | Core $29/month: 100k units included, then $8 per 100k units (graduated down to $6 per 100k above 50M) [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
Other alternatives pages: Langfuse alternatives · LangSmith alternatives · Braintrust alternatives
FAQ
What is an alternative to Arize Phoenix?
Langfuse, Comet Opik and Helicone are open source and self-hostable under MIT (Langfuse core) or Apache-2.0 licences. Phoenix uses the Elastic License 2.0, which bars offering it to third parties as a managed service.
What is an alternative to Arize AX?
Hosted alternatives with published plans include Braintrust, LangSmith, Langfuse Cloud, Comet Opik Cloud, Confident AI, Maxim and W&B Weave. Splunk Agent Observability (formerly Galileo) targets enterprises.
Which alternatives are OpenTelemetry-based?
All the hosted platforms we list document OpenTelemetry ingestion on their own pages; Helicone documents it through OpenLLMetry.