Alternatives to Arize Phoenix
Open-source LLM tracing and evaluation from Arize AI.
Arize Phoenix ranks #3 of 8 in AI evaluation platforms, with an Alt Score of 96. It is licensed under Elastic License 2.0 (ELv2), free from Free and available on the web. 13 of 13 checklist rows are verified against a public source.
Phoenix is an open-source observability and evaluation library from Arize AI for tracing, evaluating, and troubleshooting LLM applications, built on OpenTelemetry.
AI engineers and teams building LLM applications and agents who need to trace, evaluate, and debug their systems in development or production — from individual developers self-hosting for free to teams needing full data control or air-gapped deployments.
Tracing built on OpenTelemetry, LLM-as-judge and code-based evaluations, a prompt playground with prompt versioning, dataset management, and experiment comparison, plus token cost tracking and human annotation tools — delivered as a source-available (Elastic License 2.0) platform that is free to self-host with no feature gates, or usable via a free Phoenix Cloud instance with 10 GiB of storage.
You instrument your application with OpenTelemetry/OpenInference to send traces to a Phoenix instance (self-hosted via Docker, Kubernetes/Helm, or run in Phoenix Cloud), then use the web UI or the Python/TypeScript SDK to run evaluations on those traces, annotate them, manage and test prompt versions, and run experiments against datasets — including gating changes in CI with the pytest integration.
Why people leave Arize Phoenix
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Ranked alternatives
Ordered by Alt Score. Click any score to see the breakdown.
Opik is an open-source LLM evaluation platform from Comet for tracing, evaluating, and monitoring LLM applications, with datasets, LLM-as-judge metrics, and a prompt playground.
Langfuse is an open-source LLM engineering platform providing tracing, prompt management, evaluations, datasets, and analytics for LLM applications; self-hostable or cloud.
Braintrust is an evaluation and observability platform for AI products, with datasets, LLM-as-judge scorers, prompt playground, and production logging.
HoneyHive is an AI evaluation and observability platform for testing, tracing, and monitoring LLM applications, with datasets, LLM-as-judge evaluators, and human review.
LangSmith is a platform for debugging, testing, evaluating, and monitoring LLM applications, with tracing, datasets, and LLM-as-judge evaluations.
Weave is the Weights & Biases toolkit for tracking, evaluating, and monitoring LLM applications, with tracing, scorers, and experiment comparison.
Feature comparison
Rows come from the AI evaluation platforms checklist (17 rows). Human-verified cells only. ? means the value has not been verified.
| AI evaluation platforms checklist | Arize Phoenix | Comet Opik | Langfuse | Braintrust | HoneyHive | LangSmith |
|---|---|---|---|---|---|---|
| Pricing model | ||||||
| Starts at | ||||||
| License | ||||||
| Platforms | ||||||
| Open source | ||||||
| Self-hostable | ||||||
| Tracing / observability | ||||||
| Prompt playground & versioning | ||||||
| Dataset management | ||||||
| LLM-as-judge evals | ||||||
| Human annotation / review | ||||||
| Online (production) monitoring | ||||||
| A/B experiments | ||||||
| CI / regression testing | ||||||
| Cost & token tracking | ||||||
| Framework-agnostic SDK | ||||||
| Free tier |
Every fact and feature listed for Arize Phoenix is verified against its own pages. Each alternative is sourced on its own page.
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License Elastic License 2.0 (ELv2) verified 2026-07-17
Elastic License 2.0 (ELv2)
https://raw.githubusercontent.com/Arize-ai/phoenix/main/LICENSE -
Pricing model Free verified 2026-07-17
Self-hosting Phoenix is fully free with no feature gates; Phoenix Cloud (the hosted option) is also free with 10 GiB storage per docs/phoenix/environments. No paid Phoenix-specific tier was found — th
Phoenix is **free to self-host** with no feature limitations.
https://arize.com/docs/phoenix/self-hosting -
Starts at Free verified 2026-07-17
100% Free ... No license fees, no usage limits, no feature gates
https://arize.com/docs/phoenix/self-hosting -
Platforms Web verified 2026-07-17
Phoenix is a self-hosted or cloud-hosted web application (plus Python/TypeScript SDKs); no native desktop or mobile clients.
Click the “Create a Space” button located in the upper right-hand corner of the dashboard.
https://arize.com/docs/phoenix/phoenix-cloud -
Status active verified 2026-07-17
Dated 07.14.2026 release entry (three days before research date); GitHub shows arize-phoenix-v18.1.0 published same week, indicating an actively maintained project.
Jump anywhere with the command palette, customize your tables, and script configuration from a credentials file.
https://arize.com/docs/phoenix/release-notes -
Open source Partial verified 2026-07-17
Source-available under the Elastic License 2.0, which is NOT an OSI-approved open-source license (it restricts offering the software as a hosted/managed service to third parties). Code is public and f
Elastic License 2.0 (ELv2)
https://raw.githubusercontent.com/Arize-ai/phoenix/main/LICENSE -
Self-hostable Yes verified 2026-07-17
Phoenix is **free to self-host** with no feature limitations. Your data stays entirely within your infrastructure—nothing is sent to Arize and can be fully air-gapped.
https://arize.com/docs/phoenix/self-hosting -
Tracing / observability Yes verified 2026-07-17
Phoenix traces AI applications, via OpenTelemetry and has first-class integrations with LlamaIndex, LangChain, OpenAI, and others.
https://arize.com/docs/phoenix/tracing/llm-traces -
Prompt playground & versioning Yes verified 2026-07-17
Versioning: Track changes over time to ensure that the best performing version is deployed for use in your application.
https://arize.com/docs/phoenix/prompt-engineering/overview-prompts/prompt-management -
Dataset management Yes verified 2026-07-17
Datasets are integral to evaluation. They are collections of examples that provide the `inputs` and, optionally, expected `reference` outputs for assessing your application.
https://arize.com/docs/phoenix/datasets-and-experiments/overview-datasets -
LLM-as-judge evals Yes verified 2026-07-17
Phoenix supports both deterministic code-based evaluators (exact match, regex, custom heuristics) and LLM-as-a-judge evaluators, where a second model scores the output against a rubric.
https://arize.com/docs/phoenix/evaluation/llm-evals -
Human annotation / review Yes verified 2026-07-17
Once you have annotations configured, you can associate annotations to the data that you have traced. Click on the `Annotate` button and fill out the form to rate different steps in your AI applicatio
https://arize.com/docs/phoenix/tracing/how-to-tracing/feedback-and-annotations/annotating-in-the-ui -
Online (production) monitoring Yes verified 2026-07-17
Phoenix ingests and evaluates production traffic; continuous alerting with threshold-based triggers is called out on the same page as an Arize AX (paid) capability, not part of OSS Phoenix.
You can run evaluations on traces from production, on experiment results, or on any dataset.
https://arize.com/docs/phoenix/evaluation/llm-evals -
A/B experiments Yes verified 2026-07-17
Datasets & Experiments help you test changes systematically using the same inputs. You can group traces into datasets, rerun them through different versions of your application, and compare evaluation
https://arize.com/docs/phoenix -
CI / regression testing Yes verified 2026-07-17
Write LLM evaluations as ordinary pytest tests that run in CI and record results to Phoenix.
https://arize.com/docs/phoenix/evaluation/integrations/pytest -
Cost & token tracking Yes verified 2026-07-17
Phoenix allows you to track token-based costs for LLM runs automatically. The costs are calculated from token counts and model pricing data, then rolled up to the trace and project level for comprehen
https://arize.com/docs/phoenix/tracing/how-to-tracing/cost-tracking -
Framework-agnostic SDK Yes verified 2026-07-17
Phoenix is vendor and language agnostic with out-of-the-box support for popular frameworks
https://raw.githubusercontent.com/Arize-ai/phoenix/main/README.md -
Free tier Yes verified 2026-07-17
Phoenix Cloud provides free-to-use Phoenix instances that are preconfigured for you with 10GBs of storage space.
https://arize.com/docs/phoenix/environments
FAQ
Yes. Braintrust, HoneyHive and LangSmith have a free tier or are fully free. Free-tier limits in the comparison table are verified and dated.
Comet Opik, Langfuse and Braintrust — every license claim links its source.