# Alternatives to Arize Phoenix

Phoenix is an open-source observability and evaluation library from Arize AI for tracing, evaluating, and troubleshooting LLM applications, built on OpenTelemetry.

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.

Source: https://altcatalog.com/alternatives/arize-phoenix/
Category: AI evaluation platforms

## Overview

- **Who it's for**: 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.
- **What you get**: 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.
- **How it works**: 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.

## Profile

- **License**: Elastic License 2.0 (ELv2) (verified 2026-07-17)
- **Pricing model**: Free (verified 2026-07-17)
- **Starts at**: Free (verified 2026-07-17)
- **Platforms**: Web
- **Status**: active (verified 2026-07-17)

## Ranked alternatives

| # | App | Alt Score | Licence | Platforms |
|---|-----|-----------|---------|-----------|
| 1 | [Comet Opik](https://altcatalog.com/alternatives/comet-opik.md) | 100 | Apache-2.0 | Web |
| 2 | [Langfuse](https://altcatalog.com/alternatives/langfuse.md) | 100 | MIT | Web |
| 3 | [Braintrust](https://altcatalog.com/alternatives/braintrust.md) | 96 | Proprietary (platform); MIT (autoevals library) | Web |
| 4 | [HoneyHive](https://altcatalog.com/alternatives/honeyhive.md) | 93 | Proprietary | Web |
| 5 | [LangSmith](https://altcatalog.com/alternatives/langsmith.md) | 93 | Proprietary (platform); MIT (client SDK) | Web |
| 6 | [W&B Weave](https://altcatalog.com/alternatives/wandb-weave.md) | 93 | Apache-2.0 | Web |
| 7 | [Helicone](https://altcatalog.com/alternatives/helicone.md) | 76 | Apache License 2.0 | Web |

Alt Score = Verified coverage (90%) + Visibility (10%). See https://altcatalog.com/how-alt-score-works/

## Feature comparison

Legend: Yes / No / Partial / ? (not verified).

| AI evaluation platforms checklist | Arize Phoenix | Comet Opik | Langfuse | Braintrust | HoneyHive | LangSmith |
|---|---|---|---|---|---|---|
| Pricing model | Free | OSS + paid hosting | OSS + paid hosting | Freemium | Freemium | Freemium |
| Starts at | Free | $19/month (USD) | $29/month (USD) | $249/month | Free | $39/seat/mo |
| License | Elastic License 2.0 (ELv2) | Apache-2.0 | MIT | Proprietary (platform); MIT (autoevals library) | Proprietary | Proprietary (platform); MIT (client SDK) |
| Platforms | Web | Web | Web | Web | Web | Web |
| Open source | Partial | Yes | Yes | Partial | No | No |
| Self-hostable | Yes | Yes | Yes | Yes | Yes | Yes |
| Tracing / observability | Yes | Yes | Yes | Yes | Yes | Yes |
| Prompt playground & versioning | Yes | Yes | Yes | Yes | Yes | Yes |
| Dataset management | Yes | Yes | Yes | Yes | Yes | Yes |
| LLM-as-judge evals | Yes | Yes | Yes | Yes | Yes | Yes |
| Human annotation / review | Yes | Yes | Yes | Yes | Yes | Yes |
| Online (production) monitoring | Yes | Yes | Yes | Yes | Yes | Yes |
| A/B experiments | Yes | Yes | Yes | Yes | Yes | Yes |
| CI / regression testing | Yes | Yes | Yes | Yes | Yes | Yes |
| Cost & token tracking | Yes | Yes | Yes | Yes | Yes | Yes |
| Framework-agnostic SDK | Yes | Yes | Yes | Yes | Yes | Yes |
| Free tier | Yes | Yes | Yes | Yes | Yes | Yes |

## Sources

Sources for Arize Phoenix. Each alternative is sourced on its own page.

- **License**: Elastic License 2.0 (ELv2) — <https://raw.githubusercontent.com/Arize-ai/phoenix/main/LICENSE> (verified 2026-07-17)
  - Quote: “Elastic License 2.0 (ELv2)”
- **Pricing model**: Free — <https://arize.com/docs/phoenix/self-hosting> (verified 2026-07-17)
  - Note: 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
  - Quote: “Phoenix is **free to self-host** with no feature limitations.”
- **Starts at**: Free — <https://arize.com/docs/phoenix/self-hosting> (verified 2026-07-17)
  - Quote: “100% Free ... No license fees, no usage limits, no feature gates”
- **Platforms**: Web — <https://arize.com/docs/phoenix/phoenix-cloud> (verified 2026-07-17)
  - Note: Phoenix is a self-hosted or cloud-hosted web application (plus Python/TypeScript SDKs); no native desktop or mobile clients.
  - Quote: “Click the “Create a Space” button located in the upper right-hand corner of the dashboard.”
- **Status**: active — <https://arize.com/docs/phoenix/release-notes> (verified 2026-07-17)
  - Note: 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.
  - Quote: “Jump anywhere with the command palette, customize your tables, and script configuration from a credentials file.”
- **Open source**: Partial — <https://raw.githubusercontent.com/Arize-ai/phoenix/main/LICENSE> (verified 2026-07-17)
  - Note: 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
  - Quote: “Elastic License 2.0 (ELv2)”
- **Self-hostable**: Yes — <https://arize.com/docs/phoenix/self-hosting> (verified 2026-07-17)
  - Quote: “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.”
- **Tracing / observability**: Yes — <https://arize.com/docs/phoenix/tracing/llm-traces> (verified 2026-07-17)
  - Quote: “Phoenix traces AI applications, via OpenTelemetry and has first-class integrations with LlamaIndex, LangChain, OpenAI, and others.”
- **Prompt playground & versioning**: Yes — <https://arize.com/docs/phoenix/prompt-engineering/overview-prompts/prompt-management> (verified 2026-07-17)
  - Quote: “Versioning: Track changes over time to ensure that the best performing version is deployed for use in your application.”
- **Dataset management**: Yes — <https://arize.com/docs/phoenix/datasets-and-experiments/overview-datasets> (verified 2026-07-17)
  - Quote: “Datasets are integral to evaluation. They are collections of examples that provide the `inputs` and, optionally, expected `reference` outputs for assessing your application.”
- **LLM-as-judge evals**: Yes — <https://arize.com/docs/phoenix/evaluation/llm-evals> (verified 2026-07-17)
  - Quote: “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.”
- **Human annotation / review**: Yes — <https://arize.com/docs/phoenix/tracing/how-to-tracing/feedback-and-annotations/annotating-in-the-ui> (verified 2026-07-17)
  - Quote: “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”
- **Online (production) monitoring**: Yes — <https://arize.com/docs/phoenix/evaluation/llm-evals> (verified 2026-07-17)
  - Note: 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.
  - Quote: “You can run evaluations on traces from production, on experiment results, or on any dataset.”
- **A/B experiments**: Yes — <https://arize.com/docs/phoenix> (verified 2026-07-17)
  - Quote: “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”
- **CI / regression testing**: Yes — <https://arize.com/docs/phoenix/evaluation/integrations/pytest> (verified 2026-07-17)
  - Quote: “Write LLM evaluations as ordinary pytest tests that run in CI and record results to Phoenix.”
- **Cost & token tracking**: Yes — <https://arize.com/docs/phoenix/tracing/how-to-tracing/cost-tracking> (verified 2026-07-17)
  - Quote: “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”
- **Framework-agnostic SDK**: Yes — <https://raw.githubusercontent.com/Arize-ai/phoenix/main/README.md> (verified 2026-07-17)
  - Quote: “Phoenix is vendor and language agnostic with out-of-the-box support for popular frameworks”
- **Free tier**: Yes — <https://arize.com/docs/phoenix/environments> (verified 2026-07-17)
  - Quote: “Phoenix Cloud provides free-to-use Phoenix instances that are preconfigured for you with 10GBs of storage space.”

---
Ranked by verified data, never by who paid. https://altcatalog.com/trust/