LLMOps and observability
Arize Phoenix: review, pricing, data and alternatives
Arize Phoenix lets teams developing agents examine execution steps and evaluate response quality. It also supports comparing prompt versions and building datasets to use when testing their systems. A free tier exists. Access and transparency score: 81/100, #4 of 18 in its category.
| Access | 15/30 | |
|---|---|---|
| Openness | 30/30 | |
| Trust | 36/40 |
What is Arize Phoenix?
Arize Phoenix lets teams developing agents examine execution steps and evaluate response quality. It also supports comparing prompt versions and building datasets to use when testing their systems.
According to its documentation, Arize Phoenix lets you:
- examine an agent’s execution steps
- evaluate response quality
- compare multiple versions of a prompt
- build datasets for testing
We file it under LLMOps and observability, the category of tools to evaluate, monitor and debug AI apps, and it also overlaps with developer tools. The category lists 18 verified tools on this site.
The publisher is Arize AI, Inc.. The service launched in 2023, which gives it some track record.
Who is it for?
It is mostly useful to these profiles: developers, data analysts, and researchers. The need it covers is simple to state: evaluate, monitor and debug AI apps.
Arize Phoenix is a good candidate if:
- you want to try before paying
- you plan to connect it to your tools or automations through its API
- you must keep your data in Europe or on your own machine
- you want to read the code or host it yourself
Before deciding, run a trial on a real task and measure the time saved: it is the only criterion that really counts.
How much does Arize Phoenix cost?
Pricing model: open source (public code). Basic use costs nothing.
To estimate what the same work would cost done directly with an AI model, use our API price calculator. Prices change often: always check the official site before subscribing.
Data and privacy
According to its privacy policy, data is processed on your device (local processing).
Local processing is the most favourable case: your files do not leave your machine for the features concerned.
Exporting your content: yes (details on the official site). Being able to get your data back makes switching tools easier later.
Three habits apply to every AI tool:
- turn off the use of your content for training if the option exists
- use a work account separate from your personal account
- review everything the tool produces before publishing or sending it
Platforms, languages and API
Arize Phoenix runs on: web browser and API.
Interface languages: English.
A public API lets you call it from your own programs or an automation tool, and plug it into an AI agent.
The source code is public: Arize-aiArize-ai/phoenix.
How we scored it
Our 81/100 score does not judge output quality: it measures what can be publicly verified about access to the tool, its openness and how far the publisher can be trusted.
| Criterion | Points | What counts |
|---|---|---|
| Access | 15/30 | free tier, published price, French interface |
| Openness | 30/30 | API, data export, open code |
| Trust | 36/40 | identified publisher, declared hosting, age, presence in reference lists |
The full calculation is explained on our method page.
Comparison with alternatives
Arize Phoenix against other tools in the lLMOps and observability category:
| Tool | Free | Entry price | API | Score |
|---|---|---|---|---|
| Arize Phoenix | Yes | not published | Yes | 81 |
| Langfuse | Yes | $29 per month | Yes | 95 |
| LangSmith | Yes | $39 per month | Yes | 85 |
| Opik | Yes | $19 per month | Yes | 83 |
| Overmind | Yes | $120 per month | Yes | 78 |
| MLflow | Yes | not published | Yes | 78 |
| Respan | Yes | $199 per month | Yes | 71 |
| Prisma AIRS AI Gateway — Portkey | Yes | $49 per month | Yes | 71 |
Verdict
Arize Phoenix is among the most accessible and transparent tools in its category.
Strengths
- Free tier to try it
- Public API
- Public source code
- Local processing available
- Established since 2023
Alternatives
Categories and jobs
Learn more
Frequently asked questions
Is Arize Phoenix free?
Yes, a free plan exists, with usage limits.
Where is Arize Phoenix data stored?
According to the publisher, on your device (local processing).
Does Arize Phoenix have an API?
Yes, a public API is documented.
What are the alternatives to Arize Phoenix?
In the same category: Langfuse, LangSmith, Opik, and Overmind.
Arize Phoenix or Langfuse: which one to choose?
Our score is 81/100 for Arize Phoenix and 95/100 for Langfuse. Try both on the same task before paying.
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Neutrality. No affiliate links. No vendor pays to be reviewed, rated or ranked. Reviews are directed by François Chollet, neutral and factual, and every data point is dated and sourced. How we score