Suggestions appear as you type. Use the up and down arrows to choose one and Enter to open it.

This page's audience our own tag's counts — open to see them
–Visits
–Page views
–Clicks to vendors
–Time on page
–Reading now
Clicks to vendors, by tool
  • –
Top countries
  • –
Devices
  • –

– · visits, page views and clicks counted by our own tag, which counts more than our checked analytics; every figure rounded down · how we count

Head-to-head · AI LLM Evaluation Tools

Arize Phoenix vs Promptfoo

  • Updated Oct 2026
  • Both researched from official sources
  • 1 check side by side
Higher score Arize Phoenix #2 in AI LLM Evaluation Tools 9.3/10 Free plan Free plan✓ 0 of 3 features Visit Arize Phoenix
Promptfoo #3 in AI LLM Evaluation Tools 9.2/10 Free plan Free plan✓ 0 of 3 features Visit Promptfoo

Arize Phoenix leads on 0 checks, Promptfoo on 0, and 1 is even. Who comes out ahead on the 1 yes/no, price and count check where we have data for both products. The editor score weighs everything else too.

Our verdict

  • Highest scoreArize Phoenix · 9.3/10
  • Free planboth

Arize Phoenix scores higher on our rubric for ai llm evaluation tools: 9.3 against 9.2 out of 10; our editors rank them #2 and #3.

Arize Phoenix is the better fit for teams wanting broad open-source evaluation observability. Promptfoo is the better fit for teams prioritizing testing and red teaming.

  • Arize Phoenix fits best

    Teams wanting broad open-source evaluation observability

  • Promptfoo fits best

    Teams prioritizing testing and red teaming

Advertiser disclosure: iTechGuides is reader-supported. Vendors can pay for top positions in our rankings and for a place on other products' pages, and we may earn a commission when you click some links. Bought places stand at the number bought; this page and our disclosure say so. Paying vendors may get a fuller, more detailed review from our editors, and that review can change their score. How we rank.

Side by side

Feature Arize Phoenix 9.3/10 Visit ↗ Promptfoo 9.2/10 Visit ↗
At a glance
Editor score 9.3 9.2
Ranking #2 in AI LLM Evaluation Tools #3 in AI LLM Evaluation Tools
Best for Teams wanting broad open-source evaluation observability Teams prioritizing testing and red teaming
Pricing model Free Free plan + paid
Starting price Free —
Free plan ✓ ✓
Free trial — —
Deployment Cloud, Self-hosted Cloud, Self-hosted
Platforms Web Web
Support Community, Docs Community, Docs
Integrations 11 integrations 12 integrations
Built for Solo, Small business, Mid-market, Enterprise Solo, Small business, Mid-market, Enterprise
Features Arize Phoenix 0/3 · Promptfoo 0/3
Safety evaluations Not checked yet Not checked yet
Prompt versioning Not checked yet Not checked yet
API access Not checked yet Not checked yet
Specs
Evaluation methods Not checked yet Not checked yet
Model support Not checked yet Not checked yet
Deployment Not checked yet Not checked yet
Our review
Pros
  • Free, open-source platform with local and self-hosted deployment
  • Traces model calls, retrieval, tool use, and custom application logic
  • Combines evaluations, prompts, datasets, experiments, and cost tracking
  • Evaluates prompts, models, RAG pipelines, safety, and vulnerabilities
  • Supports custom metrics, human review, and LLM-as-a-judge grading
  • Connects with major providers, CI tools, observability, and MCP
Cons
  • Requires instrumentation through OpenTelemetry or OpenInference
  • Its wide feature set may exceed the needs of narrow evaluation workflows
  • The listed Phoenix plan does not offer tiered pricing or feature levels
  • Enterprise and On-Premise plans use custom pricing
  • Team collaboration and continuous monitoring require Enterprise
  • Dedicated deployment engineering is limited to On-Premise
Our verdict

Arize Phoenix is an open-source observability and evaluation platform for AI applications and agents. It is designed for teams that need to inspect model calls, retrieval, tool use, and custom logic while evaluating application quality.…

Read the review →

Promptfoo is an open-source CLI and library for evaluating, testing, and red-teaming large-language-model applications. It is designed for teams benchmarking prompts, models, and RAG pipelines, as well as developers checking AI quality,…

Read the review →
  1. Arize PhoenixAI LLM Evaluation Tools 9.3Free plan
  2. PromptfooAI LLM Evaluation Tools 9.2Free plan

Strengths and trade-offs

  • Arize Phoenix — where it wins

    • Free, open-source platform with local and self-hosted deployment
    • Traces model calls, retrieval, tool use, and custom application logic
    • Combines evaluations, prompts, datasets, experiments, and cost tracking

    Where it doesn't

    • Requires instrumentation through OpenTelemetry or OpenInference
    • Its wide feature set may exceed the needs of narrow evaluation workflows
    • The listed Phoenix plan does not offer tiered pricing or feature levels

  • Promptfoo — where it wins

    • Evaluates prompts, models, RAG pipelines, safety, and vulnerabilities
    • Supports custom metrics, human review, and LLM-as-a-judge grading
    • Connects with major providers, CI tools, observability, and MCP

    Where it doesn't

    • Enterprise and On-Premise plans use custom pricing
    • Team collaboration and continuous monitoring require Enterprise
    • Dedicated deployment engineering is limited to On-Premise

More comparisons

All AI LLM evaluation tools comparisons → · Full ranking →

Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026

Last updated · How we research and update