kitio.aiArize AI vs Evidently AI
A side-by-side look at pricing plans, free tiers, features, pros and cons, updated for 2026. Arize AI starts at $50/mo and Evidently AI starts at See pricing page. Check both pricing pages for current plans.
At a glance
Best for
Category
Pricing model
Starting price
Free plan
Made by
Based in
Rating
Key features
- Arize Phoenix open source
- Agent tracing
- Online evaluations
- Drift monitoring
- Debugging copilot
- Built-in metric presets
- Data drift detection
- LLM-as-judge evals
- Interactive reports
- Cloud dashboards
| Feature | Arize AI | Evidently AI |
|---|---|---|
| Best for | AI observability and evaluation, plus the open-source Phoenix | Open-source evaluation and monitoring for ML models and LLM apps |
| Category | Models & APIs | Models & APIs |
| Pricing model | Freemium | Freemium |
| Starting price | $50/mo | See pricing page |
| Free plan | Yes | Yes |
| Made by | Arize AI | Evidently AI |
| Based in | United States | – |
| Rating | No ratings yet | No ratings yet |
| Key features |
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Pricing compared
Arize AI starts at $50/mo and Evidently AI starts at See pricing page. Check both pricing pages for current plans.
Free plan
Cheapest paid plan
Top plan
Free trial
3 plans
AX Free
Free
- 25k spans/month
- 1 GB ingestion/month
- 15 days retention
- Unlimited users
AX Pro
$50/mo
- 50k spans/month
- 10 GB ingestion/month
- 30 days retention
AX Enterprise
Contact sales
- Custom plans
Prices in USD, checked Oct 28, 2026 or later. Plans change often, so confirm on each tool's site before you buy.
Pros and cons
Arize AI
- Free open-source Phoenix
- Covers classic ML and LLMs
- Strong enterprise features
- AX costs rise with volume
- Two products can confuse
- Steeper setup than simple tools
Evidently AI
- Covers classic ML and LLMs
- Free open-source core
- Many ready-made tests
- Python-only library
- Cloud needed for team features
- Less agent tracing depth
Which one should you choose?
Choose Arize AI if you want:
- Free open-source Phoenix
- Covers classic ML and LLMs
- Strong enterprise features
Watch out: ax costs rise with volume.
Choose Evidently AI if you want:
- Covers classic ML and LLMs
- Free open-source core
- Many ready-made tests
Watch out: python-only library.
Arize AI vs Evidently AI FAQ
What is the difference between Arize AI and Evidently AI?
Arize AI: AI observability and evaluation, plus the open-source Phoenix. Evidently AI: Open-source evaluation and monitoring for ML models and LLM apps. Both are models & apis tools.
Is Arize AI or Evidently AI cheaper?
Arize AI starts at $50/mo and Evidently AI starts at See pricing page. Check both pricing pages for current plans.
Do Arize AI and Evidently AI have free plans?
Arize AI: Yes. Evidently AI: Yes.
Who makes Arize AI?
Arize AI is made by Arize AI, based in United States.
Who makes Evidently AI?
Evidently AI is made by Evidently AI.
Which should I choose, Arize AI or Evidently AI?
Choose Arize AI if you value free open-source phoenix and covers classic ml and llms. Choose Evidently AI if you value covers classic ml and llms and free open-source core.