kitio.aiArize AI vs TruLens
A side-by-side look at pricing plans, free tiers, features, pros and cons, updated for 2026. TruLens is completely free, while Arize AI is freemium.
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
- OpenTelemetry tracing
- LLM judge evaluations
- RAG triad metrics
- Custom rubrics
- Multi-turn conversation evals
| Feature | Arize AI | TruLens |
|---|---|---|
| Best for | AI observability and evaluation, plus the open-source Phoenix | Open-source evals and OpenTelemetry tracing for AI agents and RAG |
| Category | Models & APIs | Models & APIs |
| Pricing model | Freemium | Free |
| Starting price | $50/mo | Free |
| Free plan | Yes | Yes, fully free |
| Made by | Arize AI | Snowflake |
| Based in | United States | United States |
| Rating | No ratings yet | No ratings yet |
| Key features |
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Pricing compared
TruLens is completely free, while Arize AI is freemium.
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
TruLens
- Free and open source
- Judges explain each score
- Standard OpenTelemetry traces
- Python library, not a hosted product
- Judge scoring adds LLM costs
- Custom metrics require writing code
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 TruLens if you want:
- Free and open source
- Judges explain each score
- Standard OpenTelemetry traces
Watch out: python library, not a hosted product.
Arize AI vs TruLens FAQ
What is the difference between Arize AI and TruLens?
Arize AI: AI observability and evaluation, plus the open-source Phoenix. TruLens: Open-source evals and OpenTelemetry tracing for AI agents and RAG. Both are models & apis tools.
Is Arize AI or TruLens cheaper?
TruLens is completely free, while Arize AI is freemium.
Do Arize AI and TruLens have free plans?
Arize AI: Yes. TruLens: Yes, fully free.
Who makes Arize AI?
Arize AI is made by Arize AI, based in United States.
Who makes TruLens?
TruLens is made by Snowflake, based in United States.
Which should I choose, Arize AI or TruLens?
Choose Arize AI if you value free open-source phoenix and covers classic ml and llms. Choose TruLens if you value free and open source and judges explain each score.