kitio.aiOpik vs Arize AI
A side-by-side look at pricing plans, free tiers, features, pros and cons, updated for 2026. Opik has the lower starting price: about $19 a month, against $50 for Arize AI.
At a glance
Best for
Category
Pricing model
Starting price
Free plan
Made by
Based in
Rating
Key features
- Tracing and spans
- Evaluation metrics
- Agent optimizer
- Guardrails
- Framework integrations
- Arize Phoenix open source
- Agent tracing
- Online evaluations
- Drift monitoring
- Debugging copilot
| Feature | Opik | Arize AI |
|---|---|---|
| Best for | Comet's open-source platform for LLM tracing and evaluation | AI observability and evaluation, plus the open-source Phoenix |
| Category | Models & APIs | Models & APIs |
| Pricing model | Freemium | Freemium |
| Starting price | $19/mo | $50/mo |
| Free plan | Yes | Yes |
| Made by | Comet | Arize AI |
| Based in | United States | United States |
| Rating | No ratings yet | No ratings yet |
| Key features |
|
|
Pricing compared
Opik has the lower starting price: about $19 a month, against $50 for Arize AI.
Free plan
Cheapest paid plan
Top plan
Free trial
4 plans
Open Source
Free
- Self-hosted
- Full observability feature set
- Unlimited spans
Free Cloud
Free
- Up to 10 team members
- 25k spans per month
- 60-day data retention
Pro Cloud
$19/mo
- Up to 50 team members
- 100k spans per month
- $5 per extra 100k spans
Enterprise
Custom
- Unlimited team members
- Flexible deployments
- Single sign-on
- 2-hour response SLA
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
Opik
- Free and self-hostable
- Automatic prompt optimization
- Many integrations
- Smaller community than Langfuse
- Hosted plan limits vary
- Docs split with Comet ML
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
Which one should you choose?
Choose Opik if you want:
- Free and self-hostable
- Automatic prompt optimization
- Many integrations
Watch out: smaller community than langfuse.
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.
Opik vs Arize AI FAQ
What is the difference between Opik and Arize AI?
Opik: Comet's open-source platform for LLM tracing and evaluation. Arize AI: AI observability and evaluation, plus the open-source Phoenix. Both are models & apis tools.
Is Opik or Arize AI cheaper?
Opik has the lower starting price: about $19 a month, against $50 for Arize AI.
Do Opik and Arize AI have free plans?
Opik: Yes. Arize AI: Yes.
Who makes Opik?
Opik is made by Comet, based in United States.
Who makes Arize AI?
Arize AI is made by Arize AI, based in United States.
Which should I choose, Opik or Arize AI?
Choose Opik if you value free and self-hostable and automatic prompt optimization. Choose Arize AI if you value free open-source phoenix and covers classic ml and llms.