kitio.aiArthur vs Opik
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 $60 for Arthur.
At a glance
Best for
Category
Pricing model
Starting price
Free plan
Made by
Based in
Rating
Key features
- Agent discovery
- Step-level tracing
- Runtime guardrails
- Audit logs and lineage
- Custom metrics and alerts
- Tracing and spans
- Evaluation metrics
- Agent optimizer
- Guardrails
- Framework integrations
| Feature | Arthur | Opik |
|---|---|---|
| Best for | Discovery, monitoring and governance for enterprise AI agents | Comet's open-source platform for LLM tracing and evaluation |
| Category | Models & APIs | Models & APIs |
| Pricing model | Freemium | Freemium |
| Starting price | $60/mo | $19/mo |
| Free plan | Yes | Yes |
| Made by | Arthur AI | Comet |
| Based in | United States | United States |
| Rating | No ratings yet | No ratings yet |
| Key features |
|
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Pricing compared
Opik has the lower starting price: about $19 a month, against $60 for Arthur.
Free plan
Cheapest paid plan
Top plan
Free trial
3 plans
Free
Free
- Up to 4 monitored use cases
- Unlimited seats
- Cloud data connectors
Premium
$60/mo
- Up to 100 use cases
- Custom metrics and dashboards
- Custom alerts and webhooks
Enterprise
Contact sales
- Dedicated infrastructure
- Governance and support
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
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
Arthur
- Finds shadow agents across environments
- Free tier with unlimited seats
- Covers security and evaluation together
- Free tier monitors only 4 use cases
- Enterprise features need a sales call
- Broad platform takes time to set up
Opik
- Free and self-hostable
- Automatic prompt optimization
- Many integrations
- Smaller community than Langfuse
- Hosted plan limits vary
- Docs split with Comet ML
Which one should you choose?
Choose Arthur if you want:
- Finds shadow agents across environments
- Free tier with unlimited seats
- Covers security and evaluation together
Watch out: free tier monitors only 4 use cases.
Choose Opik if you want:
- Free and self-hostable
- Automatic prompt optimization
- Many integrations
Watch out: smaller community than langfuse.
Arthur vs Opik FAQ
What is the difference between Arthur and Opik?
Arthur: Discovery, monitoring and governance for enterprise AI agents. Opik: Comet's open-source platform for LLM tracing and evaluation. Both are models & apis tools.
Is Arthur or Opik cheaper?
Opik has the lower starting price: about $19 a month, against $60 for Arthur.
Do Arthur and Opik have free plans?
Arthur: Yes. Opik: Yes.
Who makes Arthur?
Arthur is made by Arthur AI, based in United States.
Who makes Opik?
Opik is made by Comet, based in United States.
Which should I choose, Arthur or Opik?
Choose Arthur if you value finds shadow agents across environments and free tier with unlimited seats. Choose Opik if you value free and self-hostable and automatic prompt optimization.