kitio.aiArthur vs PromptLayer
A side-by-side look at pricing plans, free tiers, features, pros and cons, updated for 2026. PromptLayer has the lower starting price: about $49 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
- Prompt registry
- Visual prompt editor
- Evaluation pipelines
- Request logging
- Release labels
| Feature | Arthur | PromptLayer |
|---|---|---|
| Best for | Discovery, monitoring and governance for enterprise AI agents | Prompt management and evals for teams where non-engineers edit prompts |
| Category | Models & APIs | Models & APIs |
| Pricing model | Freemium | Freemium |
| Starting price | $60/mo | $49/mo |
| Free plan | Yes | Yes |
| Made by | Arthur AI | PromptLayer |
| Based in | United States | United States |
| Rating | No ratings yet | No ratings yet |
| Key features |
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Pricing compared
PromptLayer has the lower starting price: about $49 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
Free
Free
- 5 users
- 2.5K requests/month
- 1 workspace
Pro
$49/mo
- Unlimited workspaces and playgrounds
- 150MB max per dataset
- Overage $0.003 per request
Team
$500/mo
- 25 users
- 100K+ requests/month
- Overage $0.002 per request
Enterprise
Custom
- Custom limits
- RBAC and deployment approvals
- HIPAA with BAA
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
PromptLayer
- Friendly for non-engineers
- Simple prompt versioning
- Backtests on real traffic
- Less depth on agent tracing
- Limits on lower plans
- Smaller ecosystem
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 PromptLayer if you want:
- Friendly for non-engineers
- Simple prompt versioning
- Backtests on real traffic
Watch out: less depth on agent tracing.
Arthur vs PromptLayer FAQ
What is the difference between Arthur and PromptLayer?
Arthur: Discovery, monitoring and governance for enterprise AI agents. PromptLayer: Prompt management and evals for teams where non-engineers edit prompts. Both are models & apis tools.
Is Arthur or PromptLayer cheaper?
PromptLayer has the lower starting price: about $49 a month, against $60 for Arthur.
Do Arthur and PromptLayer have free plans?
Arthur: Yes. PromptLayer: Yes.
Who makes Arthur?
Arthur is made by Arthur AI, based in United States.
Who makes PromptLayer?
PromptLayer is made by PromptLayer, based in United States.
Which should I choose, Arthur or PromptLayer?
Choose Arthur if you value finds shadow agents across environments and free tier with unlimited seats. Choose PromptLayer if you value friendly for non-engineers and simple prompt versioning.