kitio.aiWeights & Biases vs Fiddler AI
A side-by-side look at pricing plans, free tiers, features, pros and cons, updated for 2026. Weights & Biases starts at $60/mo and Fiddler 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
- Experiment tracking
- Hyperparameter sweeps
- Model registry
- Weave LLM tracing
- Reports
- Agent tracing and observability
- Continuous evaluations
- Real-time guardrails
- ML model monitoring
- AI governance and compliance
- Custom evaluators
| Feature | Weights & Biases | Fiddler AI |
|---|---|---|
| Best for | Experiment tracking and LLM observability, now part of CoreWeave | Evaluation, observability and guardrails for AI agents and ML models |
| Category | Models & APIs | Models & APIs |
| Pricing model | Freemium | Freemium |
| Starting price | $60/mo | See pricing page |
| Free plan | Yes | Yes |
| Made by | CoreWeave | Fiddler Labs |
| Based in | United States | United States |
| Rating | No ratings yet | No ratings yet |
| Key features |
|
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Pricing compared
Weights & Biases starts at $60/mo and Fiddler AI starts at See pricing page. Check both pricing pages for current plans.
Free plan
Cheapest paid plan
Top plan
Free trial
3 plans
Free
Free
- Experiment tracking for individuals
- Limited storage
Pro
$60/mo
- Starting price
- Team collaboration features
- Higher usage limits
Enterprise
Contact sales
- SSO and advanced security
- Dedicated support
2 plans
Developer
$0.002 / trace
- Custom evaluators
- Bring your own judge
- RBAC and SSO
- SaaS deployment
Enterprise
Contact sales
- Enterprise guardrails
- SaaS, VPC or on-prem
- Named success manager
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
Weights & Biases
- Industry-standard experiment tracking
- Polished dashboards
- Covers training and LLM apps
- Pricing jumps for larger teams
- Weave ingestion billed by size
- Sign-in moved to CoreWeave
Fiddler AI
- Covers both LLM agents and classic ML
- Pay-per-trace developer pricing
- Self-hosted and VPC options
- Enterprise features need a sales contract
- Free tier limits are not spelled out
- Broad platform with a learning curve
Which one should you choose?
Choose Weights & Biases if you want:
- Industry-standard experiment tracking
- Polished dashboards
- Covers training and LLM apps
Watch out: pricing jumps for larger teams.
Choose Fiddler AI if you want:
- Covers both LLM agents and classic ML
- Pay-per-trace developer pricing
- Self-hosted and VPC options
Watch out: enterprise features need a sales contract.
Weights & Biases vs Fiddler AI FAQ
What is the difference between Weights & Biases and Fiddler AI?
Weights & Biases: Experiment tracking and LLM observability, now part of CoreWeave. Fiddler AI: Evaluation, observability and guardrails for AI agents and ML models. Both are models & apis tools.
Is Weights & Biases or Fiddler AI cheaper?
Weights & Biases starts at $60/mo and Fiddler AI starts at See pricing page. Check both pricing pages for current plans.
Do Weights & Biases and Fiddler AI have free plans?
Weights & Biases: Yes. Fiddler AI: Yes.
Who makes Weights & Biases?
Weights & Biases is made by CoreWeave, based in United States.
Who makes Fiddler AI?
Fiddler AI is made by Fiddler Labs, based in United States.
Which should I choose, Weights & Biases or Fiddler AI?
Choose Weights & Biases if you value industry-standard experiment tracking and polished dashboards. Choose Fiddler AI if you value covers both llm agents and classic ml and pay-per-trace developer pricing.