kitio.aiWeights & Biases vs Arize AI
A side-by-side look at pricing plans, free tiers, features, pros and cons, updated for 2026. Arize AI has the lower starting price: about $50 a month, against $60 for Weights & Biases.
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
- Arize Phoenix open source
- Agent tracing
- Online evaluations
- Drift monitoring
- Debugging copilot
| Feature | Weights & Biases | Arize AI |
|---|---|---|
| Best for | Experiment tracking and LLM observability, now part of CoreWeave | AI observability and evaluation, plus the open-source Phoenix |
| Category | Models & APIs | Models & APIs |
| Pricing model | Freemium | Freemium |
| Starting price | $60/mo | $50/mo |
| Free plan | Yes | Yes |
| Made by | CoreWeave | Arize AI |
| Based in | United States | United States |
| Rating | No ratings yet | No ratings yet |
| Key features |
|
|
Pricing compared
Arize AI has the lower starting price: about $50 a month, against $60 for Weights & Biases.
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
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
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
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 Weights & Biases if you want:
- Industry-standard experiment tracking
- Polished dashboards
- Covers training and LLM apps
Watch out: pricing jumps for larger teams.
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.
Weights & Biases vs Arize AI FAQ
What is the difference between Weights & Biases and Arize AI?
Weights & Biases: Experiment tracking and LLM observability, now part of CoreWeave. Arize AI: AI observability and evaluation, plus the open-source Phoenix. Both are models & apis tools.
Is Weights & Biases or Arize AI cheaper?
Arize AI has the lower starting price: about $50 a month, against $60 for Weights & Biases.
Do Weights & Biases and Arize AI have free plans?
Weights & Biases: Yes. Arize AI: Yes.
Who makes Weights & Biases?
Weights & Biases is made by CoreWeave, based in United States.
Who makes Arize AI?
Arize AI is made by Arize AI, based in United States.
Which should I choose, Weights & Biases or Arize AI?
Choose Weights & Biases if you value industry-standard experiment tracking and polished dashboards. Choose Arize AI if you value free open-source phoenix and covers classic ml and llms.