kitio.aiArize AI vs Braintrust
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 $249 for Braintrust.
At a glance
Best for
Category
Pricing model
Starting price
Free plan
Made by
Based in
Rating
Key features
- Arize Phoenix open source
- Agent tracing
- Online evaluations
- Drift monitoring
- Debugging copilot
- Code and UI evals
- Experiment comparison
- CI eval gating
- Production logging
- Prompt playground
| Feature | Arize AI | Braintrust |
|---|---|---|
| Best for | AI observability and evaluation, plus the open-source Phoenix | Evaluation and observability platform for shipping reliable AI apps |
| Category | Models & APIs | Models & APIs |
| Pricing model | Freemium | Freemium |
| Starting price | $50/mo | $249/mo |
| Free plan | Yes | Yes |
| Made by | Arize AI | Braintrust |
| Based in | United States | United States |
| Rating | No ratings yet | No ratings yet |
| Key features |
|
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Pricing compared
Arize AI has the lower starting price: about $50 a month, against $249 for Braintrust.
Free plan
Cheapest paid plan
Top plan
Free trial
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
3 plans
Starter
Free
- $10 model credits/month
- 1 GB processed data
- 10k scores
- 14-day retention
Pro
$249/mo
- $100 model credits/month
- 5 GB processed data
- 50k scores
- 30-day retention, RBAC
Enterprise
Custom
- Custom retention and export
- On-prem or hosted deployment
- Premium support
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
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
Braintrust
- Strong eval workflow
- Good for product teams
- Hybrid data option
- Pro plan is expensive
- Not open source
- Overkill for hobby projects
Which one should you choose?
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.
Choose Braintrust if you want:
- Strong eval workflow
- Good for product teams
- Hybrid data option
Watch out: pro plan is expensive.
Arize AI vs Braintrust FAQ
What is the difference between Arize AI and Braintrust?
Arize AI: AI observability and evaluation, plus the open-source Phoenix. Braintrust: Evaluation and observability platform for shipping reliable AI apps. Both are models & apis tools.
Is Arize AI or Braintrust cheaper?
Arize AI has the lower starting price: about $50 a month, against $249 for Braintrust.
Do Arize AI and Braintrust have free plans?
Arize AI: Yes. Braintrust: Yes.
Who makes Arize AI?
Arize AI is made by Arize AI, based in United States.
Who makes Braintrust?
Braintrust is made by Braintrust, based in United States.
Which should I choose, Arize AI or Braintrust?
Choose Arize AI if you value free open-source phoenix and covers classic ml and llms. Choose Braintrust if you value strong eval workflow and good for product teams.