Arize AI vs Fiddler AI vs WhyLabs
LLM and ML observability platforms. Data comes from each vendor’s profile; see each profile for its sources and last-checked date.
Arize AI
Berkeley, United States
Ship Agents that Work — AI & Agent Engineering Platform for development, observability, and evaluation.
Phoenix (self-hosted open source, free); AX Free (SaaS, free, 25K spans/month, 1 GB/month, 15-day retention); AX Pro ($50/month, 50K spans/month, 100 GB/month, 30-day retention); AX Enterprise (custom pricing, SaaS or self-hosted). Additional spans at $10/million on Pro; additional GB at $3/GB.
Fiddler AI
Palo Alto, United States
Observability, evaluation and guardrails for predictive models and LLM agents, with guardrails that run inside your own cloud
Three plans: Free (real-time guardrails for hallucinations, toxicity, PII/PHI, prompt injection and jailbreaks, powered by Fiddler's Centor models); Developer at $0.002 per trace (adds unified observability with tests and experiments for agentic and predictive systems, custom evaluators and bring-your-own judge, role-based access control and SSO; SaaS only); and Enterprise, priced by sales (adds enterprise-grade guardrails and scale, SaaS, VPC or on-premises deployment, and a named customer success manager). The pricing page lists no trace or user limits.
WhyLabs
Seattle, United States
The AI Observability Platform
Free tier for 1 model; $100/month for 2 models, scaling per model up to enterprise at $8,333/month (AWS Marketplace listing).
Framework coverage
Which frameworks each vendor publicly claims to support. Sourced from their own product pages.
| Framework | Arize AI | Fiddler AI | WhyLabs |
|---|---|---|---|
| EU Artificial Intelligence Act | limited | ||
| Health Insurance Portability and Accountability Act | Partial | ||
| ISO/IEC 42001:2023 AI Management System | Adjacent | ||
| NIST AI Risk Management Framework | Adjacent | ||
| SOC 2 (Service Organization Control 2) | Certified | Certified |
Core facts
| Founded | 2020 | 2018 | 2019 |
| HQ | Berkeley, United States | Palo Alto, United States | Seattle, United States |
| Employees | 51-200 | — | 11-50 |
| Pricing | Phoenix (self-hosted open source, free); AX Free (SaaS, free, 25K spans/month, 1 GB/month, 15-day retention); AX Pro ($50/month, 50K spans/month, 100 GB/month, 30-day retention); AX Enterprise (custom pricing, SaaS or self-hosted). Additional spans at $10/million on Pro; additional GB at $3/GB. | Three plans: Free (real-time guardrails for hallucinations, toxicity, PII/PHI, prompt injection and jailbreaks, powered by Fiddler's Centor models); Developer at $0.002 per trace (adds unified observability with tests and experiments for agentic and predictive systems, custom evaluators and bring-your-own judge, role-based access control and SSO; SaaS only); and Enterprise, priced by sales (adds enterprise-grade guardrails and scale, SaaS, VPC or on-premises deployment, and a named customer success manager). The pricing page lists no trace or user limits. | Free tier for 1 model; $100/month for 2 models, scaling per model up to enterprise at $8,333/month (AWS Marketplace listing). |
| Open source | no | no | no |
| Status | acquired | active | acquired-discontinued |