Fiddler AI alternatives

3 tools to consider instead of Fiddler AI, shown against it.

Fiddler AI Evidently AI Arize AI WhyLabs
Vendor Fiddler AI, Inc. Evidently AI, Inc. Arize AI, Inc. WhyLabs, Inc. (discontinued operations in 2025; codebase open-sourced)
Pricing model Usage-based Free tier + paid plans Free tier + paid plans Open source + paid options
Free tier Yes Yes Yes Yes
Deployment Cloud, Self-hosted Cloud, Self-hosted Cloud, Self-hosted Self-hosted
Open source No Yes (Apache-2.0) No Yes (Apache-2.0)
Best for Teams needing both monitoring and real-time safety guardrails for LLM/agent applications in production. Teams needing open-source-first drift and data-quality monitoring for deployed ML or LLM systems. AI-native teams needing unified monitoring across both predictive ML models and LLM applications. Developers who want the open-sourced whylogs/LangKit libraries rather than a supported commercial platform.
Pricing

A free tier covers basic real-time guardrails; the Developer tier is billed per trace; Enterprise adds flexible deployment and support and is custom-quoted.

Free $0
Developer $0.002 per trace
Enterprise Custom

Prices read from the vendor's own page on September 21, 2026. Vendors change prices; check the source before you budget.

The open-source library and self-hosted platform are free; Evidently Cloud has paid tiers, but no self-serve figures were shown on the vendor's pricing page in this session, and higher tiers are sold via sales conversation.

Checked on the vendor's own page on September 21, 2026: no prices are published. Expect to be quoted.

Free tier covers a limited number of trace spans and issues per month; Pro is a flat monthly rate with higher caps; Enterprise is custom-quoted with unlimited volume and choice of SaaS or self-hosted deployment.

AX Free $0
AX Pro $50/month
AX Enterprise Custom

Prices read from the vendor's own page on September 21, 2026. Vendors change prices; check the source before you budget.

The commercial WhyLabs platform has been discontinued; only the open-source whylogs and LangKit libraries remain, and they are free.

Pricing has not been verified yet — see the vendor's site.

Features
  • Production drift and performance monitoring
  • Real-time LLM guardrails (hallucination, toxicity, PII/PHI, prompt injection)
  • Model explainability tooling
  • Agentic and predictive-system observability
  • Custom evaluators / bring-your-own-judge
  • Role-based access control and SSO
  • VPC and on-premises deployment options
  • Data and target drift detection
  • Data-quality checks and test suites
  • Model performance monitoring over time
  • LLM output evaluation (hallucination, toxicity, relevance)
  • Pre-built HTML/JSON reports and dashboards
  • CI/CD integration for automated checks
  • Open-source core with a hosted Cloud dashboard
  • Production drift and data-quality monitoring
  • LLM/agent tracing and evaluation
  • Human annotation workflows
  • Root-cause and issue detection
  • Experiment comparison for model/prompt versions
  • Self-hosted and SaaS deployment options
  • Alerting and dashboarding
  • Statistical data profiling without storing raw data (whylogs)
  • Data and concept drift detection
  • LLM input/output monitoring (LangKit)
  • Anomaly detection on production data
  • Lightweight, open-source logging library
  • No hosted commercial dashboard (discontinued)

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