Fiddler AI vs Arize AI

Both compete in Observability & Monitoring. Fiddler AI positions itself as “Enterprise AI observability, security, and governance control plane for models and agents”, while Arize AIleads with “AI observability and evaluation platform for ML models, LLM apps, and agents”. The table below compares what each publishes.

Where Fiddler AI pulls ahead

Publishes support for EU AI Act, NIST AI RMF, which Arize AI does not. Regulated enterprises needing a single platform for ML, LLM, and agent observability with strong explainability and governance/audit capabilities.

Where Arize AI pulls ahead

Publishes support for SOC 2, which Fiddler AI does not. AI engineering and ML teams wanting unified LLM/agent observability and evaluation with an open-source (Phoenix) on-ramp to enterprise-scale monitoring

Both map to GDPR, HIPAA, so framework coverage alone will not separate them — the decision usually comes down to who operates the tool and how it fits your existing stack.

	Fiddler AI	Arize AI
Positioning	Enterprise AI observability, security, and governance control plane for models and agents	AI observability and evaluation platform for ML models, LLM apps, and agents
Category	Observability & Monitoring	Observability & Monitoring
Frameworks	EU AI Act, NIST AI RMF, GDPR, HIPAA	SOC 2, HIPAA, GDPR
Deployment	SaaS, Cloud, On-prem, API	SaaS, Cloud, On-prem, Open-source, API
Built for	GRC, Compliance, Risk, Data Science / ML, Security	Data Science / ML, Risk, Compliance
Founded	2018	2020
Headquarters	Palo Alto, California, USA	Berkeley, California, USA
Ownership	Private, independent; venture-backed	Private, independent, venture-backed (as of mid-2026)
Funding	Approximately $100M total as of 2026; $30M Series C led by RPS Ventures (Jan 2026), following a $32M Series B (2021). Investors include Insight Partners, Lightspeed, Lux Capital, and Capgemini Ventures.	~$135M total raised across 5 rounds, including a $70M Series C in February 2025 led by Adams Street Partners; earlier $38M Series B (2022) led by TCV
Pricing	Enterprise subscription; custom pricing via sales/demo (no public self-serve tiers)	Free open-source (Phoenix); commercial tiers with free/self-serve entry and enterprise plans (usage/seat-based, custom pricing)
Key capabilities	Model and agent performance monitoring Drift and data-integrity detection Real-time LLM guardrails Explainability (XAI) Bias and fairness tracking Audit trails and governance dashboards	End-to-end agent and LLM tracing Evaluation framework (span/trace/session evals, LLM-as-judge) Drift and performance monitoring Embedding and data quality analysis Bias/fairness monitoring Prompt testing and iteration
Integrations	Amazon SageMaker, Google Cloud Vertex AI, NVIDIA NIM, NVIDIA NeMo Guardrails, Databricks, Datadog	OpenAI, Anthropic, Google, Amazon Bedrock, LangChain, LangGraph, LlamaIndex, CrewAI, DSPy, OpenTelemetry / OpenInference
Notable customers	Brex, BigaBid	Reddit, DoorDash, Instacart, Uber, Spotify, PagerDuty, Booking.com
Best for	Regulated enterprises needing a single platform for ML, LLM, and agent observability with strong explainability and governance/audit capabilities.	AI engineering and ML teams wanting unified LLM/agent observability and evaluation with an open-source (Phoenix) on-ramp to enterprise-scale monitoring
Limitations	Enterprise-focused with custom pricing and no transparent public tiers; the breadth across ML, LLM, and agents can mean a steeper setup and learning curve for smaller teams.	Positioned as an observability and evaluation layer rather than a full GRC/policy-enforcement governance suite; enterprise features and depth may require the paid platform beyond open-source Phoenix, and the fast-evolving agent tooling can shift.

Which should you shortlist?

Choose Fiddler AI if regulated enterprises needing a single platform for ML, LLM, and agent observability with strong explainability and governance/audit capabilities.

Choose Arize AI if aI engineering and ML teams wanting unified LLM/agent observability and evaluation with an open-source (Phoenix) on-ramp to enterprise-scale monitoring

Neither is a substitute for a governance program. Whichever you pick, you still need people who can define the policies the tool enforces.

Full Fiddler AI profile →Full Arize AI profile →

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