Fiddler AI vs Arthur

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

Where Fiddler AI pulls ahead

Publishes support for GDPR, which Arthur does not. Regulated enterprises needing a single platform for ML, LLM, and agent observability with strong explainability and governance/audit capabilities.

Where Arthur pulls ahead

Publishes support for SOC 2, which Fiddler AI does not. Enterprises operationalizing generative and agentic AI that want flexible deployment (SaaS, VPC, on-prem) and an open-source evaluation engine alongside governance controls.

Both map to EU AI Act, NIST AI RMF, 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	Arthur
Positioning	Enterprise AI observability, security, and governance control plane for models and agents	AI performance, evaluation, and governance platform for ML, generative, and agentic systems
Category	Observability & Monitoring	Observability & Monitoring
Frameworks	EU AI Act, NIST AI RMF, GDPR, HIPAA	NIST AI RMF, EU AI Act, SOC 2, HIPAA
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, Compliance, Risk, Security
Founded	2018	2018
Headquarters	Palo Alto, California, USA	New York, New York, USA
Ownership	Private, independent; venture-backed	Private, independent; venture-backed
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.	Approximately $63M total across three rounds; $42M Series B (2022) led by Acrew Capital and Greycroft, with Index Ventures and Work-Bench. No publicly reported round since.
Pricing	Enterprise subscription; custom pricing via sales/demo (no public self-serve tiers)	Self-serve SaaS tier plus enterprise subscription for VPC/on-prem; open-source Arthur Engine available free
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	Pre-production, runtime, and production evaluations Real-time guardrails (prompt injection, PII, toxicity) Hallucination and groundedness detection Agent trace visualization and tool-selection metrics Drift and performance monitoring for classical ML Open-source Arthur Engine
Integrations	Amazon SageMaker, Google Cloud Vertex AI, NVIDIA NIM, NVIDIA NeMo Guardrails, Databricks, Datadog	OpenAI, Anthropic Claude, Meta Llama, Google Gemini, Together.ai, CrewAI, AutoGen, smolagents, Slack, Jira
Notable customers	Brex, BigaBid	None published
Best for	Regulated enterprises needing a single platform for ML, LLM, and agent observability with strong explainability and governance/audit capabilities.	Enterprises operationalizing generative and agentic AI that want flexible deployment (SaaS, VPC, on-prem) and an open-source evaluation engine alongside governance controls.
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.	Named enterprise references are limited publicly; funding has not advanced past its 2022 Series B, and the rapid pivot toward agentic AI means several governance features are relatively new.

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 Arthur if enterprises operationalizing generative and agentic AI that want flexible deployment (SaaS, VPC, on-prem) and an open-source evaluation engine alongside governance controls.

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 Arthur profile →

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