Arthur vs Fiddler AI

Arthur helps enterprises find AI agents across their environments and provides tools to observe and govern them. Discovery sensors monitor OpenTelemetry streams, MCP servers, network traffic, cloud APIs, and employee endpoints. The platform traces agent steps, tool calls, retrieved context, costs, latency, and behavior over time. Its governance features apply machine-checkable policies and provide real-time guardrail verdicts for prompt injection, PII exposure, restricted models, and off-policy tool use. Deployment options include hosted SaaS, on-premises, and hybrid; for hybrid setups, the evals engine runs beside customer workloads so sensitive data stays in the environment. Arthur lists RBAC, SSO, and deployed engineering support with every deployment option. Documented integrations include OpenAI, Anthropic, LangChain, LiteLLM, CrewAI, LlamaIndex, OpenAI Agents, Google ADK, AWS Bedrock, and Mastra. The Free plan is free, with up to four use cases, two projects, and seven-day data retention. Premium is $60 a month; Enterprise pricing is custom.

Fiddler AI provides observability and security for AI agents and predictive applications. It evaluates agents and models during development, then monitors them in production, with diagnostics spanning more than 100 built-in and custom metrics such as hallucination, toxicity, PII/PHI, drift, performance, and business KPIs. Real-time guardrails can detect risks and pause, reroute, or escalate agent actions. The platform records decisions, actions, evaluations, and policy outcomes to support audit evidence for requirements including GDPR, HIPAA, NAIC, and SR 11-7. It names LangGraph, Amazon Bedrock, and AWS Strands Agents as native framework support, and is built on OpenTelemetry standards. Deployment options include cloud SaaS, VPC, on-premises, and air-gapped environments. Fiddler says it is SOC 2 Type II certified, complies with HIPAA, and encrypts data in transit and at rest. Plans include Free at free, Developer at a price agreed with the maker billed per trace, and Enterprise with no listed price. The company was founded in 2018 and is headquartered in Palo Alto, California.