Fiddler AI
Fiddler AI: A governance-focused observability platform for LLMs, agents, retrieval, and predictive models. Ranked #10 of 26 in LLM Observability Tools by our editors (8.5/10); pricing: Free plan; best for organizations prioritizing guardrails and governance.
At a glance
- Editor score8.5 / 10
- PricingFree plan
- Best forOrganizations prioritizing guardrails and governance
- Free planYes
- Paid from$0.002/unit usage-based
- LLM tracingYes
- Founded2018 · Palo Alto, California, United States
- Facts checked20 Sep 2026
Where it wins
- Hierarchical tracing covers applications, sessions, agents, traces, and spans
- Real-time guardrails address hallucinations, PII/PHI, and prompt injection
- Evaluations, cost visibility, alerts, and governance evidence in one platform
Where it doesn't
- Platform access is limited to web and API
- Developer pricing is based on trace usage rather than a fixed fee
- Broader capabilities may exceed the needs of teams seeking basic tracing
Our verdict on Fiddler AI
Fiddler AI is an observability and security platform for teams developing and operating LLM applications, AI agents, and predictive models. It covers development-to-production workflows with testing, evaluations, monitoring, hierarchical traces, diagnostics, guardrails, governance, and compliance-oriented reporting. Teams that need visibility across agent behavior, retrieval, tool calls, costs, and safety controls are the clearest fit.
Pricing is freemium, with a Free plan and a Developer plan priced at $0.002 per trace. The published plans show an Enterprise tier alongside Free and Developer, while the Developer pricing is usage-based rather than presented as a monthly or annual fee. Paid capabilities are centered on operational scale and governance needs, including role-based access control, single sign-on, alerts, dashboards, root-cause analysis, and governance evidence. SaaS, VPC, and on-premises deployment options support different operating environments, while access is provided through web and API platforms.
Fiddler AI’s standout strength is the breadth of its diagnostic and safety coverage. Hierarchical tracing connects the application and session level to agents, traces, and spans; evaluations can use datasets, experiments, comparisons, automated judges, or custom judges. Teams can inspect retrieval, generation, tool calls, and agent handoffs, while real-time guardrails address hallucinations, toxicity, PII/PHI, prompt injection, and jailbreaks. Integrations include LangGraph, Amazon Bedrock, AWS Strands Agents, Azure OpenAI, OpenAI, Llama, Google Vertex AI, and OpenTelemetry. Choose Fiddler AI when governance and guardrails matter as much as tracing; teams seeking only basic observability may find its wider scope unnecessary.
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Fiddler AI pricing
All 3 Fiddler AI plans and prices →
Fiddler AI fact sheet
| Free plan | Yes |
|---|---|
| Paid from | $0.002/unit usage-based |
| LLM tracing | Yes |
| LLM evaluations | Yes |
| Prompt management | Yes |
| Agent tracing | Yes |
| Retrieval tracing | Yes |
| Token cost tracking | Yes |
| Deployment options | Both |
| Deployment | Cloud, Self-hosted |
| Platforms | Web |
| Compliance & security | SOC 2, HIPAA, SSO/SAML |
| Support | Docs |
| Built for | Mid-market, Enterprise (editorial estimate) |
| Integrations | 8 integrations: LangGraph, Amazon Bedrock, AWS Strands Agents, Azure OpenAI, OpenAI, Llama … |
| Pricing | Free plan (source) |
| Website | fiddler.ai |
| Facts checked | 20 Sep 2026 |
Fiddler AI integrations
Fiddler AI lists 8 integrations on its own site.
- LangGraph
- Amazon Bedrock
- AWS Strands Agents
- Azure OpenAI
- OpenAI
- Llama
- Google Vertex AI
- OpenTelemetry
Alternatives to Fiddler AI
- Arize AXBroad LLM observability with tracing, evaluations, prompts, agents, RAG, and cost tracking.9.4
- LangfuseA broad observability platform with open-source deployment and accessible paid tiers.9.3
- Arize PhoenixA free platform for tracing, evaluating, and improving LLM applications.9.2
See all Fiddler AI alternatives →
Also Ranked In
Fiddler AI is ranked in 6 of our directories.
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Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
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