Fiddler AI

What is Fiddler AI?

Fiddler AI is an observability and security platform for teams running AI agents and predictive machine learning models. It traces activity from application down to session, agent, trace and span, scores it with more than 100 built-in and custom metrics, and raises alerts when quality drops. Its guardrails sit in the request and response path of an agent and respond in under 80 milliseconds, screening for hallucinations, toxicity, PII and PHI, prompt injection and jailbreak attempts. Evaluations run on Fiddler's own Centor models inside your environment, so no external LLM calls are needed, and you can still plug in outside judges. Every enforcement decision is logged for audit purposes. Deployment options include SaaS, VPC and on-premises. Fiddler lists a Free plan with guardrails, a Developer plan at $0.002 per trace, and an Enterprise plan with custom terms.

Use cases

• Monitor AI agents in production
• Block prompt injection and jailbreaks
• Redact PII and PHI in agent traffic
• Evaluate agents before launch
• Detect drift in ML models
• Produce audit records for AI governance
• Track token cost by user and team

Who it's for

• AI engineers
• Data scientists
• Platform and DevOps teams
• Security and compliance teams

Why use Fiddler AI

• Puts monitoring, evaluation, enforcement and governance in one system instead of several separate tools.
• Runs guardrails and evaluations on in-environment models, which the vendor says avoids per-evaluation calls to external LLM providers.
• Starts free with real-time guardrails, then moves to usage-based pricing at $0.002 per trace.
• Works across frameworks and clouds, so it is not tied to a single model vendor or hyperscaler.
• Keeps an auditable trail of each decision for compliance reviews.

Fiddler AI features

• Tracing from application through session, agent, trace and span
• 100+ pre-defined metrics plus custom metrics
• Real-time guardrails with latency under 80ms
• Centor models that run in your own environment
• Custom evaluators and bring-your-own judge
• Test datasets and experiments to compare prompts, models and guardrails
• Real-time alerts when performance drops
• Role-based access control and SSO
• Audit log of every enforcement decision
• OpenTelemetry-based ingestion of structured and unstructured data

Fiddler AI integrations

• LangGraph
• Amazon Bedrock
• AWS Strands Agents
• Azure OpenAI
• Amazon SageMaker Studio
• OpenAI
• Anthropic
• OpenTelemetry

How to get started with Fiddler AI

1. Send traces and model data to Fiddler from your agent framework or ML pipeline, in real time or in batches.
2. Test agents before launch using curated datasets, stress tests and experiments that compare prompts, models and guardrail settings.
3. Turn on guardrails so each request and response is screened inline for risks such as PII, toxicity and jailbreaks.
4. Watch dashboards and alerts to trace failures back to the span or model input that caused them.
5. Review the governance records to show who triggered each enforcement action and what happened.

Fiddler AI limitations

• The Developer plan is billed per trace, so cost grows with volume
• Enterprise guardrails, VPC and on-premises deployment need the Enterprise plan
• Enterprise pricing is not published

Fiddler AI pricing

Yes, Fiddler AI has a free plan. Paid plans start at $0 usage-based, according to the official pricing page on 24 Oct 2026.

Fiddler AI plans

• Free

  Free

  • Real-time guardrails
  • Hallucination, toxicity, PII/PHI checks
  • Prompt injection and jailbreak detection
  • Latency under 80ms

• Developer

  $0.002 per trace

  • Everything in Free
  • Unified AI observability
  • Tests and experiments
  • Custom evaluators and bring your own judge
  • Role-based access control and SSO
  • SaaS deployment

• Enterprise

  Custom

  • Everything in Developer
  • Enterprise-grade guardrails
  • SaaS, VPC or on-premise
  • Dedicated support channels
  • Named Customer Success Manager

Plans as listed on the official pricing page on 24 Oct 2026. Prices can change and may vary by country or exclude tax. Check the official pricing page.

Fiddler AI alternatives

The main Fiddler AI alternatives listed on Debuly are Galileo, Langfuse, Weights & Biases, Arize AX, Fireraven and Holistic AI. The table compares pricing and platforms; order is A–Z.

1. 

   Arize AX

   Observability and evaluation platform for AI agents and LLM apps, with tracing, issue detection and experiments on a free plan.

   Developer platformsAutomation and agentsCoding
   FreemiumVisit Arize AX (official site)
2. 

   Fireraven

   Runtime guardrails and automated red-teaming that secure AI agents and help prove compliance.

   Developer platformsAutomation and agents
   Visit Fireraven (official site)
3. 

   Galileo

   AI observability and eval platform that tunes evals to your data and turns them into guardrails for LLM apps and agents.

   Developer platformsAutomation and agents
   FreemiumVisit Galileo (official site)
4. 

   Holistic AI

   Enterprise AI governance platform that inventories every model and agent, tests them for risk and bias, and enforces policy with audit evidence.

   Developer platformsAutomation and agentsProductivity
   Contact salesVisit Holistic AI (official site)
5. 

   Langfuse

   Open-source LLM observability and evaluation platform for tracing agents, managing prompts and scoring outputs.

   Developer platformsAutomation and agentsCoding
   FreemiumVisit Langfuse (official site)
6. 

   Weights & Biases

   Platform for tracking ML experiments and tracing, evaluating and monitoring LLM apps and agents with W&B Weave.

   Developer platformsCodingAutomation and agents
   FreemiumVisit Weights & Biases (official site)

Fiddler AI FAQ

Sources & verification

Facts on this page come from the official sources below, each with the date we read it. Written by Debuly; the vendor did not review this page.

Image credits

• Logo: from cdn.prod.website-files.com · fetched 23 Oct 2026 · Vendor trademark, used only to identify the product; removed on request
• Cover: none collected yet, so a generated tile is shown.

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