Datadog LLM vs Fiddler AI (2026)
Overview
Datadog's LLM Observability extends its industry-leading APM platform to AI applications. It provides end-to-end tracing from LLM calls to infrastructure metrics, prompt and completion tracking, cost analysis, and quality evaluation—all integrated with Datadog's existing monitoring, logging, and alerting stack. Ideal for enterprises already using Datadog who want unified observability across traditional and AI workloads.
Fiddler AI is an enterprise platform for observing, evaluating, and governing AI agents and ML models, with guardrails that run in your own environment.
Key features
Core capabilities each platform advertises.
- LLM monitoring within Datadog platform
- Unified APM + LLM observability
- Automatic instrumentation
- Cost and token tracking
- Integration with existing Datadog dashboards
- Agentic observability across multi-step agent workflows
- Continuous evaluations from testing through production
- Inline guardrails for PII, PHI, prompt injection, and jailbreaks
- AI governance, risk, and compliance reporting
Strengths and tradeoffs
What each tool does well, and the limitations to keep in mind.
Pros
- Seamless integration with Datadog's full observability suite for unified application monitoring
- Built-in sensitive data scanning and prompt injection detection for enhanced security
- Established enterprise platform with proven reliability and 9,700+ employees globally
- Automatic cost estimation for LLM requests using public pricing models
- Quick setup in seconds using their SDK
Cons
- Premium automatically activated at $120/day when LLM spans detected with no opt-out
- Can be expensive at scale compared to specialized LLM observability tools
- Requires familiarity with Datadog ecosystem for optimal usage
- Per-span pricing model may become costly for high-volume applications
Pros
- Covers AI agents and predictive ML models in one platform
- Evaluations and guardrails run in-environment, with no external LLM API call per check
- Free tier includes real-time guardrails
- Supports SaaS, VPC, on-premises, and AWS GovCloud deployment
Cons
- The free tier covers guardrails only; observability starts on the paid Developer plan
- VPC and on-premises deployment require the Enterprise plan
- Every plan on the pricing page starts with a demo request rather than self-serve signup
- No model routing or provider failover, so a gateway is a separate tool
Datadog LLM or Fiddler AI — which should you choose?
Choose Datadog LLM if you wantChoose if you want
- Unified monitoring for AI and traditional services
- Enterprise LLM monitoring at scale
- Correlating LLM performance with infrastructure
- Compliance and audit logging
- Large-scale production monitoring
Choose Fiddler AI if you wantChoose if you want
- Governing AI agents in regulated industries
- Monitoring predictive ML models for drift and performance
- Redacting PII and PHI on agent requests and responses
Compare Datadog LLM and Fiddler AI on your own traffic
Respan lets you trace LLM and agent calls across any model or framework, A/B test prompts on production traffic, and route requests across 1,000+ models through one gateway.
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