Datadog LLM vs Respan (2026)
Updated February 28, 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.
Respan is LLM observability built into an AI router: nested traces for every agent run, evals on live production traffic, and a click from any score to its trace.
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
- Nested traces for every LLM call, tool run, and agent turn
- Threads for multi-turn sessions
- Online evals on live production traffic
- LLM-judge, code, and human evaluators
- Datasets from production logs and experiments at scale
- Monitors with Slack, email, and webhook alerts
- Prompt versioning and deployment without code changes
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
- Every score links to the trace that produced it
- Evals run on live production traffic, not only on test sets
- Built into the router, so there's no separate gateway to integrate
- Monitors alert the moment a metric breaches
- Unlimited seats on the free plan
Cons
- The free plan retains data for 7 days
- The free plan includes 1k scores and 2 evaluators
- Ingestion throughput is metered per tier, starting at 412 logs per minute on Free
Datadog LLM or Respan — 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 Respan if you wantChoose if you want
- Debugging agent failures down to the step that broke
- Catching quality regressions before users report them
- Turning production failures into test datasets
- Testing a prompt or model change against real cases before shipping
- Attributing LLM cost to each end customer
Compare Datadog LLM and Respan 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.
Try Respan free