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Head-to-head · Llm Monitoring

Datadog LLM Observability vs Arize Phoenix

  • Updated Oct 2026
  • Both researched from official sources
  • 4 checks side by side
Higher score Datadog LLM Observability #2 in Llm Monitoring 9.1/10 Free plan Free plan✓ 3 of 3 features Visit Datadog
Arize Phoenix #7 in Llm Monitoring 8.5/10 Free plan Free plan✓ 2 of 3 features Visit Arize Phoenix

Datadog LLM Observability leads on 0 checks, Arize Phoenix on 0, and 4 are even. Who comes out ahead on the 4 yes/no, price and count checks where we have data for both products. The editor score weighs everything else too.

Our verdict

  • Highest scoreDatadog LLM Observability · 9.1/10
  • Free planboth
  • Most featuresDatadog LLM Observability · 3 of 3

Datadog LLM Observability scores higher on our rubric for llm monitoring: 9.1 against 8.5 out of 10; our editors rank them #2 and #7.

On deployment options, Arize Phoenix gives you Both where Datadog LLM Observability offers Cloud.

Datadog LLM Observability is the better fit for teams already using Datadog. Arize Phoenix is the better fit for teams wanting free, self-hosted LLM observability.

  • Datadog LLM Observability fits best

    Teams already using Datadog

  • Arize Phoenix fits best

    Teams wanting free, self-hosted LLM observability

Advertiser disclosure: iTechGuides is reader-supported. Vendors can pay for top positions in our rankings and for a place on other products' pages, and we may earn a commission when you click some links. Bought places stand at the number bought; this page and our disclosure say so. Paying vendors may get a fuller, more detailed review from our editors, and that review can change their score. How we rank.

Side by side

Feature Datadog LLM Observability 9.1/10 Visit ↗ Arize Phoenix 8.5/10 Visit ↗
At a glance
Editor score 9.1 8.5
Ranking #2 in Llm Monitoring #7 in Llm Monitoring
Best for Teams already using Datadog Teams wanting free, self-hosted LLM observability
Pricing model Free plan + paid Free
Starting price $160/mo Free
Free plan ✓ ✓
Free trial — —
Deployment Cloud Cloud, Self-hosted
Platforms Web Web
Support Docs Community, Docs
Integrations 10 integrations 11 integrations
Built for Small business, Mid-market, Enterprise Solo, Small business, Mid-market, Enterprise
Features Datadog LLM Observability 3/3 · Arize Phoenix 2/3
LLM tracing ✓ ✓
Evaluation support ✓ ✓
Alerts ✓ (best) Not checked yet
Specs
Deployment options Cloud Both
Trace retention 15 days Not checked yet
LLM providers OpenAI, Anthropic, Gemini, Vertex AI, AWS Bedrock Not checked yet
Our review
Pros
  • Links agent traces with backend services, infrastructure, and user sessions
  • Combines evaluations, datasets, experiments, and annotations
  • Free plan includes up to 40K LLM spans per month and full feature access
  • Traces model calls, retrieval, tool use, and custom logic
  • Combines LLM-based, code-based, and human evaluations
  • Includes prompt versioning, experiments, and token cost tracking
Cons
  • Cloud-only deployment
  • Free and Pro plans both retain traces for 15 days
  • Pro costs $160/month with annual billing; extra spans are metered
  • Support is centered on community resources and documentation
  • Its integration list is narrower than some alternatives
  • Teams seeking hosted use must choose Phoenix Cloud rather than local deployment
Our verdict

Datadog LLM Observability, now presented as Agent Observability, helps engineering teams monitor and troubleshoot LLM-powered applications and agents in development and production. It records model calls and workflows at span level,…

Read the review →

Arize Phoenix is an open-source observability and evaluation platform for AI applications and agents. It is aimed at teams that want to inspect how model calls, retrieval, tool use, and custom logic behave, then evaluate and refine those…

Read the review →
  1. Datadog LLM ObservabilityLlm Monitoring 9.1Free plan
  2. Arize PhoenixLlm Monitoring 8.5Free plan

Strengths and trade-offs

  • Datadog LLM Observability — where it wins

    • Links agent traces with backend services, infrastructure, and user sessions
    • Combines evaluations, datasets, experiments, and annotations
    • Free plan includes up to 40K LLM spans per month and full feature access

    Where it doesn't

    • Cloud-only deployment
    • Free and Pro plans both retain traces for 15 days
    • Pro costs $160/month with annual billing; extra spans are metered

  • Arize Phoenix — where it wins

    • Traces model calls, retrieval, tool use, and custom logic
    • Combines LLM-based, code-based, and human evaluations
    • Includes prompt versioning, experiments, and token cost tracking

    Where it doesn't

    • Support is centered on community resources and documentation
    • Its integration list is narrower than some alternatives
    • Teams seeking hosted use must choose Phoenix Cloud rather than local deployment
  • Datadog LLM Observability9.1/10 · Free plan

    LLM tracing and evaluation with Datadog context, plus a free plan and cloud-only deployment.

    Visit DatadogFull verdict →
  • Arize Phoenix8.5/10 · Free plan

    A free, self-hostable stack for tracing, evaluating, and iterating on LLM applications.

    Visit Arize PhoenixFull verdict →

More comparisons

All llm monitoring comparisons → · Full ranking →

Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026

Last updated · How we research and update