Arize Phoenix vs LangSmith

Detailed side-by-side comparison to help you choose the right tool

Arize Phoenix

🔴Developer

Business Analytics

Open-source LLM observability platform that helps debug AI applications through detailed tracing, evaluation, and prompt experimentation with notebook-first design.

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Starting Price

Free

LangSmith

🔴Developer

AI Observability

LangSmith is LangChain's commercial observability, evaluation and prompt management platform for LLM apps and agents in production.

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Starting Price

Free

Feature Comparison

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FeatureArize PhoenixLangSmith
CategoryBusiness AnalyticsAI Observability
Pricing Plans18 tiers59 tiers
Starting PriceFreeFree
Key Features
  • UMAP Embedding Visualization
  • OpenInference Tracing
  • Research-Grade Evaluations
  • Tracing for any LLM stack via Python/TypeScript SDKs or OpenTelemetry
  • LLM-as-judge, code-based and pairwise evaluations
  • Versioned prompts with production A/B traffic splits

Arize Phoenix - Pros & Cons

Pros

  • Open-source with complete self-hosting capabilities ensuring sensitive data never leaves your environment
  • UMAP embedding visualization provides unique insights into retrieval quality and distribution drift
  • Research-grade evaluation framework with built-in evaluators based on published methodologies
  • Notebook-first design launches with one line of code, making it immediately accessible for data scientists
  • OpenInference tracing standard provides vendor-neutral observability compatible with OpenTelemetry ecosystems
  • Specialized RAG metrics and retrieval analysis capabilities unmatched by general-purpose observability tools
  • Free open-source version includes all core analytical features without restrictions or feature gates

Cons

  • Limited prompt management, A/B testing, and team collaboration features compared to full-platform alternatives
  • UI design prioritizes analytical functionality over polished user experience and operational workflows
  • Local-first architecture requires additional infrastructure work to scale to team-wide production monitoring
  • Embedding analysis features are most valuable for RAG applications and less differentiated for non-retrieval use cases

LangSmith - Pros & Cons

Pros

  • Best-in-class integration if you already use LangChain or LangGraph.
  • Eval suites are practical enough to actually gate releases on, not just dashboards.
  • Self-hosted Enterprise tier covers SOC 2 and regulated environments.

Cons

  • Per-trace pricing on Plus surprises teams that scale production traffic quickly.
  • Non-LangChain stacks work but trade ergonomic polish for SDK overhead.
  • Some eval features require additional LLM spend on top of the platform fee.

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🔒 Security & Compliance Comparison

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Security FeatureArize PhoenixLangSmith
SOC2✅ Yes
GDPR✅ Yes
HIPAA
SSO✅ Yes
Self-Hosted🔀 Hybrid
On-Prem✅ Yes
RBAC✅ Yes
Audit Log✅ Yes
Open Source❌ No
API Key Auth✅ Yes
Encryption at Rest✅ Yes
Encryption in Transit✅ Yes
Data ResidencyUS, EU
Data Retentionconfigurable
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