📖 The AI Tool Bible

LangSmith vs Respan (formerly Keywords AI)

A side-by-side look at pricing, capabilities, pros, cons, and our editorial scores.

 
LangSmith
Evaluation
Respan (formerly Keywords AI)
Evaluation
TaglineLangChain's eval + observability platform.LLM engineering platform combining a multi-model gateway with tracing, evals, and prompt management.
CategoryEvaluationEvaluation
PricingFreemium· Free starter; Plus $39/mo per seatFreemium· Free tier; paid plans (pricing not public); enterprise on request
ModelPlatform (any LLM)Multi-model (500+ via gateway)
Editorial score8.7 / 10—
Use cases
LLM tracingevalsLangChain integration
llm-observabilityprompt-managementmodel-routingevalsproduction-monitoring
Pros
  • Tight LangChain integration
  • Strong tracing UX
  • Mature dataset/eval flows
  • Reasonable per-seat pricing
  • Unified gateway to 500+ models with fallback and error handling
  • End-to-end loop: trace, evaluate, monitor, version prompts in one UI
  • Eval system mixes rules, AI judges, and human review
  • Broad SDK and framework coverage (LangChain, LlamaIndex, Vercel AI SDK)
  • YC-backed with serious production scale (80T+ tokens claimed)
Cons
  • Best value if you're on LangChain
  • UI can feel dense
  • Closed source — no self-host option for most customers
  • Paid pricing not transparent on the site
  • Recent rebrand from Keywords AI may cause doc and link churn
  • Gateway dependency adds a network hop and vendor lock-in
Websitewww.langchain.comwww.respan.ai
Pick LangSmith if
  • ✅ Tight LangChain integration
  • ✅ Strong tracing UX
  • ✅ Mature dataset/eval flows
  • ✅ Reasonable per-seat pricing
Pick Respan (formerly Keywords AI) if
  • ✅ Unified gateway to 500+ models with fallback and error handling
  • ✅ End-to-end loop: trace, evaluate, monitor, version prompts in one UI
  • ✅ Eval system mixes rules, AI judges, and human review
  • ✅ Broad SDK and framework coverage (LangChain, LlamaIndex, Vercel AI SDK)
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