📖 The AI Tool Bible

Inspect AI vs LangSmith

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

 
Inspect AI
Evaluation
LangSmith
Evaluation
TaglineOpen-source LLM evaluation framework from the UK AI Security Institute with 200+ built-in benchmarks.LangChain's eval + observability platform.
CategoryEvaluationEvaluation
PricingFree· Free and open source (MIT-style license); you pay only for underlying model API usage.Freemium· Free starter; Plus $39/mo per seat
ModelMulti-modelPlatform (any LLM)
Editorial score—8.7 / 10
Use cases
llm-benchmarkingagent-evaluationsafety-testingcapture-the-flagcustom-evals
LLM tracingevalsLangChain integration
Pros
  • Backed by the UK AI Security Institute — serious pedigree for safety work
  • 200+ pre-built evaluations ready to run out of the box
  • Supports 20+ model providers plus sandboxed code execution
  • Composable Python API with CLI, Inspect View UI, and VS Code extension
  • Fully open source with no vendor lock-in
  • Tight LangChain integration
  • Strong tracing UX
  • Mature dataset/eval flows
  • Reasonable per-seat pricing
Cons
  • Python-first — no low-code path for non-engineers
  • Running large eval suites incurs real model API costs
  • Steeper learning curve than hosted eval platforms
  • Best value if you're on LangChain
  • UI can feel dense
Websiteinspect.aisi.org.ukwww.langchain.com
Pick Inspect AI if
  • ✅ Backed by the UK AI Security Institute — serious pedigree for safety work
  • ✅ 200+ pre-built evaluations ready to run out of the box
  • ✅ Supports 20+ model providers plus sandboxed code execution
  • ✅ Composable Python API with CLI, Inspect View UI, and VS Code extension
Pick LangSmith if
  • ✅ Tight LangChain integration
  • ✅ Strong tracing UX
  • ✅ Mature dataset/eval flows
  • ✅ Reasonable per-seat pricing
Compare a different pair →