DeepEval vs LangSmith
Detailed side-by-side comparison to help you choose the right tool
DeepEval
🔴DeveloperTesting & Quality
Open-source LLM evaluation framework with 50+ research-backed metrics including hallucination detection, tool use correctness, and conversational quality. Pytest-style testing for AI agents with CI/CD integration.
Was this helpful?
Starting Price
FreeLangSmith
🔴DeveloperAI Observability
LangSmith is LangChain's commercial observability, evaluation and prompt management platform for LLM apps and agents in production.
Was this helpful?
Starting Price
FreeFeature Comparison
Scroll horizontally to compare details.
💡 Our Take
Choose DeepEval if you use multiple agent frameworks (CrewAI, LlamaIndex, custom) and want framework-agnostic evaluation with research-backed metrics. Choose LangSmith if you're deeply invested in the LangChain ecosystem and want first-class tracing, debugging, and evaluation tightly integrated with LangChain/LangGraph. DeepEval wins on flexibility and metric breadth; LangSmith wins on LangChain-native developer experience.
DeepEval - Pros & Cons
Pros
- ✓Comprehensive LLM evaluation metric suite — 50+ metrics covering hallucination, relevancy, tool correctness, bias, toxicity, and conversational quality
- ✓Pytest integration feels natural for Python developers — LLM tests run alongside unit tests in existing CI/CD pipelines with deployment gating
- ✓Tool correctness metric specifically designed for validating AI agent behavior — checks correct tool selection, parameters, and sequencing
- ✓Open-source core (MIT license) runs locally at zero platform cost — only pay for LLM API calls used by metrics
- ✓Confident AI cloud offers low-cost tracing at $1/GB-month with adjustable retention — competitive pricing for the observability tier
- ✓Active development with frequent new metrics and features — grew from 14+ to 50+ metrics, backed by Y Combinator
Cons
- ✗Metrics require LLM API calls (GPT-4, Claude) for evaluation — adds cost that scales with dataset size and metric count
- ✗Some metrics can be computationally expensive and slow for large evaluation datasets, especially multi-turn conversational metrics
- ✗Confident AI cloud required for collaboration, dataset management, monitoring, and dashboards — open-source alone lacks team features
- ✗Metric accuracy depends on the evaluator model quality — weaker models produce less reliable scores, creating cost pressure to use expensive models
- ✗Free tier of Confident AI is restrictive: 5 test runs/week, 1 week data retention, 2 seats, 1 project
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.
Not sure which to pick?
🎯 Take our quiz →🔒 Security & Compliance Comparison
Scroll horizontally to compare details.
Price Drop Alerts
Get notified when AI tools lower their prices
Get weekly AI agent tool insights
Comparisons, new tool launches, and expert recommendations delivered to your inbox.