# LangSmith Evaluation

**Canonical:** https://apis.io/apis/evals/langsmith-evaluation/  
**Provider:** Evals — https://apis.io/providers/evals/  
**Base URL:** https://api.smith.langchain.com  
**Documentation:** https://docs.langchain.com/langsmith/evaluation-concepts

LangSmith Evaluation is one of 20 APIs that [Evals](https://apis.io/providers/evals/) publishes on the [APIs.io](https://apis.io/) network. Tagged areas include LangChain, LLM as a Judge, Pairwise, Reference-Free, and Online and Offline. The published artifact set on APIs.io includes API documentation and pricing.

LangSmith Evaluation is LangChain's evaluation framework for measuring application quality across the lifecycle. The docs describe evals as "a way to breakdown what 'good' looks like and measure it." It supports code evaluators (deterministic rules), LLM-as-judge evaluators (reference-based or reference-free), and heuristic checks (length, latency, keywords). Concepts include datasets and examples, experiments, and pairwise evaluation for relative comparisons.

## Machine-readable artifacts (3)

- **Documentation** — https://docs.langchain.com/langsmith/evaluation-concepts
- **Portal** — https://smith.langchain.com
- **Pricing** — https://www.langchain.com/pricing-langsmith

## Other Evals APIs (12)

- [OpenAI Evals](https://apis.io/apis/evals/openai-evals/)
- [Inspect AI](https://apis.io/apis/evals/inspect-ai/)
- [Braintrust](https://apis.io/apis/evals/braintrust/)
- [Promptfoo](https://apis.io/apis/evals/promptfoo/)
- [Helicone](https://apis.io/apis/evals/helicone/)
- [Patronus AI](https://apis.io/apis/evals/patronus-ai/)
- [DeepEval (Confident AI)](https://apis.io/apis/evals/deepeval-confident-ai/)
- [Arize AI (Phoenix)](https://apis.io/apis/evals/arize-ai-phoenix/)
- [Galileo](https://apis.io/apis/evals/galileo/)
- [Humanloop](https://apis.io/apis/evals/humanloop/)
- [TruLens](https://apis.io/apis/evals/trulens/)
- [Weights and Biases Weave](https://apis.io/apis/evals/weights-and-biases-weave/)

## Tags

LangChain, LLM as a Judge, Pairwise, Reference-Free, Online and Offline

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Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/apis/evals/langsmith-evaluation/). The API's provider profile, Kin Score and agent-readiness rating are at https://apis.io/providers/evals/.