LangSmith alternatives in 2026: 24 tools like LangSmith

Closest: LLM Evaluation & Benchmarking

Braintrust

LLM evaluation and prompt management platform

CuratedWeb

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DeepEval

Open-source LLM evaluation framework

Curated

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EleutherAI LM Evaluation Harness

Framework for few-shot language model evaluation

Curated

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HELM

Holistic evaluation of language models

Curated

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HumanEval

OpenAI's benchmark for evaluating code generation

Curated

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Persimmon

Research-preview model that simulates how people behave in chats

CuratedWeb

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Ragas

Evaluation framework for RAG pipelines

Curated

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M

MMLU

Massive Multitask Language Understanding benchmark

Curated

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More in Observability & Evals

Langfuse

Open-source LLM engineering platform for tracing and evals

Curated

1 use thisCompare with LangSmith
AgentOps

Observability and debugging platform purpose-built for AI agents

Curated

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Helicone

Open-source LLM observability and proxy

Curated

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Laminar

Open-source platform to trace, evaluate, and debug AI agents

CuratedWeb

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Opik

Open-source LLM evaluation and tracing by Comet

Curated

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Phoenix (Arize)

Open-source AI observability and evaluation platform

Curated

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Traceloop

OpenTelemetry-based LLM observability

Curated

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Arize AI

ML observability and monitoring platform

CuratedWeb

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Evidently

ML model monitoring and data quality checks

Curated

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Fiddler AI

ML model performance management

Curated

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WhyLabs

Discontinued AI observability platform; platform and whylogs open sourced

Curated

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Captum

Model interpretability library for PyTorch

Curated

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ELI5

Debug and explain ML classifiers and regressors

Curated

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InterpretML

Microsoft's toolkit for model interpretability

Curated

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SHAP

Game theoretic approach to explain ML model outputs

Curated

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Guidance

Constrained generation and prompt control by Microsoft

Curated

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Questions

What are the closest alternatives to LangSmith?

Braintrust, DeepEval and EleutherAI LM Evaluation Harness sit on the same sub-line as LangSmith (LLM Evaluation & Benchmarking) on AI Landscape, with 5 more.

How are these alternatives chosen?

They are the other products on the Observability & Evals stop of the map: curated products first, the ones on LangSmith's sub-line before the rest, then by name until members have marked enough of them.