Keywords AI

LangSmith vs Weights & Biases

Compare LangSmith and Weights & Biases side by side. Both are tools in the Observability, Prompts & Evals category.

Quick Comparison

	LangSmith	Weights & Biases
Category	Observability, Prompts & Evals	Observability, Prompts & Evals
Pricing	Freemium	Freemium
Best For	LangChain developers who need integrated tracing, evaluation, and prompt management	ML engineers and researchers who need comprehensive experiment tracking
Website	smith.langchain.com	wandb.ai
Key Features	Trace visualization for LLM chains Prompt versioning and management Evaluation and testing suite Dataset management Tight LangChain integration	ML experiment tracking Model and dataset versioning Collaborative dashboards Sweeps for hyperparameter tuning Prompt monitoring and evaluation
Use Cases	Debugging LangChain and LangGraph applications Prompt iteration and A/B testing LLM output evaluation and scoring Team collaboration on prompt engineering Regression testing for LLM apps	ML experiment tracking and comparison Model training run management Team collaboration on ML projects Hyperparameter optimization Model registry and versioning

When to Choose LangSmith vs Weights & Biases

Choose LangSmith if you need

Debugging LangChain and LangGraph applications
Prompt iteration and A/B testing
LLM output evaluation and scoring

Pricing: Freemium

Choose Weights & Biases if you need

ML experiment tracking and comparison
Model training run management
Team collaboration on ML projects

Pricing: Freemium

About LangSmith

LangSmith is LangChain's observability and evaluation platform for LLM applications. It provides detailed tracing of every LLM call, chain execution, and agent step—showing inputs, outputs, latency, token usage, and cost. LangSmith includes annotation queues for human feedback, dataset management for evaluation, and regression testing for prompt changes. It's the most comprehensive debugging tool for LangChain-based applications.

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About Weights & Biases

Weights & Biases (W&B) is the leading experiment tracking and ML operations platform, now extended to LLM applications. W&B Traces provides observability for LLM pipelines, while W&B Weave offers evaluation and production monitoring. The platform also supports model training tracking, hyperparameter sweeps, and artifact management, making it a comprehensive MLOps solution.

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What is Observability, Prompts & Evals?

Tools for monitoring LLM applications in production, managing and versioning prompts, and evaluating model outputs. Includes tracing, logging, cost tracking, prompt engineering platforms, automated evaluation frameworks, and human annotation workflows.

Browse all Observability, Prompts & Evals tools →