Client API Overview

The Client class provides programmatic access to the LangSmith platform. This page provides an overview and links to detailed sections.

Overview

The Client class provides methods for:

• Client Construction & Configuration - Create and configure clients
• Project Management - Manage projects and sessions
• Run Management - Create, query, and manage runs
• Dataset Operations - Create and manage datasets
• Example Management - Manage examples within datasets
• Feedback Operations - Collect and analyze feedback
• Prompt Management - Version control prompts

Quick Start

import { Client } from "langsmith";

// Create client (uses environment variables)
const client = new Client();

// Create client with explicit configuration
const client = new Client({
  apiUrl: "https://api.smith.langchain.com",
  apiKey: process.env.LANGCHAIN_API_KEY,
  timeout_ms: 10000
});

API Sections

Client Core

Client Construction & Configuration

Client setup, configuration options, and utility methods:

• Constructor and configuration
• Default configuration
• Privacy controls
• Batching and performance settings

Project Operations

Project Management

Organize traces into projects:

• Create, read, update, delete projects
• List and filter projects
• Project URLs
• Check existence

Run Operations

Run Management

Manage traces and execution data:

• Create and update runs
• List and filter runs
• Advanced filtering
• Share runs
• Get run statistics

Dataset Operations

Dataset Management

Create and manage test datasets:

• Create, read, update, delete datasets
• Dataset versioning
• Dataset sharing
• Compare versions
• CSV upload

Example Operations

Example Management

Manage examples within datasets:

• Create and update examples
• Bulk operations
• List and filter examples
• Multipart upload
• Similarity search

Feedback Operations

Feedback Collection

Collect and analyze feedback:

• Create and update feedback
• List and filter feedback
• Presigned feedback tokens
• Evaluation feedback logging

Prompt Operations

Prompt Management

Version control and share prompts:

• Create and delete prompts
• Push and pull prompt versions
• List commits
• Like/unlike prompts
• Check existence

Type Reference

Type Definitions

Complete TypeScript type definitions for all entities.

Common Patterns

Client Lifecycle

import { Client } from "langsmith";

const client = new Client();

// Use client for operations
await client.createProject({ projectName: "my-project" });

// Ensure traces are uploaded
await client.awaitPendingTraceBatches();

// Cleanup resources
client.cleanup();

Error Handling

import { Client } from "langsmith";

const client = new Client();

try {
  const run = await client.readRun(runId);
} catch (error) {
  if (error.status === 404) {
    console.error("Run not found");
  } else if (error.status === 401) {
    console.error("Authentication failed");
  } else {
    console.error("API error:", error.message);
  }
}

Pagination

// Async iteration handles pagination automatically
for await (const run of client.listRuns({
  projectName: "my-project",
  limit: 100
})) {
  console.log(run.name);
}

Related Documentation

• Quick Reference - Common code patterns
• Core Concepts - Understanding key concepts
• Tracing Guide - Tracing with Client
• Evaluation Guide - Evaluation workflows