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This guide covers how to develop and test Agent Server applications locally. The LangGraph CLI provides two commands for local development, each optimized for different stages of your workflow:
  • langgraph dev: A lightweight development server for rapid iteration.
  • langgraph up: A production-like testing environment for validation.
For full reference details, refer to the LangGraph CLI reference page.

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Development

Here’s the typical workflow when building applications:
  1. Daily development: Use langgraph dev for rapid iteration.
  2. Periodic validation: Test major changes with langgraph up.
  3. Pre-deployment check: Run langgraph up --recreate for a fresh build.
  4. Deploy: Push to production via the LangSmith UI or Control Plane API.

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langgraph dev

The langgraph dev command runs a lightweight server directly in your environment, designed for speed and convenience during active development. The key features include:
  • No Docker required: Runs directly in your environment.
  • Hot reloading: Automatically reloads when you change code.
  • Fast startup: Ready in seconds.
  • Built-in Debug Adapter Protocol support: Attach your IDE debugger to the server for line-level breakpoints & debugging.
  • Local storage: State persisted to local directory.
The dev server is tested with the same integration test suite as production to ensure its behavior is the same during development while using minimal resources.
Before you begin, ensure you have:
  • An API key for LangSmith (free to sign up).
  • uv for Python or npx for TypeScript.
1

Create a LangGraph app

Create a new app from the new-langgraph-project-python template or new-langgraph-project-js template. This template demonstrates a single-node application you can extend with your own logic.
Additional templates
If you use langgraph new without specifying a template, you will be presented with an interactive menu that will allow you to choose from a list of available templates.
2

Install dependencies

3

Launch Agent Server