Langflow overview

This page explores the fundamental building blocks of Langflow, beginning with the question, "What is a flow?"

What is a flow?

A flow is an application. It receives input, processes it, and produces output.

Flows are created in the workspace with components dragged from the components sidebar.

A flow can be as simple as the basic prompting flow, which creates an OpenAI chatbot with four components.

• Each component in a flow is a node that performs a specific task, like an AI model or a data source.
• Each component has a Configuration menu. Click the Code button on a component to see its underlying Python code.
• Components are connected with edges to form flows.

If you're familiar with React Flow, a flow is a node-based application, a component is a node, and the connections between components are edges.

When a flow is run, Langflow builds a Directed Acyclic Graph (DAG) graph object from the nodes (components) and edges (connections between components), with the nodes sorted to determine the order of execution. The graph build calls the individual components' def_build functions to validate and prepare the nodes. This graph is then processed in dependency order. Each node is built and executed sequentially, with results from each built node being passed to nodes that are dependent on the previous node's results.

Flows are stored on local disk at the following default locations:

• Linux and WSL: home/<username>/.cache/langflow/
• macOS: /Users/<username>/Library/Caches/langflow/

The flow storage location can be customized with the LANGFLOW_CONFIG_DIR environment variable.

Find your way around

If you're new to Langflow, it's OK to feel a bit lost at first. We’ll take you on a tour, so you can orient yourself and start creating applications quickly.

Langflow has four distinct regions: the workspace is the main area where you build your flows. The components sidebar is on the left, and lists the available components. The playground and publish pane are available in the upper right corner.

Workspace

The workspace is where you create AI applications by connecting and running components in flows.

• Click and drag the workspace to move it left, right, up, and down.
• Scroll up and down to zoom in and out of the workspace, or use the Zoom In and Zoom Out controls.
• Click Fit To Zoom to center the workspace on the current flow.
• Click Lock to lock the workspace in place, preventing accidental movement.
• Click Add Note to add a note to your flow, similar to commenting in code.

Components

A component is a single building block within a flow and consists of inputs, outputs, and parameters that define its functionality.

To add a component to your flow, drag it from the sidebar onto the workspace.

To connect components, drag a line from the output handle (⚪) of one component to the input handle of another.

For more information, see Components overview.

Playground

The Playground executes the current flow in the workspace.

Chat with your flow, view inputs and outputs, and modify your AI's memories to tune your responses in real time.

Either the Chat Input or Chat Output component can be opened in the Playground and tested in real time.

For more information, see the Playground.

Publish pane

The Publish pane provides code templates to integrate your flows into external applications.

For more information, see the Publish pane.

View logs

The Logs pane provides a detailed record of all component executions within a workspace.

To access the Logs pane, click your Flow Name, and then select Logs.

Langflow stores logs at the location specified in the LANGFLOW_CONFIG_DIR environment variable.

This directory's default location depends on your operating system.

• Linux and WSL: ~/.cache/langflow/
• macOS: /Users/<username>/Library/Caches/langflow/
• Windows: %LOCALAPPDATA%\langflow\langflow\Cache

To modify the location of your log file:

1. Add LANGFLOW_LOG_FILE=path/to/logfile.log in your .env file.
2. To start Langflow with the values from your .env file, start Langflow with uv run langflow run --env-file .env.

An example .env file is available in the project repository.

Projects

The Projects page displays all the flows you've created in the Langflow workspace.

Starter Project is the default space where all new projects are initially stored. To create a new project, click Create new project.

To upload a flow to your project, click Upload a flow.

To delete a flow from your project, click a flow's checkbox to select it, and then click Delete. You can select multiple flows in a single action.

File management

Upload, store, and manage files in Langflow's File management system.

For more on managing your files, see Manage files.

Options menu

The dropdown menu labeled with the project name offers several management and customization options for the current flow in the Langflow workspace:

• New: Create a new flow from scratch.
• Edit Details: Adjust settings specific to the current flow, such as its name, description, and endpoint name.
• Logs: View logs for the current project, including execution history, errors, and other runtime events.
• Import: Import a flow or component from a JSON file into the workspace.
• Export: Export the current flow as a JSON file.
• Undo: Revert the last action taken in the project. Keyboard shortcut: Control+Z (or Command+Z on macOS).
• Redo: Reapply a previously undone action. Keyboard shortcut: Control+Y (or Command+Y on macOS).
• Refresh All: Refresh all components and delete cache.

Settings

Click Settings to access Global variables, Langflow API keys, Shortcuts, and Messages.