langflow/docs/docs/Concepts/concepts-components.md

title	slug
Components	/concepts-components

import Icon from "@site/src/components/icon";

Langflow components overview

A component is a single building block within a flow with inputs, outputs, functions, and parameters that define its functionality. A single component is like a class within a larger application.

To add a component to a flow, drag it from the Component menu to the Workspace.

Learn more about components and how they work on this page.

Component menu

Each component is unique, but all have a menu bar at the top that looks something like the following:

<img src="/img/openai-model-component.png" alt="Open AI component" style={{display: 'block', margin: 'auto', width: 300}} />

Use the component controls to do the following:

• Code — Modify the component's Python code and save your changes.
• Controls — Adjust all component parameters.
• Freeze Path — After a component runs, lock its previous output state to prevent it from re-running.

Click  All to see additional options for a component.

To view a component’s output and logs, click the Visibility icon.

To run a single component, click Play.

A Checkmark indicates that the component ran successfully.

Running a single component with the Play button is different from running the entire flow. In a single component run, the build_vertex function is called, which builds and runs only the single component with direct inputs provided through the UI (the inputs_dict parameter). The VertexBuildResult data is passed to the build_and_run method, which calls the component's build method and runs it. Unlike running the full flow, running a single component does not automatically execute its upstream dependencies.

Component ports

Handles () on the side of a component indicate the types of inputs and outputs that can be connected at that port. Hover over a handle to see connection details.

<img src="/img/prompt-component.png" alt="Prompt component" style={{display: 'block', margin: 'auto', width: 300}} />

Component port data type colors

The following table lists the handle colors and their corresponding data types:

Data type	Handle color	Hex code
BaseLanguageModel	Fuchsia	#c026d3
Data	Red	#dc2626
Document	Lime	#65a30d
Embeddings	Emerald	#10b981
LanguageModel	Fuchsia	#c026d3
Message	Indigo	#4f46e5
Prompt	Violet	#7c3aed
str	Indigo	#4F46E5
Text	Indigo	#4F46E5
unknown	Gray	#9CA3AF

Component code

A component inherits from a base Component class that defines its interface and behavior.

For example, the Recursive character text splitter is a child of the LCTextSplitterComponent class.

from typing import Any

from langchain_text_splitters import RecursiveCharacterTextSplitter, TextSplitter

from langflow.base.textsplitters.model import LCTextSplitterComponent
from langflow.inputs.inputs import DataInput, IntInput, MessageTextInput
from langflow.utils.util import unescape_string

class RecursiveCharacterTextSplitterComponent(LCTextSplitterComponent):
    display_name: str = "Recursive Character Text Splitter"
    description: str = "Split text trying to keep all related text together."
    documentation: str = "https://docs.langflow.org/components-processing"
    name = "RecursiveCharacterTextSplitter"
    icon = "LangChain"

    inputs = [
        IntInput(
            name="chunk_size",
            display_name="Chunk Size",
            info="The maximum length of each chunk.",
            value=1000,
        ),
        IntInput(
            name="chunk_overlap",
            display_name="Chunk Overlap",
            info="The amount of overlap between chunks.",
            value=200,
        ),
        DataInput(
            name="data_input",
            display_name="Input",
            info="The texts to split.",
            input_types=["Document", "Data"],
        ),
        MessageTextInput(
            name="separators",
            display_name="Separators",
            info='The characters to split on.\nIf left empty defaults to ["\\n\\n", "\\n", " ", ""].',
            is_list=True,
        ),
    ]

    def get_data_input(self) -> Any:
        return self.data_input

    def build_text_splitter(self) -> TextSplitter:
        if not self.separators:
            separators: list[str] | None = None
        else:
            # check if the separators list has escaped characters
            # if there are escaped characters, unescape them
            separators = [unescape_string(x) for x in self.separators]

        return RecursiveCharacterTextSplitter(
            separators=separators,
            chunk_size=self.chunk_size,
            chunk_overlap=self.chunk_overlap,
        )

Components include definitions for inputs and outputs, which are represented in the UI with color-coded ports.

Input Definition: Each input (like IntInput or DataInput) specifies an input's type, name, and display properties, which appear as configurable fields in the component's UI panel.

Methods: Components have methods or functions that handle their functionality. This component has two methods. get_data_input retrieves the text data to be split from the component's input. This makes the data available to the class. build_text_splitter creates a RecursiveCharacterTextSplitter object by calling its parent class's build method. The text is split with the created splitter and passed to the next component. When used in a flow, this component:

1. Displays its configuration options in the UI.
2. Validates user inputs based on the input types.
3. Processes data using the configured parameters.
4. Passes results to the next component.

Freeze path

After a component runs, Freeze Path locks the component's previous output state to prevent it from re-running.

If you’re expecting consistent output from a component and don’t need to re-run it, click Freeze Path.

Enabling Freeze Path freezes all components upstream of the selected component.

If you only want to freeze a single component, select Freeze instead.

A icon appears on all frozen components.

Additional component options

Click  All to see additional options for a component.

To modify a component's name or description, double-click in the Name or Description fields. Component descriptions accept Markdown syntax.

Component shortcuts

The following keyboard shortcuts are available when a component is selected.

Menu item	Windows shortcut	Mac shortcut	Description
Code	Space	Space	Opens the code editor for the component.
Advanced Settings	Ctrl + Shift + A	⌘ + Shift + A	Opens advanced settings for the component.
Save Changes	Ctrl + S	⌘ + S	Saves changes to the current flow.
Save Component	Ctrl + Alt + S	⌘ + Alt + S	Saves the current component to Saved components.
Duplicate	Ctrl + D	⌘ + D	Creates a duplicate of the component.
Copy	Ctrl + C	⌘ + C	Copies the selected component.
Cut	Ctrl + X	⌘ + X	Cuts the selected component.
Paste	Ctrl + V	⌘ + V	Pastes the copied/cut component.
Docs	Ctrl + Shift + D	⌘ + Shift + D	Opens related documentation.
Minimize	Ctrl + .	⌘ + .	Minimizes the current component.
Freeze	Ctrl + F	⌘ + F	Freezes the current component state.
Freeze Path	Ctrl + Shift + F	⌘ + Shift + F	Freezes component state and upstream components.
Download	Ctrl + J	⌘ + J	Downloads the component as JSON.
Delete	Backspace	Backspace	Deletes the component.
Group	Ctrl + G	⌘ + G	Groups selected components.
Undo	Ctrl + Z	⌘ + Z	Undoes the last action.
Redo	Ctrl + Y	⌘ + Y	Redoes the last undone action.
Redo (alternative)	Ctrl + Shift + Z	⌘ + Shift + Z	Alternative shortcut for redo.
Share Component	Ctrl + Shift + S	⌘ + Shift + S	Shares the component.
Share Flow	Ctrl + Shift + B	⌘ + Shift + B	Shares the entire flow.
Toggle Sidebar	Ctrl + B	⌘ + B	Shows/hides the sidebar.
Search Components	/	/	Focuses the component search bar.
Tool Mode	Ctrl + Shift + M	⌘ + Shift + M	Toggles tool mode.
Update	Ctrl + U	⌘ + U	Updates the component.
Open Playground	Ctrl + K	⌘ + K	Opens the playground.
Output Inspection	O	O	Opens output inspection.
Play	P	P	Plays/executes the flow.
API	R	R	Opens the API view.

Group components in the workspace

Multiple components can be grouped into a single component for reuse. This is useful when combining large flows into single components, for example RAG with a vector database, and saving space.

1. Hold Shift and drag to select components.
2. Select Group. The components merge into a single component.
3. Double-click the name and description to change them.
4. Save your grouped component to the sidebar for later use.

Component version

A component's initial state is stored in a database. As soon as you drag a component from the sidebar to the workspace, the two components are no longer in parity.

A component keeps the version number it is initialized to the workspace with. If a component is at version 1.0 when it is dragged to the workspace, it will stay at version 1.0 until you update it.

Langflow notifies you when a component's workspace version is behind the database version and an update is available. Click the Update Component icon to update the component to the latest version. This will change the code of the component in place so you can validate that the component was updated by checking its Python code before and after updating it.

Components sidebar

Components are listed in the sidebar by component type.

Component bundles are components grouped by provider. For example, Langchain modules like RunnableExecutor and CharacterTextSplitter are grouped under the Langchain bundle.

The sidebar includes a component Search bar, and includes flags for showing or hiding Beta and Legacy components.

Beta components are still being tested and are not suitable for production workloads.

Legacy components are available to use but no longer supported.