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Processing components

Langflow's Processing components process and transform data within a flow. They have many uses, including:

Prompt Template​

See Prompt Template component.

Batch Run​

The Batch Run component runs a language model over each row of one text column in a DataFrame, and then returns a new DataFrame with the original text and an LLM response. The output contains the following columns:

  • text_input: The original text from the input DataFrame
  • model_response: The model's response for each input
  • batch_index: The 0-indexed processing order for all rows in the DataFrame
  • metadata (optional): Additional information about the processing

Use the Batch Run component in a flow​

If you pass the Batch Run output to a Parser component, you can use variables in the parsing template to reference these keys, such as {text_input} and {model_response}. This is demonstrated in the following example.

A batch run component connected to OpenAI and a Parser

  1. Connect a Language Model component to a Batch Run component's Language model port.

  2. Connect DataFrame output from another component to the Batch Run component's DataFrame input. For example, you could connect a File component with a CSV file.

  3. In the Batch Run component's Column Name field, enter the name of the column in the incoming DataFrame that contains the text to process. For example, if you want to extract text from a name column in a CSV file, enter name in the Column Name field.

  4. Connect the Batch Run component's Batch Results output to a Parser component's DataFrame input.

  5. Optional: In the Batch Run component's header menu, click Controls, enable the System Message parameter, click Close, and then enter an instruction for how you want the LLM to process each cell extracted from the file. For example, Create a business card for each name.

  6. In the Parser component's Template field, enter a template for processing the Batch Run component's new DataFrame columns (text_input, model_response, and batch_index):

    For example, this template uses three columns from the resulting, post-batch DataFrame:


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    record_number: {batch_index}, name: {text_input}, summary: {model_response}

  7. To test the processing, click the Parser component, click Run component, and then click Inspect output to view the final DataFrame.

    You can also connect a Chat Output component to the Parser component if you want to see the output in the Playground.

Batch Run parameters​

Some parameters are hidden by default in the visual editor. You can modify all parameters through the Controls in the component's header menu.

NameTypeDescription
modelHandleInputInput parameter. Connect the 'Language Model' output from a Language Model component. Required.
system_messageMultilineInputInput parameter. A multi-line system instruction for all rows in the DataFrame.
dfDataFrameInputInput parameter. The DataFrame whose column is treated as text messages, as specified by 'column_name'. Required.
column_nameMessageTextInputInput parameter. The name of the DataFrame column to treat as text messages. If empty, all columns are formatted in TOML.
output_column_nameMessageTextInputInput parameter. Name of the column where the model's response is stored. Default=model_response.
enable_metadataBoolInputInput parameter. If True, add metadata to the output DataFrame.
batch_resultsDataFrameOutput parameter. A DataFrame with all original columns plus the model's response column.

Data Operations​

The Data Operations component performs operations on Data objects, including extracting, filtering, and editing keys and values in the Data. For all options, see Available data operations. The output is a new Data object containing the modified data after running the selected operation.

Use the Data Operations component in a flow​

The following example demonstrates how to use a Data Operations component in a flow using data from a webhook payload:

  1. Create a flow with a Webhook component and a Data Operations component, and then connect the Webhook component's output to the Data Operations component's Data input.

    All operations in the Data Operations component require at least one Data input from another component. If the preceding component doesn't produce Data output, you can use another component, such as the Type Convert component, to reformat the data before passing it to the Data Operations component. Alternatively, you could consider using a component that is designed to process the original data type, such as the Parser or DataFrame Operations components.

  2. In the Operations field, select the operation you want to perform on the incoming Data. For this example, select the Select Keys operation.

    tip

    You can select only one operation. If you need to perform multiple operations on the data, you can chain multiple Data Operations components together to execute each operation in sequence. For more complex multi-step operations, consider using a component like the Smart Function component.

  3. Under Select Keys, add keys for name, username, and email. Click Add more to add a field for each key.

    For this example, assume that the webhook will receive consistent payloads that always contain name, username, and email keys. The Select Keys operation extracts the value of these keys from each incoming payload.

  4. Optional: If you want to view the output in the Playground, connect the Data Operations component's output to a Chat Output component.

    A flow with Webhook, Data Operations, and Chat Output components

  5. To test the flow, send the following request to your flow's webhook endpoint. For more information about the webhook endpoint, see Trigger flows with webhooks.


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    curl -X POST "http://$LANGFLOW_SERVER_URL/api/v1/webhook/$FLOW_ID" \
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    -H "Content-Type: application/json" \
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    -H "x-api-key: $LANGFLOW_API_KEY" \
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    -d '{
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    "id": 1,
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    "name": "Leanne Graham",
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    "username": "Bret",
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    "email": "Sincere@april.biz",
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    "address": {
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    "street": "Main Street",
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    "suite": "Apt. 556",
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    "city": "Springfield",
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    "zipcode": "92998-3874",
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    "geo": {
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    "lat": "-37.3159",
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    "lng": "81.1496"
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    }
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    },
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    "phone": "1-770-736-8031 x56442",
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    "website": "hildegard.org",
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    "company": {
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    "name": "Acme-Corp",
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    "catchPhrase": "Multi-layered client-server neural-net",
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    "bs": "harness real-time e-markets"
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    }
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    }'

  6. To view the Data resulting from the Select Keys operation, do one of the following:

    • If you attached a Chat Output component, open the Playground to see the result as a chat message.
    • Click Inspect output on the Data Operations component.

Data Operations parameters​

Many parameters are conditional based on the selected Operation (operation).

NameDisplay NameInfo
dataDataInput parameter. The Data object to operate on.
operationOperationInput parameter. The operation to perform on the data. See Available data operations
select_keys_inputSelect KeysInput parameter. A list of keys to select from the data.
filter_keyFilter KeyInput parameter. The key to filter by.
operatorComparison OperatorInput parameter. The operator to apply for comparing values.
filter_valuesFilter ValuesInput parameter. A list of values to filter by.
append_update_dataAppend or UpdateInput parameter. The data to append or update the existing data with.
remove_keys_inputRemove KeysInput parameter. A list of keys to remove from the data.
rename_keys_inputRename KeysInput parameter. A list of keys to rename in the data.

Available data operations​

Options for the operations input parameter are as follows. All operations act on an incoming Data object.

NameRequired InputsProcess
Select Keysselect_keys_inputSelects specific keys from the data.
Literal EvalNoneEvaluates string values as Python literals.
CombineNoneCombines multiple data objects into one.
Filter Valuesfilter_key, filter_values, operatorFilters data based on key-value pair.
Append or Updateappend_update_dataAdds or updates key-value pairs.
Remove Keysremove_keys_inputRemoves specified keys from the data.
Rename Keysrename_keys_inputRenames keys in the data.

DataFrame Operations​

The DataFrame Operations component performs operations on DataFrame (table) rows and columns, including schema changes, record changes, sorting, and filtering. For all options, see DataFrame Operations parameters.

The output is a new DataFrame containing the modified data after running the selected operation.

Use the DataFrame Operations component in a flow​

The following steps explain how to configure a DataFrame Operations component in a flow. You can follow along with an example or use your own flow. The only requirement is that the preceding component must create DataFrame output that you can pass to the DataFrame Operations component.

  1. Create a new flow or use an existing flow.

    Example: API response extraction flow

    The following example flow uses five components to extract Data from an API response, transform it to a DataFrame, and then perform further processing on the tabular data using a DataFrame Operations component. The sixth component, Chat Output, is optional in this example. It only serves as a convenient way for you to view the final output in the Playground, rather than inspecting the component logs.

    A flow that ingests an API response, extracts it to a DataFrame with a Smart Function component, and the processes it through a DataFrame Operations component

    If you want to use this example to test the DataFrame Operations component, do the following:

    1. Create a flow with the following components:

      • API Request
      • Language Model
      • Smart Function
      • Type Convert

    2. Configure the Smart Function component and its dependencies:

      • API Request: Configure the API Request component to get JSON data from an endpoint of your choice, and then connect the API Response output to the Smart Function component's Data input.
      • Language Model: Select your preferred provider and model, and then enter a valid API key. Change the output to Language Model, and then connect the LanguageModel output to the Smart Function component's Language Model input.
      • Smart Function: In the Instructions field, enter natural language instructions to extract data from the API response. Your instructions depend on the response content and desired outcome. For example, if the response contains a large result field, you might provide instructions like explode the result field out into a Data object.

    3. Convert the Smart Function component's Data output to DataFrame:

      1. Connect the Filtered Data output to the Type Convert component's Data input.
      2. Set the Type Convert component's Output Type to DataFrame.

    Now the flow is ready for you to add the DataFrame Operations component.

  2. Add a DataFrame Operations component to the flow, and then connect DataFrame output from another component to the DataFrame input.

    All operations in the DataFrame Operations component require at least one DataFrame input from another component. If a component doesn't produce DataFrame output, you can use another component, such as the Type Convert component, to reformat the data before passing it to the DataFrame Operations component. Alternatively, you could consider using a component that is designed to process the original data type, such as the Parser or Data Operations components.

    If you are following along with the example flow, connect the Type Convert component's DataFrame Output port to the DataFrame input.

  3. In the Operations field, select the operation you want to perform on the incoming DataFrame. For example, the Filter operation filters the rows based on a specified column and value.

    tip

    You can select only one operation. If you need to perform multiple operations on the data, you can chain multiple DataFrame Operations components together to execute each operation in sequence. For more complex multi-step operations, like dramatic schema changes or pivots, consider using an LLM-powered component, like the Structured Output or Smart Function component, as a replacement or preparation for the DataFrame Operations component.

    If you're following along with the example flow, select any operation that you want to apply to the data that was extracted by the Smart Function component. To view the contents of the incoming DataFrame, click Run component on the Type Convert component, and then Inspect output. If the DataFrame seems malformed, click Inspect output on each upstream component to determine where the error occurs, and then modify your flow's configuration as needed. For example, if the Smart Function component didn't extract the expected fields, modify your instructions or verify that the given fields are present in the API Response output.

  4. Configure the operation's parameters. The specific parameters depend on the selected operation. For example, if you select the Filter operation, you must define a filter condition using the Column Name, Filter Value, and Filter Operator parameters. For more information, see DataFrame Operations parameters

  5. To test the flow, click Run component on the DataFrame Operations component, and then click Inspect output to view the new DataFrame created from the Filter operation.

    If you want to view the output in the Playground, connect the DataFrame Operations component's output to a Chat Output component, rerun the DataFrame Operations component, and then click Playground.

For another example, see Conditional looping.

DataFrame Operations parameters​

Most DataFrame Operations parameters are conditional because they only apply to specific operations.

The only permanent parameters are DataFrame (df), which is the DataFrame input, and Operation (operation), which is the operation to perform on the DataFrame. Once you select an operation, the conditional parameters for that operation appear on the DataFrame Operations component.

The Add Column operation allows you to add a new column to the DataFrame with a constant value.

The parameters are New Column Name (new_column_name) and New Column Value (new_column_value).

LLM Router​

The LLM Router component routes requests to the most appropriate LLM based on OpenRouter model specifications.

To use the component in a flow, you connect multiple Language Model components to the LLM Router components. One model is the judge LLM that analyzes input messages to understand the evaluation context, selects the most appropriate model from the other attached LLMs, and then routes the input to the selected model. The selected model processes the input, and then returns the generated response.

The following example flow has three Language Model components. One is the judge LLM, and the other two are in the LLM pool for request routing. The Chat Input and Chat Output components create a seamless chat interaction where you send a message and receive a response without any user awareness of the underlying routing.

LLM Router component

LLM Router parameters​

Some parameters are hidden by default in the visual editor. You can modify all parameters through the Controls in the component's header menu.

NameDisplay NameInfo
modelsLanguage ModelsInput parameter. Connect LanguageModel output from multiple Language Model components to create a pool of models. The judge_llm selects models from this pool when routing requests. The first model you connect is the default model if there is a problem with model selection or routing.
input_valueInputInput parameter. The incoming query to be routed to the model selected by the judge LLM.
judge_llmJudge LLMInput parameter. Connect LanguageModel output from one Language Model component to serve as the judge LLM for request routing.
optimizationOptimizationInput parameter. Set a preferred characteristic for model selection by the judge LLM. The options are quality (highest response quality), speed (fastest response time), cost (most cost-effective model), or balanced (equal weight for quality, speed, and cost). Default: balanced
use_openrouter_specsUse OpenRouter SpecsInput parameter. Whether to fetch model specifications from the OpenRouter API.
If false, only the model name is provided to the judge LLM. Default: Enabled (true)
timeoutAPI TimeoutInput parameter. Set a timeout duration in seconds for API requests made by the router. Default: 10
fallback_to_firstFallback to First ModelInput parameter. Whether to use the first LLM in models as a backup if routing fails to reach the selected model. Default: Enabled (true)

LLM Router outputs​

The LLM Router component provides three output options. You can set the desired output type near the component's output port.

  • Output: A Message containing the response to the original query as generated by the selected LLM. Use this output for regular chat interactions.

  • Selected Model Info: A Data object containing information about the selected model, such as its name and version.

  • Routing Decision: A Message containing the judge model's reasoning for selecting a particular model, including input query length and number of models considered. For example:


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    Model Selection Decision:
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    - Selected Model Index: 0
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    - Selected Langflow Model Name: gpt-4o-mini
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    - Selected API Model ID (if resolved): openai/gpt-4o-mini
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    - Optimization Preference: cost
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    - Input Query Length: 27 characters (~5 tokens)
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    - Number of Models Considered: 2
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    - Specifications Source: OpenRouter API

    This is useful for debugging if you feel the judge model isn't selecting the best model.

Parser​

The Parser component extracts text from structured data (DataFrame or Data) using a template or direct stringification. The output is a Message containing the parsed text.

This is a versatile component for data extraction and manipulation in your flows. For examples of Parser components in flows, see the following:

A flow that uses a Parser component to extract text from a Structured Output component.

Parsing modes​

The Parser component has two modes: Parser and Stringify.

In Parser mode, you create a template for text output that can include literal strings and variables for extracted keys.

Use curly braces to define variables anywhere in the template. Variables must match keys in the DataFrame or Data input, such as column names. For example, {name} extracts the value of a name key. For more information about the content and structure of DataFrame and Data objects, see Langflow data types.

When the flow runs, the Parser component iterates over the input, producing a Message for each parsed item. For example, parsing a DataFrame creates a Message for each row, populated with the unique values from that row.

Employee summary template

This example template extracts employee data into a natural language summary about an employee's hire date and current role:


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{employee_first_name} {employee_last_name} was hired on {start_date}.
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Their current position is {job_title} ({grade}).

The resulting Message output replaces the variables with the corresponding extracted values. For example:


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Renlo Kai was hired on 11-July-2017.
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Their current position is Software Engineer (Principal).

Employee profile template

This example template uses Markdown syntax and extracted employee data to create an employee profile:


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# Employee Profile
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## Personal Information
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- **Name:** {name}
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- **ID:** {id}
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- **Email:** {email}

When the flow runs, the Parser component iterates over each row of the DataFrame, populating the template's variables with the appropriate extracted values. The resulting text for each row is output as a Message.

The following parameters are available in Parser mode.

Some parameters are hidden by default in the visual editor. You can modify all parameters through the Controls in the component's header menu.

NameDisplay NameInfo
input_dataData or DataFrameInput parameter. The Data or DataFrame input to parse.
patternTemplateInput parameter. The formatting template using plaintext and variables for keys ({KEY_NAME}). See the preceding examples for more information.
sepSeparatorInput parameter. A string defining the separator for rows or lines. Default: \n (new line).
clean_dataClean DataWhether to remove empty rows and lines in each cell or key of the DataFrame or Data input. Default: Enabled (true)

Test and troubleshoot parsed text​

To test the Parser component, click Run component, and then click Inspect output to see the Message output with the parsed text. You can also connect a Chat Output component if you want to view the output in the Playground.

If the Message output from the Parser component has empty or unexpected values, there might be a mapping error between the input and the parsing mode, the input has empty values, or the input isn't suitable for plaintext extraction.

For example, assume you use the following template to parse a DataFrame:


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{employee_first_name} {employee_last_name} is a {job_title} ({grade}).

The following Message could result from parsing a row where employee_first_name was empty and grade was null:


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Smith is a Software Engineer (null).

To troubleshoot missing or unexpected values, you can do the following:

  • Make sure the variables in your template map to keys in the incoming Data or DataFrame. To see the data being passed directly to the Parser component, click Inspect output on the component that is sending data to the Parser component.

  • Check the source data for missing or incorrect values. There are several ways you can address these inconsistencies:

    • Rectify the source data directly.
    • Use other components to amend or filter anomalies before passing the data to the Parser component. There are many components you can use for this depending on your goal, such as the Data Operations, Structured Output, and Smart Function components.
    • Enable the Parser component's Clean Data parameter to skip empty rows or lines.

Python Interpreter​

This component allows you to execute Python code with imported packages.

The Python Interpreter component can only import packages that are already installed in your Langflow environment. If you encounter an ImportError when trying to use a package, you need to install it first.

To install custom packages, see Install custom dependencies.

Use the Python Interpreter in a flow​

  1. To use this component in a flow, in the Global Imports field, add the packages you want to import as a comma-separated list, such as math,pandas. At least one import is required.
  2. In the Python Code field, enter the Python code you want to execute. Use print() to see the output.
  3. Optional: Enable Tool Mode, and then connect the Python Interpreter component to an Agent component as a tool. For example, connect a Python Interpreter component and a Calculator component as tools for an Agent component, and then test how it chooses different tools to solve math problems. Python Interpreter and Calculator components connected to an Agent component
  4. Ask the agent an easier math question. The Calculator tool can add, subtract, multiple, divide, or perform exponentiation. The agent executes the evaluate_expression tool to correctly answer the question.

Result:


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Executed evaluate_expression
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Input:
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{
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"expression": "2+5"
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}
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Output:
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{
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"result": "7"
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}

  1. Give the agent complete Python code. This example creates a Pandas DataFrame table with the imported pandas packages, and returns the square root of the mean squares.

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import pandas as pd
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import math
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# Create a simple DataFrame
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df = pd.DataFrame({
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'numbers': [1, 2, 3, 4, 5],
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'squares': [x**2 for x in range(1, 6)]
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})
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# Calculate the square root of the mean
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result = math.sqrt(df['squares'].mean())
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print(f"Square root of mean squares: {result}")

The agent correctly chooses the run_python_repl tool to solve the problem.

Result:


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Executed run_python_repl
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Input:
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{
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"python_code": "import pandas as pd\nimport math\n\n# Create a simple DataFrame\ndf = pd.DataFrame({\n 'numbers': [1, 2, 3, 4, 5],\n 'squares': [x**2 for x in range(1, 6)]\n})\n\n# Calculate the square root of the mean\nresult = math.sqrt(df['squares'].mean())\nprint(f\"Square root of mean squares: {result}\")"
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}
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Output:
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{
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"result": "Square root of mean squares: 3.3166247903554"
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}

If you don't include the package imports in the chat, the agent can still create the table using pd.DataFrame, because the pandas package is imported globally by the Python Interpreter component in the Global Imports field.

Python Interpreter parameters​

NameTypeDescription
global_importsStringInput parameter. A comma-separated list of modules to import globally, such as math,pandas,numpy.
python_codeCodeInput parameter. The Python code to execute. Only modules specified in Global Imports can be used.
resultsDataOutput parameter. The output of the executed Python code, including any printed results or errors.

Save File​

The Save File component creates a file containing data produced by another component. Several file formats are supported, and you can store files in Langflow storage or the local file system.

To configure the Save File component and use it in a flow, do the following:

  1. Connect DataFrame, Data, or Message output from another component to the Save File component's Input port.

    You can connect the same output to multiple Save File components if you want to create multiple files, save the data in different file formats, or save files to multiple locations.

  2. In File Name, enter a file name and an optional path.

    The File Name parameter controls where the file is saved. It can contain a file name or an entire file path:

    • Default location: If you only provide a file name, then the file is stored in the Langflow data directory. For example,~/Library/Caches/langflow/data on macOS.

    • Subdirectory: To store files in subdirectories, add the path to the File Name parameter. If a given subdirectory doesn't already exist, Langflow automatically creates it. For example, files/my_file creates my_file in /data/files, and it creates the files subdirectory if it doesn't already exist.

    • Absolute or relative path: To store files elsewhere in your environment or local file storage, provide the absolute or relative path to the desired location. For example, ~/Desktop/my_file saves my_file to the desktop.

    Don't include an extension in the file name. If you do, the extension is treated as part of the file name; it has no impact on the File Format parameter.

  3. In the component's header menu, click Controls, select the desired file format, and then click Close.

    The available File Format options depend on the input data type:

    • DataFrame can be saved to CSV (default), Excel (requires openpyxl custom dependency), JSON (fallback default), or Markdown.

    • Data can be saved to CSV, Excel (requires openpyxl custom dependency), JSON (default), or Markdown.

    • Message can be saved to TXT, JSON (default), or Markdown.

    Overwrites allowed

    If you have multiple Save File components, in one or more flows, with the same file name, path, and extension, the file contains the data from the most recent run only. Langflow doesn't block overwrites if a matching file already exists. To avoid unintended overwrites, use unique file names and paths.

  4. To test the Save File component, click Run component, and then click Inspect output to get the filepath where the file was saved.

    The component's literal output is a Message containing the original data type, the file name and extension, and the absolute filepath to the file based on the File Name parameter. For example:


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    DataFrame saved successfully as 'my_file.csv' at /Users/user.name/Library/Caches/langflow/data/my_file.csv

    If the File Name contains a subdirectory or other non-default path, this is reflected in the Message output. For example, a CSV file with the file name ~/Desktop/my_file could produce the following output:


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    DataFrame saved successfully as '/Users/user.name/Desktop/my_file.csv' at /Users/user.name/Desktop/my_file.csv

  5. Optional: If you want to use the saved file in a flow, you must use an API call or another component to retrieve the file from the given filepath.

Smart Function​

In Langflow version 1.5, this component was renamed from Lambda Filter to Smart Function.

The Smart Function component uses an LLM to generate a Lambda function to filter or transform structured data based on natural language instructions. You must connect this component to a Language Model component, which is used to generate a function based on the natural language instructions you provide in the Instructions parameter. The LLM runs the function against the data input, and then outputs the results as Data.

tip

Provide brief, clear instructions, focusing on the desired outcome or specific actions, such as Filter the data to only include items where the 'status' is 'active'. One sentence or less is preferred because end punctuation, like periods, can cause errors or unexpected behavior.

If you need to provide more details instructions that aren't directly relevant to the Lambda function, you can input them in the Language Model component's Input field or through a Prompt Template component.

The following example uses the API Request endpoint to pass JSON data from the https://jsonplaceholder.typicode.com/users endpoint to the Smart Function component. Then, the Smart Function component passes the data and the instruction extract emails to the attached Language Model component. From there, the LLM generates a filter function that extracts email addresses from the JSON data, returning the filtered data as chat output.

A small flow using a Smart Function component to extract data from an API response.

Smart Function parameters​

Some parameters are hidden by default in the visual editor. You can modify all parameters through the Controls in the component's header menu.

NameDisplay NameInfo
dataDataInput parameter. The structured data to filter or transform using a Lambda function.
llmLanguage ModelInput parameter. Connect LanguageModel output from a Language Model component.
filter_instructionInstructionsInput parameter. The natural language instructions for how to filter or transform the data. The LLM uses these instructions to create a Lambda function.
sample_sizeSample SizeInput parameter. For large datasets, the number of characters to sample from the dataset head and tail. Only applied if the dataset meets or exceeds max_size. Default: 1000.
max_sizeMax SizeInput parameter. The number of characters for the dataset to be considered large, which triggers sampling by the sample_size value. Default: 30000.

Split Text​

The Split Text component splits data into chunks based on parameters like chunk size and separator. It is often used to chunk data to be tokenized and embedded into vector databases. For examples, see Use Vector Store components in a flow, Use Embedding Model components in a flow, and Create a Vector RAG chatbot.

An embedding generation flow that uses a Split Text component to chunk data.

The component accepts Message, Data, or DataFrame, and then outputs either Chunks or DataFrame. The Chunks output returns a list of Data objects containing individual text chunks. The DataFrame output returns the list of chunks as a structured DataFrame with additional text and metadata columns.

Split Text parameters​

The Split Text component's parameters control how the text is split into chunks, specifically the chunk_size, chunk_overlap, and separator parameters.

To test the chunking behavior, add a Text Input or File component with some sample data to chunk, click Run component on the Split Text component, and then click Inspect output to view the list of chunks and their metadata. The text column contains the actual text chunks created from your chunking settings. If the chunks aren't split as you expect, adjust the parameters, rerun the component, and then inspect the new output.

Some parameters are hidden by default in the visual editor. You can modify all parameters through the Controls in the component's header menu.

NameDisplay NameInfo
data_inputsInputInput parameter. The data to split. Input must be in Message, Data, or DataFrame format.
chunk_overlapChunk OverlapInput parameter. The number of characters to overlap between chunks. This helps maintain context across chunks. When a separator is encountered, the overlap is applied at the point of the separator so that the subsequent chunk contains the last n characters of the preceding chunk. Default: 200.
chunk_sizeChunk SizeInput parameter. The target length for each chunk after splitting. The data is first split by separator, and then chunks smaller than the chunk_size are merged up to this limit. However, if the initial separator split produces any chunks larger than the chunk_size, those chunks are neither further subdivided nor combined with any smaller chunks; these chunks will be output as-is even though they exceed the chunk_size. Default: 1000. See Tokenization errors due to chunk size for important considerations.
separatorSeparatorInput parameter. A string defining a character to split on, such as \n to split on new line characters, \n\n to split at paragraph breaks, or }, to split at the end of JSON objects. You can directly provide the separator string, or pass a separator string from another component as Message input.
text_keyText KeyInput parameter. The key to use for the text column that is extracted from the input and then split. Default: text.
keep_separatorKeep SeparatorInput parameter. Select how to handle separators in output chunks. If False, separators are omitted from output chunks. Options include False (remove separators), True (keep separators in chunks without preference for placement), Start (place separators at the beginning of chunks), or End (place separators at the end of chunks). Default: False.

Tokenization errors due to chunk size​

When using Split Text with embedding models (especially NVIDIA models like nvidia/nv-embed-v1), you may need to use smaller chunk sizes (500 or less) even though the model supports larger token limits. The Split Text component doesn't always enforce the exact chunk size you set, and individual chunks may exceed your specified limit. If you encounter tokenization errors, modify your text splitting strategy by reducing the chunk size, changing the overlap length, or using a more common separator. Then, test your configuration by running the flow and inspecting the component's output.

Other text splitters​

See LangChain text splitter components.

Structured Output​

The Structured Output component uses an LLM to transform any input into structured data (Data or DataFrame) using natural language formatting instructions and an output schema definition. For example, you can extract specific details from documents, like email messages or scientific papers.

Use the Structured Output component in a flow​

To use the Structured Output component in a flow, do the following:

  1. Provide an Input Message, which is the source material from which you want to extract structured data. This can come from practically any component, but it is typically a Chat Input, File, or other component that provides some unstructured or semi-structured input.

    tip

    Not all source material has to become structured output. The power of the Structured Output component is that you can specify the information you want to extract, even if that data isn't explicitly labeled or an exact keyword match. Then, the LLM can use your instructions to analyze the source material, extract the relevant data, and format it according to your specifications. Any irrelevant source material isn't included in the structured output.

  2. Define Format Instructions and an Output Schema to specify the data to extract from the source material and how to structure it in the final Data or DataFrame output.

    The instructions are a prompt that tell the LLM what data to extract, how to format it, how to handle exceptions, and any other instructions relevant to preparing the structured data.

    The schema is a table that defines the fields (keys) and data types to organize the data extracted by the LLM into a structured Data or DataFrame object. For more information, see Output Schema options

  3. Attach a Language Model component that is set to emit LanguageModel output.

    The LLM uses the Input Message and Format Instructions from the Structured Output component to extract specific pieces of data from the input text. The output schema is applied to the model's response to produce the final Data or DataFrame structured object.

  4. Optional: Typically, the structured output is passed to downstream components that use the extracted data for other processes, such as the Parser or Data Operations components.

A basic flow with Structured Output, Language Model, Type Convert, and Chat Input and Output components.

Structured Output example: Financial Report Parser template

The Financial Report Parser template provides an example of how the Structured Output component can be used to extract structured data from unstructured text.

The template's Structured Output component has the following configuration:

  • The Input Message comes from a Chat Input component that is preloaded with quotes from sample financial reports

  • The Format Instructions are as follows:


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    You are an AI that extracts structured JSON objects from unstructured text.
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    Use a predefined schema with expected types (str, int, float, bool, dict).
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    Extract ALL relevant instances that match the schema - if multiple patterns exist, capture them all.
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    Fill missing or ambiguous values with defaults: null for missing values.
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    Remove exact duplicates but keep variations that have different field values.
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    Always return valid JSON in the expected format, never throw errors.
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    If multiple objects can be extracted, return them all in the structured format.

  • The Output Schema includes keys for EBITDA, NET_INCOME, and GROSS_PROFIT.

The structured Data object is passed to a Parser component that produces a text string by mapping the schema keys to variables in the parsing template:


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EBITDA: {EBITDA} , Net Income: {NET_INCOME} , GROSS_PROFIT: {GROSS_PROFIT}

When printed to the Playground, the resulting Message replaces the variables with the actual values extracted by the Structured Output component. For example:


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EBITDA: 900 million , Net Income: 500 million , GROSS_PROFIT: 1.2 billion

Structured Output parameters​

Some parameters are hidden by default in the visual editor. You can modify all parameters through the Controls in the component's header menu.

NameTypeDescription
Language Model (llm)LanguageModelInput parameter. The LanguageModel output from a Language Model component that defines the LLM to use to analyze, extract, and prepare the structured output.
Input Message (input_value)StringInput parameter. The input message containing source material for extraction.
Format Instructions (system_prompt)StringInput parameter. The instructions to the language model for extracting and formatting the output.
Schema Name (schema_name)StringInput parameter. An optional title for the Output Schema.
Output Schema (output_schema)TableInput parameter. A table describing the schema of the desired structured output, ultimately determining the content of the Data or DataFrame output. See Output Schema options.
Structured Output (structured_output)Data or DataFrameOutput parameter. The final structured output produced by the component. Near the component's output port, you can select the output data type as either Structured Output Data or Structured Output DataFrame. The specific content and structure of the output depends on the input parameters.

Output Schema options​

After the LLM extracts the relevant data from the Input Message and Format Instructions, the data is organized according to the Output Schema.

The schema is a table that defines the fields (keys) and data types for the final Data or DataFrame output from the Structured Output component.

The default schema is a single field string.

To add a key to the schema, click Add a new row, and then edit each column to define the schema:

  • Name: The name of the output field. Typically a specific key for which you want to extract a value.

    You can reference these keys as variables in downstream components, such as a Parser component's template. For example, the schema key NET_INCOME could be referenced by the variable {NET_INCOME}.

  • Description: An optional metadata description of the field's contents and purpose.

  • Type: The data type of the value stored in the field. Supported types are str (default), int, float, bool, and dict.

  • As List: Enable this setting if you want the field to contain a list of values rather than a single value.

For simple schemas, you might only extract a few string or int fields. For more complex schemas with lists and dictionaries, it might help to refer to the Data and DataFrame structures and attributes, as described in Langflow data types. You can also emit a rough Data or DataFrame, and then use downstream components for further refinement, such as a Data Operations component.

Type Convert​

The Type Convert component converts data from one type to another. It supports Data, DataFrame, and Message data types.

A Data object is a structured object that contains a primary text key and other key-value pairs:


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"data": {
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"text": "User Profile",
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"name": "Charlie Lastname",
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"age": 28,
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"email": "charlie.lastname@example.com"
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},

The larger context associated with a component's data dictionary also identifies which key is the primary text_key, and it can provide an optional default value if the primary key isn't specified. For example:


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{
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"text_key": "text",
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"data": {
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"text": "User Profile",
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"name": "Charlie Lastname",
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"age": 28,
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"email": "charlie.lastname@example.com"
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},
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"default_value": ""
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}

For more information, see Langflow data types.

Use the Type Convert component in a flow​

The Type Convert component is typically used to transform data into a format required by a downstream component. For example, if a component outputs a Message, but the following component requires Data, then you can use the Type Convert component to reformat the Message as Data before passing it to the downstream component.

The following example uses the Type Convert component to convert the DataFrame output from a Web Search component into Message data that is passed as text input for an LLM:

  1. Create a flow based on the Basic prompting template.

  2. Add a Web Search component to the flow, and then enter a search query, such as environmental news.

  3. In the Prompt Template component, replace the contents of the Template field with the following text:


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    Answer the user's question using the {context}

    The curly braces define a prompt variable that becomes an input field on the Prompt Template component. In this example, you will use the context field to pass the search results into the template, as explained in the next steps.

  4. Add a Type Convert component to the flow, and then set the Output Type to Message.

    Because the Web Search component's DataFrame output is incompatible with the context variable's Message input, you must use the Type Convert component to change the DataFrame to a Message in order to pass the search results to the Prompt Template component.

  5. Connect the additional components to the rest of the flow:

    • Connect the Web Search component's output to the Type Convert component's input.
    • Connect the Type Convert component's output to the Prompt Template component's context input.

    Convert web search output to text input

  6. In the Language Model component, add your OpenAI API key.

    If you want to use a different provider or model, edit the Model Provider, Model Name, and API Key fields accordingly.

  7. Click Playground, and then ask something relevant to your search query, such as latest news or what's the latest research on the environment?.

    Result

    The LLM uses the search results context, your chat message, and it's built-in training data to respond to your question. For example:


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    Here are some of the latest news articles related to the environment:
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    Ozone Pollution and Global Warming: A recent study highlights that ozone pollution is a significant global environmental concern, threatening human health and crop production while exacerbating global warming. Read more
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    ...

Type Convert parameters​

NameDisplay NameInfo
input_dataInput DataInput parameter. The data to convert. Accepts Data, DataFrame, or Message input.
output_typeOutput TypeInput parameter. The desired output type, as one of Data, DataFrame or Message.
outputOutputOutput parameter. The converted data in the specified format. The output port changes depending on the selected Output Type.

Legacy Processing components​

The following Processing components are legacy components. You can still use them in your flows, but they are no longer supported and can be removed in a future release.

Replace these components with suggested alternatives as soon as possible.

Alter Metadata

Replace this legacy component with the Data Operations component.

This component modifies metadata of input objects. It can add new metadata, update existing metadata, and remove specified metadata fields. The component works with both Message and Data objects, and can also create a new Data object from user-provided text.

It accepts the following parameters:

NameDisplay NameInfo
input_valueInputInput parameter. Objects to which Metadata should be added.
text_inUser TextInput parameter. Text input; the value is contained in the 'text' attribute of the Data object. Empty text entries are ignored.
metadataMetadataInput parameter. Metadata to add to each object.
remove_fieldsFields to RemoveInput parameter. Metadata fields to remove.
dataDataOutput parameter. List of Input objects, each with added metadata.
Combine Data/Merge Data

Replace this legacy component with the Data Operations component or the Loop component.

This component combines multiple data sources into a single unified Data object.

The component iterates through a list of Data objects, merging them into a single Data object (merged_data). If the input list is empty, it returns an empty data object. If there's only one input data object, it returns that object unchanged.

The merging process uses the addition operator to combine data objects.

Combine Text

Replace this legacy component with the Data Operations component.

This component concatenates two text inputs into a single text chunk using a specified delimiter, outputting a Message object with the combined text.

Create Data

Replace this legacy component with the Data Operations component.

This component dynamically creates a Data object with a specified number of fields and a text key.

It accepts the following parameters:

NameDisplay NameInfo
number_of_fieldsNumber of FieldsInput parameter. The number of fields to be added to the record.
text_keyText KeyInput parameter. Key that identifies the field to be used as the text content.
text_key_validatorText Key ValidatorInput parameter. If enabled, checks if the given Text Key is present in the given Data.
Extract Key

Replace this legacy component with the Data Operations component.

This component extracts a specific key from a Data object and returns the value associated with that key.

Data to DataFrame/Data to Message

Replace these legacy components with newer Processing components, such as the Data Operations component and Type Convert component.

These components converted one or more Data objects into a DataFrame or Message object.

For the Data to DataFrame component, each Data object corresponds to one row in the resulting DataFrame. Fields from the .data attribute become columns, and the .text field (if present) is placed in a text column.

Filter Data

Replace this legacy component with the Data Operations component.

This component filters a Data object based on a list of keys (filter_criteria), returning a new Data object (filtered_data) that contains only the key-value pairs that match the filter criteria.

Filter Values

Replace this legacy component with the Data Operations component.

The Filter values component filters a list of data items based on a specified key, filter value, and comparison operator.

It accepts the following parameters:

NameDisplay NameInfo
input_dataInput dataInput parameter. The list of data items to filter.
filter_keyFilter KeyInput parameter. The key to filter on.
filter_valueFilter ValueInput parameter. The value to filter by.
operatorComparison OperatorInput parameter. The operator to apply for comparing the values.
filtered_dataFiltered dataOutput parameter. The resulting list of filtered data items.
JSON Cleaner

Replace this legacy component with the Parser component.

This component cleans JSON strings to ensure they are fully compliant with the JSON specification.

It accepts the following parameters:

NameDisplay NameInfo
json_strJSON StringInput parameter. The JSON string to be cleaned. This can be a raw, potentially malformed JSON string produced by language models or other sources that may not fully comply with JSON specifications.
remove_control_charsRemove Control CharactersInput parameter. If set to True, this option removes control characters (ASCII characters 0-31 and 127) from the JSON string. This can help eliminate invisible characters that might cause parsing issues or make the JSON invalid.
normalize_unicodeNormalize UnicodeInput parameter. When enabled, this option normalizes Unicode characters in the JSON string to their canonical composition form (NFC). This ensures consistent representation of Unicode characters across different systems and prevents potential issues with character encoding.
validate_jsonValidate JSONInput parameter. If set to True, this option attempts to parse the JSON string to ensure it is well-formed before applying the final repair operation. It raises a ValueError if the JSON is invalid, allowing for early detection of major structural issues in the JSON.
outputCleaned JSON StringOutput parameter. The resulting cleaned, repaired, and validated JSON string that fully complies with the JSON specification.
Message to Data

Replace this legacy component with the Type Convert component.

This component converts Message objects to Data objects.

Parse DataFrame

Replace this legacy component with the DataFrame Operations component or Parser component.

This component converts DataFrame objects into plain text using templates.

It accepts the following parameters:

NameDisplay NameInfo
dfDataFrameInput parameter. The DataFrame to convert to text rows.
templateTemplateInput parameter. Template for formatting (use {column_name} placeholders).
sepSeparatorInput parameter. String to join rows in output.
textTextOutput parameter. All rows combined into single text.
Parse JSON

Replace this legacy component with the Parser component.

This component converts and extracts JSON fields in Message and Data objects using JQ queries, then returns filtered_data, which is a list of Data objects.

Python REPL

Replace this legacy component with the Python Interpreter component or another processing or logic component.

This component creates a Python REPL (Read-Eval-Print Loop) tool for executing Python code.

It accepts the following parameters:

NameTypeDescription
nameStringInput parameter. The name of the tool. Default: python_repl.
descriptionStringInput parameter. A description of the tool's functionality.
global_importsList[String]Input parameter. A list of modules to import globally. Default: math.
toolToolOutput parameter. A Python REPL tool for use in LangChain.
Python Code Structured

Replace this legacy component with the Python Interpreter component or another processing or logic component.

This component creates a structured tool from Python code using a dataclass.

The component dynamically updates its configuration based on the provided Python code, allowing for custom function arguments and descriptions.

It accepts the following parameters:

NameTypeDescription
tool_codeStringInput parameter. The Python code for the tool's dataclass.
tool_nameStringInput parameter. The name of the tool.
tool_descriptionStringInput parameter. The description of the tool.
return_directBooleanInput parameter. Whether to return the function output directly.
tool_functionStringInput parameter. The selected function for the tool.
global_variablesDictInput parameter. Global variables or data for the tool.
result_toolToolOutput parameter. A structured tool created from the Python code.
Regex Extractor

Replace this legacy component with the Parser component.

This component extracts patterns in text using regular expressions. It can be used to find and extract specific patterns or information in text.

Select Data

Replace this legacy component with the Data Operations component.

This component selects a single Data object from a list.

It accepts the following parameters:

NameDisplay NameInfo
data_listData ListInput parameter. List of data to select from
data_indexData IndexInput parameter. Index of the data to select
selected_dataSelected DataOutput parameter. The selected Data object.
Update Data

Replace this legacy component with the Data Operations component.

This component dynamically updates or appends data with specified fields.

It accepts the following parameters:

NameDisplay NameInfo
old_dataDataInput parameter. The records to update.
number_of_fieldsNumber of FieldsInput parameter. The number of fields to add. The maximum is 15.
text_keyText KeyInput parameter. The key for text content.
text_key_validatorText Key ValidatorInput parameter. Validates the text key presence.
dataDataOutput parameter. The updated Data objects.
Search