langflow/docs/versioned_docs/version-1.9.0/Components/parser.mdx

---
title: Parser
slug: /parser
---

import Icon from "@site/src/components/icon";
import Tabs from '@theme/Tabs';
import TabItem from '@theme/TabItem';
import PartialParams from '@site/docs/_partial-hidden-params.mdx';
import PartialCurlyBraces from '@site/docs/_partial-escape-curly-braces.mdx';

The **Parser** component extracts text from structured data (`Table` or `JSON`) 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:

* [**Batch Run** component example](/batch-run)
* [**Structured Output** component example](/structured-output)
* **Financial Report Parser** template
* [Trigger flows with webhooks](/webhook)
* [Create a vector RAG chatbot](/chat-with-rag)

![A flow that uses a Parser component to extract text from a Structured Output component.](/img/component-parser.png)

## Parsing modes

The **Parser** component has two modes: **Parser** and **Stringify**.

<Tabs>
<TabItem value="template" label="Parser (template) mode" default>

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 `Table` or `JSON` input, such as column names.
For example, `{name}` extracts the value of a `name` key.
For more information about the content and structure of `Table` and `JSON` objects, see [Langflow data types](/data-types).

<PartialCurlyBraces />

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

<details>
<summary>Employee summary template</summary>

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

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

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

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

</details>

<details>
<summary>Employee profile template</summary>

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

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

When the flow runs, the **Parser** component iterates over each row of the `Table`, populating the template's variables with the appropriate extracted values.
The resulting text for each row is output as a [`Message`](/data-types#message).

</details>

The following parameters are available in **Parser** mode.
<PartialParams />

| Name | Display Name | Info |
|------|--------------|------|
| input_data | JSON or Table | Input parameter. The `JSON` or `Table` input to parse. |
| pattern | Template | Input parameter. The formatting template using plaintext and variables for keys (`{KEY_NAME}`). See the preceding examples for more information. |
| sep | Separator | Input parameter. A string defining the separator for rows or lines. Default: `\n` (new line). |
| clean_data | Clean Data | Whether to remove empty rows and lines in each cell or key of the `Table` or `JSON` input. Default: Enabled (`true`) |

</TabItem>
<TabItem value="stringify" label="Stringify mode">

Use **Stringify** mode to convert the entire input directly to text.
This mode doesn't support templates or key selection.

The following parameters are available in **Stringify** mode.
<PartialParams />

| Name | Display Name | Info |
|------|--------------|------|
| input_data | JSON or Table | Input parameter. The `JSON` or `Table` input to parse. |
| sep | Separator | Input parameter. A string defining the separator for rows or lines. Default: `\n` (new line). |
| clean_data | Clean Data | Whether to remove empty rows and lines in each cell or key of the `Table` or `JSON` input. Default: Enabled (`true`) |

</TabItem>
</Tabs>

## Test and troubleshoot parsed text

To test the **Parser** component, click <Icon name="Play" aria-hidden="true"/> **Run component**, and then click <Icon name="TextSearch" aria-hidden="true"/> **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 `Table`:

```text
{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`:

```text
 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 `JSON` or `Table`.
To see the data being passed directly to the **Parser** component, click <Icon name="TextSearch" aria-hidden="true"/> **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 [**JSON Operations** component](/data-operations), [**Structured Output** component](/structured-output), and [**Smart Transform** component](/smart-transform).
    * Enable the **Parser** component's **Clean Data** parameter to skip empty rows or lines.