---
title: "StringJoiner"
id: stringjoiner
slug: "/stringjoiner"
description: "Component to join strings from different components into a list of strings."
---

# StringJoiner

Component to join strings from different components into a list of strings.

|  |  |
| --- | --- |
| **Most common position in a pipeline** | After at least two other components to join their strings                                       |
| **Mandatory run variables**            | “strings”: Multiple strings from connected components.                                          |
| **Output variables**                   | “strings”: A list of merged strings                                                             |
| **API reference**                      | [Joiners](/reference/joiners-api)                                                                      |
| **GitHub link**                        | https://github.com/deepset-ai/haystack/blob/main/haystack/components/joiners/string_joiner.py |

## Overview

The `StringJoiner` component collects multiple string outputs from various pipeline components and combines them into a single list. This is useful when you need to merge several strings from different parts of a pipeline into a unified output.

## Usage

```python
from haystack.components.joiners import StringJoiner
from haystack.components.builders import PromptBuilder
from haystack.core.pipeline import Pipeline

string_1 = "What's Natural Language Processing?"
string_2 = "What is life?"

pipeline = Pipeline()
pipeline.add_component("prompt_builder_1", PromptBuilder("Builder 1: {{query}}"))
pipeline.add_component("prompt_builder_2", PromptBuilder("Builder 2: {{query}}"))
pipeline.add_component("string_joiner", StringJoiner())

pipeline.connect("prompt_builder_1.prompt", "string_joiner.strings")
pipeline.connect("prompt_builder_2.prompt", "string_joiner.strings")

result = pipeline.run(data={
    "prompt_builder_1": {"query": string_1}, 
    "prompt_builder_2": {"query": string_2}
})

print(result)
```