> For the complete documentation index, see [llms.txt](https://docs.coupler.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.coupler.io/functionality/data-set/combining-data/append-data.md).

# Append data

Coupler.io allows you to fetch data from several sources at the same time, and append them into a unified dataset - all with a single data flow.

Data **APPEND** (former - Data Union; Data Stitching) in Coupler.io terms means merging values for the same data attribute from two or more data sets and placing them under the same column(s) in the destination file. 

{% embed url="<https://www.youtube.com/watch?v=vURbrV8PAow>" %}

### Concept <a href="#concept-v4uui" id="concept-v4uui"></a>

When combining several sources in Append, Coupler.io compiles the list of unique column names from all the sources it’s meant to stitch. It then puts all data under these columns, using their names as identifiers and keeping rows' content as it was in the sources. Here are two examples:

<details>

<summary><strong>Example:</strong> <em>both sources have the same columns</em></summary>

<div align="left"><img src="https://d33v4339jhl8k0.cloudfront.net/docs/assets/57fbf3029033600277a688ab/images/6359656e73d6a22819f06a04/file-yYLQ8zfcto.png" alt="" width="375"></div>

</details>

<details>

<summary><strong>Example:</strong> <em>some columns are the same for both sources, and some are unique per each source</em></summary>

<div align="left"><img src="https://d33v4339jhl8k0.cloudfront.net/docs/assets/57fbf3029033600277a688ab/images/635965ef9171a91e374a46f4/file-VYXwhRpbpw.png" alt="" width="563"></div>

</details>

#### What business cases can data stitching in Append mode solve? <a href="#what-business-cases-can-data-stitching-in-append-mode-solve-daxhi" id="what-business-cases-can-data-stitching-in-append-mode-solve-daxhi"></a>

Here are a few use cases that you may find useful&#x20;

{% hint style="warning" %}
column names should be the same
{% endhint %}

* Stitch the same data entity from several accounts (e.g., Invoices from two different Xero tenants).
* Stitch Google Sheets, Excel, or CSV files from different  GDrive / OneDrive storage.
* Stitch several pages from a JSON source that has small pagination limits.
* Stitch different data entities from the same source (e.g., Invoices, Bills, Payments from QuickBooks Online) to build a custom report.

#### Which sources can be combined with Append? <a href="#which-sources-can-be-combined-with-append-21pbs" id="which-sources-can-be-combined-with-append-21pbs"></a>

Coupler.io does not limit the sources that you can stitch - you can combine all sources that are available in your plan.

Just notice that the Append data combining mode works properly when data sets have the same columns returned. Otherwise, you will get just two data sets in the destination file without any interconnections between them.

{% hint style="success" %}
Looking to combine data by a key value in different data sets? (Say, combine Customers with Invoices using *customer\_id* as a key? Check our Join data combining mode:  [Data Join](/functionality/data-set/combining-data/join-data.md)
{% endhint %}

#### How to Append data? <a href="#how-to-append-data-lhuna" id="how-to-append-data-lhuna"></a>

There are a few simple steps on how to add several sources to your data flow and stitch them together in Append.&#x20;

{% @arcade/embed flowId="POChXccfWtUUCEA2tVQq" url="<https://app.arcade.software/share/POChXccfWtUUCEA2tVQq>" %}

{% stepper %}
{% step %}
After adding the needed sources, go to the "Transformations" step and either select **Append** from the data preview window. Or hit **+ Add transformation** option from the left sidebar, then select **Append**
{% endstep %}

{% step %}
Choose the sources you want to stitch and select the "Append data" option. You may append data from all the sources you added in your data flow, or pick only specific sources
{% endstep %}

{% step %}
The appended data will appear under the dedicated section on the left sidebar
{% endstep %}

{% step %}
Preview the appended data, and make further transformations, if needed. Keep in mind that Append mode stitches data from all selected sources under the same headers (column names), so you may want to adjust your column names to match, where applicable, to have the aligned dataset
{% endstep %}

{% step %}
If no further transformations are needed, proceed to the **Destinations** setup.
{% endstep %}

{% step %}
Add all needed settings for the destination.
{% endstep %}

{% step %}
Proceed to add the schedule.
{% endstep %}

{% step %}
Save and Run the data flow to check the results of data stitching
{% endstep %}
{% endstepper %}


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://docs.coupler.io/functionality/data-set/combining-data/append-data.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.