# Loop

The **Loop** component repeats a set of actions multiple times within your flow. Use it when you need to iterate over a list of items (such as processing each record from an API response), run a block a fixed number of times, or keep executing while a condition remains true. Fastn supports three loop types: **Loop N times**, **Loop over data**, and **While loop**.

<figure><img src="https://docs.fastn.ai/~gitbook/image?url=https%3A%2F%2F1255842839-files.gitbook.io%2F%7E%2Ffiles%2Fv0%2Fb%2Fgitbook-x-prod.appspot.com%2Fo%2Fspaces%252F3iSr2Tx8FvvuoLPncziH%252Fuploads%252FHp6qLW5glBYyiRkSSOoJ%252Fimage.png%3Falt%3Dmedia%26token%3D8a0aaea8-cbdc-44f4-97cb-74ec3d4b808a&#x26;width=768&#x26;dpr=4&#x26;quality=100&#x26;sign=909a8e72&#x26;sv=2" alt="Loop component with loop type selection and data mapping options"><figcaption></figcaption></figure>

> You can select the Loop Type and the Data you want to loop over, mapping it from previous flow steps.

* **Loop N times**: Run a block a fixed number of times.
* **Loop over data**: Iterate through each item in a list.
* **While loop**: Keep looping as long as a condition is true.

Use **End Loop** to mark where the loop finishes.

In the example shown, the **Loop Type** is set to *Loop over data,* and the **Loop Data** field is mapped from a previous step:

```
{{steps.sendMessage.output.message.blocks}}
```

This means the loop will go through each `block` inside the `message` output from the `sendMessage` step, allowing you to process every block one by one.

<figure><img src="https://docs.fastn.ai/~gitbook/image?url=https%3A%2F%2F1255842839-files.gitbook.io%2F%7E%2Ffiles%2Fv0%2Fb%2Fgitbook-x-prod.appspot.com%2Fo%2Fspaces%252F3iSr2Tx8FvvuoLPncziH%252Fuploads%252FoOe0bAvfenYGPkENLvTj%252Fimage.png%3Falt%3Dmedia%26token%3Dd5e58cec-56b6-463e-9952-e659c4317f8d&#x26;width=768&#x26;dpr=4&#x26;quality=100&#x26;sign=2ac136ef&#x26;sv=2" alt="Loop configured to iterate over sendMessage output blocks from a previous step"><figcaption></figcaption></figure>


---

# Agent Instructions: 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:

```
GET https://docs.fastn.ai/flow-setup-essentials/designing-a-flow/loop.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
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.
