# Overview

Get started with API.1 to retrieve Your Customer's data from their Accounting System. This section describes how to call API.1: authentication, request conventions, and how to retrieve data. You'll work with RESTful APIs, JSON responses, and an API Key for authentication.

### RESTful APIs

Our APIs are built using a RESTful architecture.

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### JSON Responses

All our responses are in JSON format.

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### API Key

To access API.1, you'll need to create an API Key in the [Client Portal](https://github.com/Zwapgrid/documentation-external/blob/main/api-1-documentation/get-started/client-portal/api-keys.md).

You must pass your API key in the following HTTP header with every API call:

```
x-api-key: YOUR_API_KEY_HERE
```

{% hint style="info" %}
Remember to replace `YOUR_API_KEY_HERE` with your actual API key.
{% endhint %}

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### Correlation ID

For better traceability and support, you must generate and pass a unique Correlation ID (GUID) with each API request.

For example:

```
x-correlation-id: YOUR_UNIQUE_GUID
```

{% hint style="info" %}
A GUID (Globally Unique Identifier) is a unique reference number used for identification.
{% endhint %}

***

### Polling

You access data from connected accounting systems by polling API.1. You can poll the Consent API for consent status until it is Accepted; then call the Accounting API (for example for invoices or reports) whenever you need data. When calling the Accounting API, you pass the Consent ID in the request path.


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# 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.zwapgrid.com/get-started/get-started.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.