> For the complete documentation index, see [llms.txt](https://developer.vario-software.de/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developer.vario-software.de/documentation/readme.md).

# Overview

This section contains the technical documentation for extending and integrating **VARIO Cloud** — a cloud ERP system you can extend in three ways:

| Approach      | You build                                                               | Runs                    | Start here                                                         |
| ------------- | ----------------------------------------------------------------------- | ----------------------- | ------------------------------------------------------------------ |
| **REST API**  | An integration in any language that reads and writes ERP data over HTTP | Anywhere                | [REST API Introduction](/documentation/rest-api/introduction.md)   |
| **Apps**      | A self-hosted web app embedded into the ERP UI, talking to the REST API | Your own infrastructure | [Apps Introduction](/documentation/apps/introduction.md)           |
| **Scripting** | Server-side JavaScript running inside the ERP itself                    | VARIO backend           | [Scripting Introduction](/documentation/scripting/introduction.md) |

Most integrations combine them: an App for the UI and configuration, the REST API for data, Scripting for in-ERP automation, and [Webhooks](/documentation/webhooks/introduction.md) to react to changes.

## Find your way

**I want to call the API.**\
Get a token via [Authentication](/documentation/rest-api/authentication.md), then send requests to your tenant base URL — see [REST API Introduction](/documentation/rest-api/introduction.md). Mind the [rate limits](/documentation/rest-api/rate-limiting.md), and query data with [VQL](/documentation/fundamentals/vql.md).

**I want to build an App.**\
Read the [Apps Introduction](/documentation/apps/introduction.md), then [Create an App](/documentation/apps/create-an-app.md) to get credentials, and follow the [Quickstart](/documentation/apps/quickstart.md). The [App Manifest](/documentation/apps/app-manifest.md) reference describes every field.

**I want to react to changes in the ERP.**\
Register a webhook — see [Webhooks Introduction](/documentation/webhooks/introduction.md).

**I want to automate business logic inside the ERP.**\
No external server needed: use [Workflows](/documentation/scripting/workflows.md) or [Batch Processing](/documentation/scripting/batch-processing.md), with the [service layer](/documentation/scripting/services.md) and reusable [Script Modules](/documentation/scripting/script-modules.md).

**I want to store my own data on ERP records.**\
Use [Custom Fields](/documentation/fundamentals/custom-fields.md) to extend articles, accounts, documents and more.

**I'm building a shop, shipping, banking, accounting or POS integration.**\
These verticals follow established platform patterns. See [App Backends](/documentation/apps/app-backends.md) for a one-page guide per domain.

**Something isn't working as expected.**\
Check the FAQ — it collects the mistakes developers hit most often.

## How this documentation is organised

| Section                                                     | Content                                            |
| ----------------------------------------------------------- | -------------------------------------------------- |
| [REST API](/documentation/rest-api/introduction.md)         | Base URL, authentication, rate limiting            |
| [Webhooks](/documentation/webhooks/introduction.md)         | Reacting to ERP events, registration, delivery     |
| [Apps](/documentation/apps/introduction.md)                 | App model, credentials, manifest, quickstart       |
| [Fundamentals](/documentation/fundamentals/introduction.md) | Concepts that apply everywhere: custom fields, VQL |
| [Scripting](/documentation/scripting/introduction.md)       | Server-side JavaScript in the ERP                  |
| FAQ                                                         | Common pitfalls and their answers                  |

Beyond this space you'll also find the **API Reference** (every endpoint) and the **Scripting Reference** (every service and type).

{% hint style="info" %}
New to the platform? Start with the Introduction of the section you need. Looking for a specific detail? Jump straight to the relevant page — every page is written to stand on its own.
{% endhint %}


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