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

# Introduction

NexumAPI can be used in lieu of any SymXchange request. We offer a completely [JSON](https://en.wikipedia.org/wiki/JSON)-encoded alternative to [SOAP](https://en.wikipedia.org/wiki/SOAP), as well as access to a growing list of additional features.

### Resources

* Obtaining an [API key](/nexum/authentication.md)
* Sending [nil fields](/nexum/resources/nil-field-support.md) in a request
* Read the [SymXchange API reference](/nexum/symxchange/api-reference.md)
* Contact us at <development@libum.io>
* Learn about our [privacy policy](https://libum.io/legal/privacy/)

{% hint style="success" %}
At [Libum](https://libum.io/), we understand what it's like building full-stack apps that integrate with the Symitar core. If there's a way we can improve the feature set of NexumAPI, please let us know at <development@libum.io> or through our [Feedback](https://feedback.libum.io) portal.
{% endhint %}

## Key concepts

### SymXchange

SymXchange is an API that leverages web services that provide third-party vendors, credit unions, and JHA products the ability to access the system database. With SymXchange, you can use third-party vendor applications to perform transactions, inquiries, file maintenance, and run PowerOn specfiles on member accounts.

SymXchange uses [XML](https://en.wikipedia.org/wiki/XML) and [Web Services Description Language (WSDL)](https://en.wikipedia.org/wiki/Web_Services_Description_Language) files with SOAP specifications to implement web services over client and third-party system network .

### NexumAPI attributes

NexumAPI attributes are a mechanism for users to optionally include in each request payload to gain access to custom features of SymXchange only available through NexumAPI. As an example, we offer an attribute called <mark style="color:purple;">`customFields`</mark> which enables the user to include metadata they wish to bubble up to their logging transports.

#### Example of customFields

In this example, the <mark style="color:purple;">`appId`</mark> field will be included in the logs to reflect which application the request originated from.

```json
// ...
"nxAttributes": {
  "customFields": {
    "appId": "glaci"
  }
},
// ...
```

## Guides

Jump into one of our guides to learn more.

{% content-ref url="/pages/5pj4yfXPg38Hh9rfpRQj" %}
[Quickstart](/nexum/quickstart.md)
{% endcontent-ref %}

{% content-ref url="/pages/YdrDD6SKfo3H96iZfopE" %}
[MCP Quickstart](/nexum/mcp-quickstart.md)
{% endcontent-ref %}


---

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