# Load balancing: Get valid engines

Information note**LOCKED.**   
  
This API is extremely reliable and will not be broken unless absolutely necessary.

## Method

POST

## Path

/qrs/loadbalancing/validengines

## Description

Get the Qlik Sense Engine Services (QESs) that can open an app, identified by `{appID}`, for the Qlik Sense Proxy Service (QPS) identified by `{proxyID}` and `{proxyPrefix}`.

## Body

```
LoadBalancingRequest:
{
   "proxyID": [GUID for a proxy],
   "proxyPrefix": [String that identifies the virtual proxy that is used when making the request],
   "appID": [GUID for an app],
   "loadBalancingPurpose": Production/Development/Any
}
```

## Return value

```
LoadBalancingResult:
{
  "appID": [GUID; the same as in the request],
  "validEngines": [A list of strings, each containing a hostname and port in "hostname:port" format],
  "loadBalancingResultCode": Ok/AppNotFound/ProxyNotFound/ProxyPrefixNotFound
}
```

## Optional parameters

-