# How to Enable File Logging for an SSO Application in io.Connect Desktop 9.0

**URL:** <https://community.interop.io/t/how-to-enable-file-logging-for-an-sso-application-in-io-connect-desktop-9-0/594>\
**Category:** io.Connect Desktop\
**Tags:** FAQs\
**Created:** [June 5, 2026, 8:09am UTC](https://community.interop.io/t/how-to-enable-file-logging-for-an-sso-application-in-io-connect-desktop-9-0/594 "2026-06-05T08:09:57Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![toni.petrov](https://yyz2.discourse-cdn.com/flex028/user_avatar/community.interop.io/toni.petrov/32/17_2.png) [@toni.petrov](https://community.interop.io/u/toni.petrov)\
**Post date:** [June 5, 2026, 8:09am UTC](https://community.interop.io/t/how-to-enable-file-logging-for-an-sso-application-in-io-connect-desktop-9-0/594/1 "2026-06-05T08:09:57Z")

</div>

**Applies to:** io.Connect Desktop (9.x version stream)

## Problem

When using an SSO application in io.Connect Desktop, logs from `window.io.logger` appear in the browser console but are not written to any log files (e.g., `application.log` or a dedicated SSO application log file). The Logger API initializes successfully, sub-loggers are created correctly, and log messages appear in the browser console with proper formatting, but no entries are persisted to disk.

## Solution

### Step 1: Enable Logging in the App Definition

Add `"allowLogging": true` to the top level of your SSO application definition JSON file:

```auto
{
  "name": "sso-application",
  "title": "My SSO Login",
  "type": "window",
  "allowLogging": true,
  "details": {
    "url": "http://localhost:3000",
    "mode": "tab",
    "autoInjectAPI": {
      "enabled": true,
      "autoInit": true
    }
  }
}

```

### Step 2: Add the `"out"` Appender to `logger.json`

Ensure your `logger.json` file (located in `<installation_location>/interop.io/io.Connect Desktop/Desktop/config`) includes the `"out"` appender of type `"stdout"` under the `"appenders"` section.

```auto
"out": {
  "type": "stdout"
}

```

### Step 3: Verify the Publish Level

The Logger API has a `publishLevel()` method that controls which log entries are written to the file. If the publish level is set too high (e.g., `"warn"`), lower-level messages like `"info"` or `"debug"` will not appear in the log files. You can check or set it via the Logger API — see the [Logger API – JavaScript](https://docs.interop.io/desktop/capabilities/logging/javascript/index.html) documentation for details.

## Note for io.Connect Desktop 10.0 and Later

Starting with io.Connect Desktop 10.0, the logging configuration has moved from the standalone `logger.json` file to the `"logging"` \> `"configuration"` property in the `system.json` system configuration file. The `logger.json` approach described above applies to the 9.0 version stream. If you are running io.Connect Desktop 10.0 or later, configure your custom appenders and categories under the `"logging"` key in `system.json` instead. The Gilding Configuration (`gilding.json`) is also relevant only for the 9.0 version stream.

## Related Documentation

- [Logging Overview](https://docs.interop.io/desktop/capabilities/logging/overview/index.html)
- [Logger API – JavaScript](https://docs.interop.io/desktop/capabilities/logging/javascript/index.html)
- [System Configuration – Logging](https://docs.interop.io/desktop/developers/configuration/system/index.html#logging)
- [Application Configuration – Logging](https://docs.interop.io/desktop/developers/configuration/application/index.html#logging)