# Introduction

Code metrics are used in:

* Rules to raise issues, for example, when a certain level of complexity is reached for a function in the code. See [overview](https://docs.sonarsource.com/sonarqube-server/2025.2/user-guide/rules/overview "mention") for more information.
* Quality gate definition, for example, you can set a condition on the total number of raised issues in the code. See [introduction-to-quality-gates](https://docs.sonarsource.com/sonarqube-server/2025.2/quality-standards-administration/managing-quality-gates/introduction-to-quality-gates "mention") for more information.
* The mode of your SonarQube Server instance, either [mqr-mode](https://docs.sonarsource.com/sonarqube-server/2025.2/instance-administration/analysis-functions/instance-mode/mqr-mode "mention") or [standard-experience](https://docs.sonarsource.com/sonarqube-server/2025.2/instance-administration/analysis-functions/instance-mode/standard-experience "mention"), will determine which code metrics you see in the UI.

You can use different tools in the SonarQube Server to monitor and compare your project or portfolio’s code metrics.

{% hint style="info" %}
If you’re using an external monitoring system, you can retrieve the metric values through the [web-api](https://docs.sonarsource.com/sonarqube-server/2025.2/extension-guide/web-api "mention").
{% endhint %}

## Related pages <a href="#related-pages" id="related-pages"></a>

* [metrics-definition](https://docs.sonarsource.com/sonarqube-server/2025.2/user-guide/code-metrics/metrics-definition "mention")
* [monitoring-project-metrics](https://docs.sonarsource.com/sonarqube-server/2025.2/user-guide/code-metrics/monitoring-project-metrics "mention")
* [monitoring-portfolio-metrics](https://docs.sonarsource.com/sonarqube-server/2025.2/user-guide/code-metrics/monitoring-portfolio-metrics "mention")
* [metrics-parameters](https://docs.sonarsource.com/sonarqube-server/2025.2/instance-administration/analysis-functions/metrics-parameters "mention")