--- title: "System modules" manual: "Getting Started" version: "13.4" permalink: "https://docs.typo3.org/permalink/t3start:system-modules@13.4" source: "Concepts/Backend/SystemModules/Index.rst" rendered: "2026-09-24T15:39:32+00:00" --- # System modules {#system-modules} System modules are backend modules in the group "System" and they are only available to backend users with admin permissions. Some modules are only available when you have an optional system extension installed. If you want to see all available modules you can also make a full TYPO3 install, see [https://get.typo3.org/misc/composer/helper](https://get.typo3.org/misc/composer/helper). **Backend modules in group "System"** - [Permissions](https://docs.typo3.org/permalink/t3start:permissions@13.4) - [Backend Users](https://docs.typo3.org/permalink/t3start:backend-users@13.4) - [Reactions (optional)](https://docs.typo3.org/permalink/t3start:reactions-optional@13.4) - [Webhooks (optional)](https://docs.typo3.org/permalink/t3start:webhooks-optional@13.4) - [Scheduler (optional)](https://docs.typo3.org/permalink/t3start:scheduler-optional@13.4) - [DB check (optional)](https://docs.typo3.org/permalink/t3start:db-check-optional@13.4) - [Configuration](https://docs.typo3.org/permalink/t3start:configuration@13.4) - [Reports (optional)](https://docs.typo3.org/permalink/t3start:reports-optional@13.4) - [Log](https://docs.typo3.org/permalink/t3start:log@13.4) ## Permissions {#system-modules-permissions} In TYPO3, you can grant permissions to backend users. At first, a newly created backend user without any administrative privileges has no access to neither the page module nor the pages in the backend. The module **System > Permissions** can be used to view or edit these backend user permissions for pages in the backend. See also TYPO3 Explained, [Permissions management](https://docs.typo3.org/m/typo3/reference-coreapi/13.4/en-us/Administration/PermissionsManagement/Index.html#permissions-management). ## Backend Users {#system-modules-backend-users} The module **System > Backend Users** is used to create, edit and delete backend users. See also TYPO3 Explained, [Backend user management](https://docs.typo3.org/m/typo3/reference-coreapi/13.4/en-us/Administration/UserManagement/Index.html#user-management). ## Reactions (optional) {#system-modules-reactions} This module is only available if the system extension [`typo3/cms-reactions`](https://packagist.org/packages/typo3/cms-reactions) is installed. This extension handles **incoming** webhooks to TYPO3. It also provides a corresponding backend module to manage reaction records. It has its own manual: [TYPO3 Reactions](https://docs.typo3.org/c/typo3/cms-reactions/13.4/en-us/Index.html#start). ## Webhooks (optional) {#system-modules-webhooks} This module is only available if the system extension [`typo3/cms-webhooks`](https://packagist.org/packages/typo3/cms-webhooks) is installed. This extension handles **outgoing** webhooks to TYPO3. It also provides a corresponding backend module to manage webhook records in TYPO3. Unfortunately this extension is not documented at the time of writing. ## Scheduler (optional) {#system-modules-scheduler} This module is only available if the system extension [`typo3/cms-scheduler`](https://packagist.org/packages/typo3/cms-scheduler) is installed. The Scheduler supports one-time or periodic execution of tasks that can be delivered by any extension. It has its own manual: [TYPO3 Scheduler](https://docs.typo3.org/c/typo3/cms-scheduler/13.4/en-us/Index.html#start). ### Cron jobs in Scheduler {#system-modules-scheduler-cronjobs} The backend module called [TYPO3 Scheduler](https://docs.typo3.org/c/typo3/cms-scheduler/13.4/en-us/Index.html#start) can be used to perform a task that you defined previously in the scheduler. The scheduler can be triggered by a cron job. In your terminal you can type **Create or open the crontab** ```shell crontab -e ``` to create a new job on unix-like operating systems. In [Setting up the cron job](https://docs.typo3.org/c/typo3/cms-scheduler/13.4/en-us/Installation/CronJob/Index.html#cron-job) you can see how this works. Normally you have to define the time or a time interval in which the job should be performed once or frequently. To test your pattern you can insert it [here](https://crontab.guru/) and test if it performs like you expect. When you are not familiar with cron jobs we refer to [https://en.wikipedia.org/wiki/Cron](https://en.wikipedia.org/wiki/Cron). ## DB check (optional) {#system-modules-dbcheck} This module is only available if the system extension [`typo3/cms-lowlevel`](https://packagist.org/packages/typo3/cms-lowlevel) is installed. The *Database (DB) check* module offers functions related to the database and its content. - **Record Statistics** Shows a count of the various records in the database, broken down by type for pages and content elements. - **Relations** Checks if certain relations are empty or broken, typically used to check if files are being referenced. - **Search** A tool to search through the whole database. It offers an advanced mode which is similar to a visual query builder. - **Check and update global reference index** TYPO3 CMS keeps a record of relations between all records. This may get out of sync when certain operations are performed without the strict context of the backend. It is therefore useful to update this index regularly. Some third party extensions offer similar but extended functionality around the database, for example [`fixpunkt/backendtools`](https://packagist.org/packages/fixpunkt/backendtools) can be used during development to find all pages that contain a certain plugin or that use a certain backend layout etc. ## Configuration {#system-modules-configuration} The *Configuration* module can be used to view the various configuration arrays used by the CMS. It is not the goal of this tutorial to describe the role of each of these arrays, you can discover their function as you dig deeper into TYPO3 CMS. Let's just mention that the `$GLOBALS['TYPO3_CONF_VARS']` contains global configuration values. ## Reports (optional) {#system-modules-reports} This module is only available if the system extension [`typo3/cms-reports`](https://packagist.org/packages/typo3/cms-reports) is installed. The **System > Reports** module contains information and diagnostic data about your TYPO3 installation. It is recommended that you regularly check the "Status Report" as it will inform you about configuration errors, security issues, etc. This module has its own dedicated manual: [TYPO3 Reports](https://docs.typo3.org/c/typo3/cms-reports/13.4/en-us/Index.html#start). It can be extended by third-party extensions. For example [`apache-solr-for-typo3/solr`](https://packagist.org/packages/apache-solr-for-typo3/solr) offers its own section in the report module. ## Log {#system-modules-log} The TYPO3 CMS backend logs a number of actions performed by backend users: login, cache clearing, database entries (creation, update, deletion), settings changes, file actions and errors. A number of filters are available to help filter this data.