---
title: "config.yaml"
manual: "Content Blocks"
version: "2.4"
permalink: "https://docs.typo3.org/permalink/friendsoftypo3/content-blocks:cb-definition-editor-interface@2.4"
source: "Definition/ConfigYaml/Index.rst"
rendered: "2026-09-22T14:38:30+00:00"
---

# config.yaml {#cb-definition-editor-interface}

The heart of a Content Block is the **config.yaml** file. This YAML
file defines both the available fields and the structure:

**EXT:some_extension/ContentBlocks/ContentElements/content-block-name/config.yaml**

```yaml
name: vendor/content-block-name
fields:
  - identifier: header
    useExistingField: true
  - identifier: my_text_field
    type: Text
    max: 10
```

First of all, a `name` has to be defined. It must be unique inside your
installation. It consists, similarly to composer package names, of a vendor and
a package part separated by a slash. It is used to prefix new field names, new
tables and record type identifiers.

Inside `fields` you define the structure and configuration of the
necessary fields. The `identifier` has to be unique per Content Block.

It is possible to reuse existing fields with the flag `useExistingField`.
This allows e.g. to use the same field `header` or `bodytext` across
multiple Content Blocks with different configuration. Be aware that system
fields shouldn't be reused. A list of sane reusable fields can be referenced in
the documentation. Furthermore, own custom fields can be reused as well.

-   Refer to the [YAML reference](https://docs.typo3.org/permalink/friendsoftypo3/content-blocks:yaml-reference@2.4) for a complete overview.
-   Learn more about [reusing fields](https://docs.typo3.org/permalink/friendsoftypo3/content-blocks:cb-reuse-existing-fields@2.4)
-   For more information about the YAML syntax refer to [YAML RFC](https://github.com/yaml/summit.yaml.io/wiki/YAML-RFC-Index)