---
title: "Overriding Third-Party Resource Configs"
manual: "TCA_API"
version: "2.2"
permalink: "https://docs.typo3.org/permalink/maikschneider/tca-api:configuration-overrides@2.2"
source: "Configuration/Overrides.rst"
rendered: "2026-10-12T13:17:40+00:00"
---

# Overriding Third-Party Resource Configs {#configuration-overrides}

TCA_API mirrors TYPO3's `$GLOBALS['TCA']` \+ `TCA/Overrides/` loading
pattern. Any active extension can modify a resource configuration that was
defined by another extension.

## How it works {#how-it-works}

At boot time the loader runs two passes over every active package:

1.  **Base pass** — loads every `Configuration/TcaApi/*.php` file
    and writes the result into `$GLOBALS['TCA_API']` keyed by
    `resourceName`. When two packages define the same `resourceName`, the
    last package to load wins (TYPO3 package load order).
1.  **Override pass** — requires every `Configuration/TcaApi/Overrides/*.php`
    file (depth 0, sorted alphabetically within each package). Override files
    are plain PHP side-effects on `$GLOBALS['TCA_API']` — no return value is
    expected.

After both passes the global is parsed into typed `ApiDefinition` DTOs and
cached. At runtime, use `ApiRegistry::get()` to read definitions; the
global itself is not guaranteed to be set on cache hits.

## Writing an override file {#writing-an-override-file}

Create a PHP file under `Configuration/TcaApi/Overrides/` in any active
extension. The filename is arbitrary.

**Add a column**

```php
<?php

declare(strict_types=1);

// EXT:my_ext/Configuration/TcaApi/Overrides/ExtendArticles.php
$GLOBALS['TCA_API']['articles']['columns']['subtitle'] = [
    'groups' => ['list', 'show'],
];
```

**Remove a column**

```php
unset($GLOBALS['TCA_API']['articles']['columns']['internal_notes']);
```

**Restrict operations**

```php
$GLOBALS['TCA_API']['articles']['general']['operations'] = ['list', 'show'];
```

**Change a security role**

```php
use MaikSchneider\TcaApi\Enum\AccessRole;

$GLOBALS['TCA_API']['articles']['security']['delete'] = AccessRole::FE_USER;
```

**Add a filter**

```php
use MaikSchneider\TcaApi\Filter\ExactFilter;

$GLOBALS['TCA_API']['articles']['filters']['category_id'] = ExactFilter::class;
```

Multiple overrides for the same resource are applied in alphabetical filename
order within a package, and in TYPO3 package load order across packages. The
last write always wins.

## Explicit vs. implicit mode {#explicit-vs-implicit-mode}

The visibility mode — **implicit** (all TCA columns exposed) vs. **explicit**
(only columns with `groups`) — is re-evaluated after all overrides are
applied.

-   Adding a column with a `groups` key to an otherwise implicit resource
    switches it to explicit mode for that resource.
-   Removing the only column that had `groups` switches it back to implicit.
-   Adding a column *without* `groups` to an explicit resource keeps it
    explicit; the new column is recorded in the DTO but excluded from all
    operation outputs.