---
title: "Developer"
manual: "Headless"
version: "main"
permalink: "https://docs.typo3.org/permalink/friendsoftypo3/headless:developer@main"
source: "Developer/Index.rst"
rendered: "2026-10-14T09:29:03+00:00"
---

# Developer {#developer}

How to shape and extend the JSON output. Each topic has its own page:

-   [cObjects](https://docs.typo3.org/permalink/friendsoftypo3/headless:developer-cobjects@main) — the headless TypoScript
    content objects: `JSON`, `CONTENT_JSON`, plus the casting objects
    `BOOL`/`INT`/`FLOAT`.
-   [Custom content](https://docs.typo3.org/permalink/friendsoftypo3/headless:developer-custom-content@main) — custom content
    elements, internal Extbase plugins, integrating external plugins
    (EXT:news et al.), custom TypoScript objects and meta-data overrides.
-   [Data processors](https://docs.typo3.org/permalink/friendsoftypo3/headless:dataprocessors@main) — `DatabaseQueryProcessor`,
    `FilesProcessor`, `MenuProcessor`, `GalleryProcessor` and friends,
    with their headless-specific options.
-   [Events](https://docs.typo3.org/permalink/friendsoftypo3/headless:developer-events@main) — PSR-14 extension points and how to
    register listeners; full list in [Reference: Events](https://docs.typo3.org/permalink/friendsoftypo3/headless:ref-events@main).
-   [Images & files](https://docs.typo3.org/permalink/friendsoftypo3/headless:images@main) — file/image payloads and processing
    configuration (the storage proxy itself is a feature flag, see
    [Configuration](https://docs.typo3.org/permalink/friendsoftypo3/headless:configuration@main)).
-   [Snippets](https://docs.typo3.org/permalink/friendsoftypo3/headless:developer-snippets@main) — drop-in recipes for common tasks.

Form output decorators are documented with the rest of the form
integration in [EXT:form](https://docs.typo3.org/permalink/friendsoftypo3/headless:integrations-form@main); the default response shape and
every shipped `lib.*` object in [Reference: TypoScript helpers](https://docs.typo3.org/permalink/friendsoftypo3/headless:ref-typoscript@main).