# Custom Fields Prepare Field

<!-- meta: type=event-onCustomFieldsPrepareField; location=Joomla Events › Custom Fields Events; category=Trigger; platforms=Joomla -->

## Overview

When it runs: When a custom field value is prepared for display on the site or in output.

Plugins format field output per context (article, user, contact, etc.).

Each run also includes who was logged in at the time and what kind of item was involved — see audit_user and audit_type in Payload Fields below.

This trigger is not connected yet — flows using it will not run until JOrchestrator adds support for this Joomla hook.

When this trigger fires, JOrchestrator starts the flow and passes the incoming event or request data to the next connected step. Configure filtering, payload shape, and security on the **Design** tab.

## Why use this node

Custom Fields Prepare Field is a **trigger** in the **Joomla Events › Custom Fields Events** group. Triggers start a flow. They listen for an external signal — a CMS event, inbound HTTP call, payment notification, or schedule — and pass the incoming data to the first downstream step.

Typical reasons teams add **Custom Fields Prepare Field** to a flow:

- Automate backend work when Joomla fires `CustomFieldsPrepareField`
- Notify administrators or sync external systems on this CMS lifecycle event
- Enrich or validate CMS data before it is persisted
- Audit user, content, or extension activity without custom plugins

## When it runs

When a custom field value is prepared for display on the site or in output.

## Example workflows

Common patterns on the canvas:

1. **Custom Fields Prepare Field** → **Send Notification** (admin alert)
2. **Custom Fields Prepare Field** → **Insert Row** (audit log)
3. **Custom Fields Prepare Field** → **If** → **Send Email** / **Update Article**

## Properties panel

The designer shows these tabs for this node:

| Tab | Purpose |
|-----|---------|
| **Info** | Plain-language description and output payload fields for downstream steps |
| **Design** | Trigger configuration and payload schema |

### System (automatic — not edited by the user)

These fields are managed by the designer or runtime — you do not type into them directly:

| Property key | Label | Type | Required | Visible when | Notes |
|--------------|-------|------|----------|--------------|-------|
| `_nodeId` | Node ID | `node-id` | No | — | — |

### User-configured — General tab

| Property key | Label | Type | Required | Visible when | Notes |
|--------------|-------|------|----------|--------------|-------|
| `label` | Label | `text` | No | — | Node label |

### CMS site configuration (not on this node's properties panel)

Credentials, API keys, mailers, SMTP, and integration defaults are configured in the CMS plugin under **Node Configuration**, not per step on this node. Link the flow to a domain before testing CMS-backed fields.

## Output payload fields

After this step runs, later nodes can reference these fields using placeholders such as
`{{custom_fields_prepare_field.context}}`.

| Field key | Type | Description |
|-----------|------|-------------|
| `context` | string | Joomla event context string. |
| `subject.name` | string | Nested field "subject.name" from this node's output payload. |
| `subject.type` | string | Nested field "subject.type" from this node's output payload. |
| `subject.value` | string | Nested field "subject.value" from this node's output payload. |
| `form` | object | Nested object from this node's output. |
| `audit_user.id` | number | Nested field "audit_user.id" from this node's output payload. |
| `audit_user.username` | string | Nested field "audit_user.username" from this node's output payload. |
| `audit_user.email` | string | Nested field "audit_user.email" from this node's output payload. |
| `audit_user.name` | string | Nested field "audit_user.name" from this node's output payload. |
| `audit_user.guest` | boolean | Nested field "audit_user.guest" from this node's output payload. |
| `audit_user.client` | string | Nested field "audit_user.client" from this node's output payload. |
| `audit_type` | string | What kind of item triggered the event — for example article, category, or user. |

## Related nodes

Other steps in the same area of the palette:

- **Custom Fields After Save** (`event-onCustomFieldsAfterSave`) — Joomla Events › Custom Fields Events
- **Custom Fields Before Save** (`event-onCustomFieldsBeforeSave`) — Joomla Events › Custom Fields Events
- **Custom Fields Prepare DOM** (`event-onCustomFieldsPrepareDom`) — Joomla Events › Custom Fields Events