---
title: "Fields Overview — Config, Validation, Virtual, Admin Options"
aliases: [payload-fields-overview, payload-field-config]
tags: [payloadcms, fields, validation, virtual-fields, admin-panel]
sources: [raw/fields__overview.md]
created: 2026-05-15
updated: 2026-05-15
---

# Fields Overview — Config, Validation, Virtual, Admin Options

Fields are the building blocks of Payload. They define the DB schema **and** auto-generate Admin Panel UI. This article covers shared config capabilities that apply across all field types: virtual fields, validation, default values, admin options, and custom components.

See [[wiki/payloadcms/fields-basic|Fields: Basic]] for scalar field types and [[wiki/payloadcms/fields-complex|Fields: Complex]] for structural/relational types.

---

## Field Categories

| Category | Purpose | `name` required? |
|----------|---------|-----------------|
| **Data** | Stored in DB | Yes |
| **Presentational** | Layout only (Row, Collapsible, unnamed Tabs/Group, UI) | No |
| **Virtual** | Computed/derived, not stored | Yes |

### Data Fields (full list)

Array, Blocks, Checkbox, Code, Date, Email, Group (named), JSON, Number, Point, Radio, Relationship, Rich Text, Select, Tabs (named), Text, Textarea, Upload

### Presentational Fields

Collapsible, Row, Tabs (unnamed), Group (unnamed), UI

### Virtual Fields

- **Join** — purpose-built virtual type for bi-directional relationships
- **Any field** with `virtual: true` or `virtual: 'path.to.value'`

---

## Virtual Field Configuration

Any data field type can be made virtual by adding the `virtual` property.

### Boolean virtual — computed via hook

```ts
{
  name: 'fullName',
  type: 'text',
  virtual: true,
  hooks: {
    afterRead: [({ siblingData }) =>
      `${siblingData.firstName} ${siblingData.lastName}`
    ]
  }
}
```

### String path virtual — resolves relationship data

```ts
{
  name: 'authorName',
  type: 'text',
  virtual: 'author.name'  // author relationship must exist on the same collection
}
```

**Path syntax rules:**
- Dot notation traverses relationships: `author.profile.bio`
- `hasMany` relationships return arrays: `categories.title` → `['Tech', 'News']`
- Source relationship field **must** exist in the same schema
- Resolved at query time, not stored

**Use cases:** display relationship names without ID, computed word counts, formatted summaries.

```json
// API response includes virtual fields alongside real ones
{
  "id": "123",
  "title": "My Post",
  "author": "64f123...",
  "authorName": "John Doe",
  "categoryTitles": ["Tech", "News"],
  "wordCount": 450
}
```

---

## Field Names

- Must be **unique** among siblings
- Follow JavaScript identifier conventions: start with letter or `_`, only letters/numbers/`_`
- **Avoid** hyphens (breaks GraphQL enum generation) and leading digits
- **Reserved names** (cannot be used): `__v`, `salt`, `hash`, `file`, `status` (with Postgres + drafts)

---

## Default Values

```ts
// Static
{ name: 'status', type: 'text', defaultValue: 'draft' }

// Dynamic function — runs on create/update
{
  name: 'attribution',
  type: 'text',
  defaultValue: ({ user, locale, req }) =>
    `${translation[locale]} ${user.name}`
}
```

Dynamic `defaultValue` receives: `user`, `locale`, `req` (use `req.payload` for Local API calls). Can be `async`.

---

## Validation

Fields auto-validate based on type and options (`required`, `min`, `max`). Override with `validate`:

```ts
{
  name: 'myField',
  type: 'text',
  validate: (value, { user, data, siblingData, operation, id, req, event }) =>
    Boolean(value) || 'This field is required'
}
```

Returns `true` (valid) or an error string.

### Validation Context (`ctx`)

| Property | Description |
|----------|-------------|
| `data` | Full document being edited |
| `siblingData` | Fields in same parent |
| `operation` | `'create'` or `'update'` |
| `path` | Array path: `['group', 'myArray', '1', 'field']` |
| `id` | Document ID (undefined during create) |
| `req` | HTTP request with `payload`, `user`, etc. |
| `event` | `'onChange'` or `'submit'` |

### Localized error messages

```ts
validate: (value, { req: { t } }) =>
  Boolean(value) || t('validation:required')
```

### Reuse built-in validators

```ts
import { text } from 'payload/shared'

validate: (val, args) => {
  if (val === 'bad') return 'Cannot be "bad"'
  return text(val, args)  // delegate to built-in
}
```

Available: `array, blocks, checkbox, code, date, email, json, number, point, radio, relationship, richText, select, tabs, text, textarea, upload`

### Validation performance

Admin Panel validates on **every change**. For expensive ops (DB queries), gate on `event`:

```ts
validate: async (val, { event }) => {
  if (event === 'onChange') return true
  const response = await fetch(`/api/check?val=${val}`)
  return response.ok || 'Invalid value'
}
```

---

## Field-level Hooks

```ts
{
  name: 'myField',
  type: 'text',
  hooks: {
    beforeValidate: [...],
    beforeChange: [...],
    afterChange: [...],
    afterRead: [...]
  }
}
```

See [[wiki/payloadcms/hooks|Hooks]] for full details.

---

## Field-level Access Control

```ts
{
  name: 'sensitiveData',
  type: 'text',
  access: {
    read: ({ req: { user } }) => Boolean(user?.isAdmin),
    create: () => false,
    update: ({ req: { user } }) => Boolean(user?.isAdmin),
  }
}
```

See [[wiki/payloadcms/access-control|Access Control]] for full details.

---

## Custom ID Fields

Override auto-generated ID:

```ts
fields: [
  {
    name: 'id',
    type: 'number',  // or 'text'
    required: true,
  }
]
```

- Only `number` or `text` types allowed
- Text IDs must not contain `/` or `.` characters

---

## Admin Options

Configured via `admin: {}` on any field:

| Option | Description |
|--------|-------------|
| `condition` | `(data, siblingData, ctx) => boolean` — show/hide field |
| `components` | Swap individual UI parts (see Custom Components below) |
| `description` | Help text (string, function, or React component) |
| `position` | `'sidebar'` or `'main'` (default) |
| `width` | CSS width — useful in `row` fields |
| `style` | Inline CSS on root element |
| `className` | CSS class on root element |
| `readOnly` | UI-only; no effect on API |
| `disabled` | Hide from all admin surfaces (`true`) or specific ones (object) |
| `hidden` | Converts to `<input type="hidden">` — still submits |

### `admin.disabled` granular control

```ts
admin: { disabled: { column: true, filter: true } }
// Keys: field, column, filter, groupBy, bulkEdit
```

UI fields default to `disabled: { bulkEdit: true }`.

### Conditional Logic

```ts
{
  name: 'greeting',
  type: 'text',
  admin: {
    condition: (data, siblingData, { blockData, path, user }) => {
      return Boolean(data.enableGreeting)
    }
  }
}
```

---

## Custom Components

Swap any part of a field's UI via `admin.components`:

| Component | Renders in | Notes |
|-----------|-----------|-------|
| `Field` | Edit View — the input | Use `useField()` hook to manage value |
| `Cell` | List View — table cell | Use `DefaultCellComponentProps` / `DefaultServerCellComponentProps` |
| `Filter` | List View — filter dropdown | Receives `disabled, onChange, operator, value` |
| `Label` | Anywhere labels appear | |
| `Error` | Below input on validation fail | |
| `Description` | Below label | Use component for dynamic/reactive help text |
| `Diff` | Version Diff View | Only visible when versioning is enabled |
| `beforeInput` | Before `<input>` element | Array of components |
| `afterInput` | After `<input>` element | Array of components |

### Field component — managing value

```tsx
'use client'
import { useField } from '@payloadcms/ui'

export const CustomTextField = () => {
  const { value, setValue } = useField()
  return <input onChange={(e) => setValue(e.target.value)} value={value} />
}
```

### TypeScript for custom components

```ts
import type {
  TextFieldClientComponent,
  TextFieldServerComponent,
  TextFieldLabelClientComponent,
  TextFieldDescriptionClientComponent,
  TextFieldErrorClientComponent,
  TextFieldDiffClientComponent,
} from 'payload'
```

Convention: `{FieldType}{ComponentRole}{ServerOrClient}Component` (e.g. `TextFieldLabelClientComponent`)

### Cell component example

```tsx
'use client'
import type { DefaultCellComponentProps } from 'payload'

export const PriceCellComponent: React.FC<DefaultCellComponentProps> = ({ cellData, rowData }) => {
  const currency = rowData.currency || 'USD'
  return <span>{new Intl.NumberFormat('en-US', { style: 'currency', currency }).format(cellData)}</span>
}
```

---

## Key Takeaways

- **Three categories**: Data (stored), Presentational (layout), Virtual (computed/derived)
- **Any field can be virtual** with `virtual: true` (hook-computed) or `virtual: 'path.string'` (relationship path)
- **Virtual path fields** auto-resolve relationship data without a DB column; `hasMany` → returns arrays
- **Reserved field names** (`__v`, `salt`, `hash`, `file`, `status` with Postgres+drafts) cause silent config sanitization
- **Validation** runs on every keystroke in Admin — use `event === 'onChange'` guard for expensive async checks
- **`validate` returns** `true` (valid) or an error message string
- **`defaultValue`** can be async; receives `{ user, locale, req }` — use `req.payload` for Local API
- **`admin.disabled`** accepts boolean or object with keys `{ field, column, filter, groupBy, bulkEdit }`
- **Custom components** registered via path strings in `admin.components`; use `useField()` to wire value
- **TypeScript types** follow `{FieldType}{Role}{Env}Component` naming convention

---

## Sources

- `raw/fields__overview.md` — https://payloadcms.com/docs/fields/overview
