# Custom fields

Custom fields extend Strapi’s capabilities by adding new types of fields to content-types and components. Once created or installed, custom fields can be used in the Content-Type Builder and Content Manager just like built-in fields.

The present documentation is intended for custom field creators: it describes which APIs and functions developers must use to create a new custom field. The user guide describes how to install and use custom fields from Strapi's admin panel.

It is recommended that you develop a dedicated plugin for custom fields. Custom-field plugins include both a server and admin panel part. The custom field must be registered in both parts before it is usable in Strapi's admin panel.

Once created and used, custom fields are defined like any other attribute in the model's schema. An attribute using a custom field will have its type represented as customField (i.e. type: 'customField'). Depending on the custom field being used a few additional properties may be present in the attribute's definition (see models documentation).

✏️ NOTES

  • Though the recommended way to add a custom field is through creating a plugin, app-specific custom fields can also be registered within the global register function found in src/index.js and src/admin/app/js files.
  • Custom fields can only be shared using plugins.

# Registering a custom field on the server

PREREQUISITES

Registering a custom field through a plugin requires creating and enabling a plugin (see Plugins development).

Strapi's server needs to be aware of all the custom fields to ensure that an attribute using a custom field is valid.

The strapi.customFields object exposes a register() method on the Strapi instance. This method is used to register custom fields on the server during the plugin's server register lifecycle.

strapi.customFields.register() registers one or several custom field(s) on the server by passing an object (or an array of objects) with the following parameters:

Parameter Description Type
name The name of the custom field String
plugin

(optional)		 The name of the plugin creating the custom fields String
type The data type the custom field will use String

✏️ NOTE

Currently, custom fields cannot add new data types to Strapi and must use existing, built-in Strapi data types described in the models' attributes documentation. Special data types unique to Strapi, such as relation, media, component, or dynamic zone data types, cannot be used in custom fields.

Example: Registering an example "color" custom field on the server:

In the following example, the color-picker plugin was created using the CLI generator (see plugins development):

// path: ./src/plugins/color-picker/server/register.js

'use strict';

module.exports = ({ strapi }) => {
  strapi.customFields.register({
    name: 'color',
    plugin: 'color-picker',
    type: 'string',
  });
};
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The custom field could also be declared directly within the strapi-server.js file if you didn't have the plugin code scaffolded by the CLI generator:

// path: ./src/plugins/color-picker/strapi-server.js

module.exports = {
  register({ strapi }) {
    strapi.customFields.register({
      name: 'color',
      plugin: 'color-picker',
      type: 'text',
    });
  },
};
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# Registering a custom field in the admin panel

PREREQUISITES

Registering a custom field through a plugin requires creating and enabling a plugin (see Plugins development).

Custom fields must be registered in Strapi's admin panel to be available in the Content-type Builder and the Content Manager.

The app.customFields object exposes a register() method on the StrapiApp instance. This method is used to register custom fields in the admin panel during the plugin's admin register lifecycle.

app.customFields.register() registers one or several custom field(s) in the admin panel by passing an object (or an array of objects) with the following parameters:

Parameter Description Type
name Name of the custom field String
pluginId

(optional)		 Name of the plugin creating the custom field String
type Existing Strapi data type the custom field will use

❗️ Relations, media, components, or dynamic zones cannot be used.		 String
icon

(optional)		 Icon for the custom field React.ComponentType
intlLabel Translation for the name IntlObject (opens new window)
intlDescription Translation for the description IntlObject (opens new window)
components Components needed to display the custom field in the Content Manager (see components)
options

(optional)		 Options to be used by the Content-type Builder (see options) Object
Example: Registering an example "color" custom field in the admin panel:

In the following example, the color-picker plugin was created using the CLI generator (see plugins development):

// path: ./src/plugins/color-picker/admin/src/index.js

import ColorPickerIcon from './components/ColorPicker/ColorPickerIcon';

export default {
  register(app) {
    // ... app.addMenuLink() goes here
    // ... app.registerPlugin() goes here

    app.customFields.register({
      name: "color",
      pluginId: "color-picker", // the custom field is created by a color-picker plugin
      type: "string", // the color will be stored as a string
      intlLabel: {
        id: "color-picker.color.label",
        defaultMessage: "Color",
      },
      intlDescription: {
        id: "color-picker.color.description",
        defaultMessage: "Select any color",
      },
      icon: ColorPickerIcon, // don't forget to create/import your icon component 
      components: {
        Input: async () => import(/* webpackChunkName: "input-component" */ "./admin/src/components/Input"),
      },
      options: {
        // declare options here
      },
    });
  } 

  // ... bootstrap() goes here
};
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# Components

app.customFields.register() must pass a components object with an Input React component to use in the Content Manager's edit view.

Example: Registering an Input component

In the following example, the color-picker plugin was created using the CLI generator (see plugins development):

// path: ./src/plugins/color-picker/admin/src/index.js

export default {
  register(app) {
    app.customFields.register({
      // …
      components: {
        Input: async () => import(/* webpackChunkName: "input-component" */ "./Input"),
      } 
      // …
    });
  }
}
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💡 TIP

The Input React component receives several props. The ColorPickerInput file (opens new window) in the Strapi codebase gives you an example of how they can be used.

# Options

app.customFields.register() can pass an additional options object with the following parameters:

Options parameter Description Type
base Settings available in the Base settings tab of the field in the Content-type Builder Object or Array of Objects
advanced Settings available in the Advanced settings tab of the field in the Content-type Builder Object or Array of Objects
validator Validator function returning an object, used to sanitize input. Uses a yup schema object (opens new window). Function

Both base and advanced settings accept an object or an array of objects, each object being a settings section. Each settings section could include:

Each object in the items array can contain the following parameters:

Items parameter Description Type
name Label of the input.
Must use the options.settingName format.		 String
description Description of the input to use in the Content-type Builder String
intlLabel Translation for the label of the input IntlObject (opens new window)
type Type of the input (e.g., select, checkbox) String
Example: Declaring options for an example "color" custom field:

In the following example, the color-picker plugin was created using the CLI generator (see plugins development):

// path: ./src/plugins/color-picker/admin/src/index.js

// imports go here (ColorPickerIcon, pluginId, yup package…)

export default {
  register(app) {
    // ... app.addMenuLink() goes here
    // ... app.registerPlugin() goes here
    app.customFields.register({
    // …
      options: {
        base: [
          /*
            Declare settings to be added to the "Base settings" section
            of the field in the Content-Type Builder
          */
          {
            sectionTitle: { // Add a "Format" settings section
              id: 'color-picker.color.section.format',
              defaultMessage: 'Format',
            },
            items: [ // Add settings items to the section
              {
                /*
                  Add a "Color format" dropdown
                  to choose between 2 different format options
                  for the color value: hexadecimal or RGBA
                */
                intlLabel: {
                  id: 'color-picker.color.format.label',
                  defaultMessage: 'Color format',
                },
                name: 'options.format',
                type: 'select',
                value: 'hex', // option selected by default
                options: [ // List all available "Color format" options
                  {
                    key: 'hex',
                    value: 'hex',
                    metadatas: {
                      intlLabel: {
                        id: 'color-picker.color.format.hex',
                        defaultMessage: 'Hexadecimal',
                      },
                    },
                  },
                  {
                    key: 'rgba',
                    value: 'rgba',
                    metadatas: {
                      intlLabel: {
                        id: 'color-picker.color.format.rgba',
                        defaultMessage: 'RGBA',
                      },
                    },
                  },
                ],
              },
            ],
          },
        ],
        advanced: [
          /*
            Declare settings to be added to the "Advanced settings" section
            of the field in the Content-Type Builder
          */
        ],
        validator: args => ({
          format: yup.string().required({
            id: 'options.color-picker.format.error',
            defaultMessage: 'The color format is required',
          }),
        })
      },
    });
  }
}
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💡 TIP

The Strapi codebase gives an example of how settings objects can be described: check the baseForm.js (opens new window) file for the base settings and the advancedForm.js (opens new window) file for the advanced settings. The base form lists the settings items inline but the advanced form gets the items from an attributeOptions.js (opens new window) file.

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