Actor input schema

Documentation of Apify actors - defining your actor's input schema.

Specification version 1

Actor input schema defines the input that the actor accepts and the UI components used for input at the Apify platform. Using input schema, you can provide UI to actor users that is easy to use, and also ensure that the input of your actor is valid.

Input schema must be stored in a file named INPUT_SCHEMA.json in the root directory of the actor. Maximum size of the input schema file is 100 kB. If the input schema is provided, then input is always validated to fulfill the schema when an actor is being started (via API or from a run console at the Apify platform).

You can also use our visual input schema editor to guide you through creation of the INPUT_SCHEMA.json file.

Example

Imagine you are building a simple crawler whose inputs are an array of start URLs and a Javascript function that will be executed at each page the crawler visits. Then the input schema will look as follows:

{
    "title": "Cheerio Crawler input",
    "description": "To update crawler to another site you need to change startUrls and pageFunction options!",
    "type": "object",
    "schemaVersion": 1,
    "properties": {
        "startUrls": {
            "title": "Start URLs",
            "type": "array",
            "description": "URLs to start with",
            "prefill": [
                { "url": "http://example.com" },
                { "url": "http://example.com/some-path" }
            ],
            "editor": "requestListSources"
        },
        "pageFunction": {
            "title": "Page function",
            "type": "string",
            "description": "Function executed for each request",
            "prefill": "async () => {\n  return $('title').text();\n\n}",
            "editor": "javascript"
        }
    },
    "required": ["startUrls", "pageFunction"]
}

And generated the input UI will be:

Apify actor input schema example

If you switch the input to raw display using the blue toggle, then you will see the entered input stringified to a JSON format as it will be passed to the actor:

{
  "startUrls": [
    {
      "url": "http://example.com"
    },
    {
      "url": "http://example.com/some-path"
    }
  ],
  "pageFunction": "async () => {\n  return $('title').text();\n\n}"
}

Structure

The input schema is a JSON file named INPUT_SCHEMA.json, placed in the root directory of an actor with the following structure:

{
    "title": "Cheerio Crawler input",
    "type": "object",
    "schemaVersion": 1,
    "properties": { /* here is a place for the definition of input fields */ },
    "required": []
}

Property	Type	Required	Description
`title`	String	Yes	Any text describing your input schema.
`description`	String	No	Help text for the input that will be displayed above the UI fields.
`type`	String	Yes	This is fixed and must be set to string `object`.
`schemaVersion`	Integer	Yes	The version of the input schema specification against which your schema is written. Currently, only version `1` is out.
`properties`	Object	Yes	This is an object mapping each field key to its specification.
`required`	[String]	No	An array of field keys that are required.

Fields

Each field of your input is described under its key in inputSchema.properties object. The field might have integer, string, array, object or boolean type and its specification contains the following properties:

Property	Value	Required	Description
`type`	One of `string`, `array`, `object`, `boolean`, `integer`	Yes	Allowed type for the input value. Cannot be mixed.
`title`	String	Yes	Title of the field in UI.
`description`	String	Yes	Description of the field that will be displayed as help text in Actor input UI.
`default`	Must match `type` property.	No	Default value that will be used when no value is provided.
`prefill`	Must match `type` property.	No	Value that will be prefilled in the actor input interface. Only the `boolean` type doesn't support `prefill` property.
`example`	Must match `type` property.	No	Sample value of this field for the actor to be displayed when actor is published in Apify Store.
`sectionCaption`	String	No	If this property is set, then all fields following this field (this field included) will be separated into a collapsible section with the value set as its caption. The section ends at the last field or the next field which has `sectionCaption` property set.
`sectionDescription`	String	No	If the `sectionCaption` property is set, then you can use this property to provide additional description to the section. The description will be visible right under the caption when the section is open.

Additional properties

In addition to the properties listed above, most of the types support also additional properties defining, for example, the UI input editor.

String

Example of a code input:

{
    "title": "Page function",
    "type": "string",
    "description": "Function executed for each request",
    "editor": "javascript",
    "prefill": "async () => {\n  return $('title').text();\n\n}"
}

Rendered input:

Apify actor input schema page function

Example of country selection using a select input:

{
    "title": "Country",
    "type": "string",
    "description": "Select your country",
    "editor": "select",
    "default": "us",
    "enum": ["us", "de", "fr"],
    "enumTitles": ["USA", "Germany", "France"]
}

Rendered input:

Apify actor input schema - country input

Properties:

Property	Value	Required	Description
`editor`	One of `json`, `textfield`, `textarea`, `javascript`, `select`, `hidden`	Yes	Visual editor used for the input field.
`pattern`	String	No	Regular expression that will be used to validate the input.
`minLength`	Integer	No	Minimum length of the string.
`maxLength`	Integer	No	Maximum length of the string.
`enum`	[String]	Required if `editor` is `select`	Using this field, you can limit values to the given array of strings. Input will be displayed as select box.
`enumTitles`	[String]	No	Titles for the `enum` keys described.
`nullable`	Boolean	No	Specifies whether `null` is an allowed value.

Boolean

Beware that the boolean input type doesn't support the prefill property, since there is no way to display the prefilled value in the user interface.

Example options with group caption:

{
    "verboseLog": {
        "title": "Verbose log",
        "type": "boolean",
        "description": "Debug messages will be included in the log.",
        "default": true,
        "groupCaption": "Options",
        "groupDescription": "Various options for this actor"
    },
    "lightspeed": {
        "title": "Lightspeed",
        "type": "boolean",
        "description": "If checked then actors runs at a speed of light.",
        "default": true
    }
}

Rendered input:

Apify actor input schema options

Properties:

Property	Value	Required	Description
`editor`	One of `checkbox`, `hidden`	No	Visual editor used for the input field.
`groupCaption`	String	No	If you want to group multiple checkboxes together, add this option to the first of the group.
`groupDescription`	String	No	Description displayed as help text displayed of group title.
`nullable`	Boolean	No	Specifies whether null is an allowed value.

Integer

Example:

{
    "title": "Memory",
    "type": "integer",
    "description": "Select memory in megabytes",
    "default": 64,
    "maximum": 1024,
    "unit": "MB"
}

Rendered input:

Apify actor input schema memory

Properties:

Property	Value	Required	Description
`editor`	One of `number`, `hidden`	No	Visual editor used for input field.
`maximum`	Integer	No	Maximum allowed value.
`minimum`	Integer	No	Minimum allowed value.
`unit`	String	No	Unit displayed next to the field in UI, for example second, MB, etc.
`nullable`	Boolean	No	Specifies whether null is an allowed value.

Object

Example of proxy configuration:

{
    "title": "Proxy configuration",
    "type": "object",
    "description": "Select proxies to be used by your crawler.",
    "prefill": { "useApifyProxy": true },
    "editor": "proxy"
}

Rendered input:

Apify actor input schema proxy

The object where the proxy configuration is stored has the following structure:

{
    // Indicates whether Apify Proxy was selected.
    "useApifyProxy": Boolean,

    // Array of Apify Proxy groups. Is missing or null if Apify Proxy's
    // automatic mode was selected or if proxies are not used.
    "apifyProxyGroups": String[],

    // Array of custom proxy URLs. Is missing or null if custom proxies were not used.
    "proxyUrls": String[],
}

Example of a blackbox object:

{
    "title": "User object",
    "type": "object",
    "description": "Enter object representing user",
    "prefill": { "name": "John Doe", "email": "johndoe@gmail.com" },
    "editor": "json"
}

Rendered input:

Apify actor input schema user object

Properties:

Property	Value	Required	Description
`editor`	One of `json`, `proxy`, `hidden`	Yes	UI editor used for input.
`patternKey`	String	No	Regular expression that will be used to validate the keys of the object.
`patternValue`	String	No	Regular expression that will be used to validate the values of object.
`maxProperties`	Integer	No	Maximum number of properties the object can have.
`minProperties`	Integer	No	Minimum number of properties the object can have.
`nullable`	Boolean	No	Specifies whether null is an allowed value.

Array

Example of request list sources configuration:

{
    "title": "Start URLs",
    "type": "array",
    "description": "URLs to start with",
    "prefill": [{ "url": "http://example.com" }],
    "editor": "requestListSources"
}

Rendered input:

Apify actor input schema start urls array

Example of an array:

{
    "title": "Colors",
    "type": "array",
    "description": "Enter colors you know",
    "prefill": ["Red", "White"],
    "editor": "json"
}

Rendered input:

Apify actor input schema colors array

Properties:

Property	Value	Required	Description
`editor`	One of `json`, `requestListSources`, `pseudoUrls`, `keyValue`, `stringList`, `hidden`	Yes	UI editor used for input.
`placeholderKey`	String	No	Placeholder displayed for key field when no value is specified. Works only with `keyValue` editor.
`placeholderValue`	String	No	Placeholder displayed in value field when no value is provided. Works only with `keyValue` and `stringList` editors.
`patternKey`	String	No	Regular expression that will be used to validate the keys of items in the array. Works only with `keyValue` editor.
`patternValue`	String	No	Regular expression that will be used to validate the values of items in the array. Works only with `keyValue` and `stringList` editors.
`maxItems`	Integer	No	Maximum number of items the array can contain.
`minItems`	Integer	No	Minimum number of items the array can contain.
`uniqueItems`	Boolean	No	Specifies whether the array should contain only unique values.
`nullable`	Boolean	No	Specifies whether null is an allowed value.

Usage of this field is based on the selected editor:

requestListSources - value from this field can be used as input of RequestList class from Apify SDK.
pseudoUrls - is intended to be used with a combination of the PseudoUrl class and the Apify.utils.enqueueLinks() function from the Apify SDK.

Editor type requestListSources supports input in formats defined by the sources property of RequestListOptions.