Text inputs
Single-line and multi-line text fields, plus email, URL and number variants, for collecting free text in a modal or Home tab.
plain_text_input collects free text. Slack also ships three constrained variants that render the
same control with a different keyboard and, for email and URL, a small leading icon:
email_text_input, url_text_input and number_input. All four are input-block-only elements:
they don’t appear in an actions block or as a section accessory.
New task
Fields
type"plain_text_input" | "email_text_input" | "url_text_input" | "number_input"
Which variant to render. All four share the fields below.
"plain_text_input" | "email_text_input" | "url_text_input" | "number_input"action_id?string
Identifies this action in the interaction payload and as the key in `state.values`. Maximum length is 255 characters.
stringinitial_value?string
The value shown when the surface loads.
stringplaceholder?PlainTextElement
Grey placeholder text shown when the field is empty. Maximum length is 150 characters.
PlainTextElementmultiline?boolean
`plain_text_input` only. Renders a resizable textarea instead of a single-line field.
booleanfalsemin_length?number
`plain_text_input` only. Minimum number of characters required on submit. Maximum value is 3000.
numbermax_length?number
`plain_text_input` only. Maximum number of characters allowed.
numberis_decimal_allowed?boolean
`number_input` only. Allows a decimal point when `true`; otherwise only whole numbers can be typed. Required for this variant.
booleanmin_value?string
`number_input` only. The smallest value allowed; cannot be greater than `max_value`.
stringmax_value?string
`number_input` only. The largest value allowed; cannot be less than `min_value`.
stringdispatch_action_config?DispatchActionConfig
Configures which keystrokes fire a `block_actions` payload while typing. See Dispatching actions below.
DispatchActionConfigfocus_on_load?boolean
Focuses this field when the surface loads. Only one element per view can set this.
booleanfalseExamples
Single line vs. multiline
Setting multiline: true swaps the single-line field for a textarea that grows with the content.
Pressing Enter inside a multiline field inserts a newline instead of submitting.
Email, URL and number variants
email_text_input and url_text_input show a small envelope or link icon inside the field.
number_input restricts what can be typed to digits (and, with is_decimal_allowed: true, a
single decimal point), Slack rejects the keystroke rather than showing it and clearing it.
Dispatching actions as you type
By default, an input block’s element only reports its value into state.values, which your app
reads when the surface is submitted. Typing doesn’t fire an action. Set the block’s
dispatch_action: true and, optionally, the element’s dispatch_action_config to get a live
block_actions payload while the person types:
trigger_actions_on accepts on_enter_pressed (the default) and on_character_entered. With the
default, single-line fields also pick up a “Press ‘enter’ to submit” hint automatically, unless the
block already has its own hint. Multiline fields never show it, since Enter inserts a newline
there instead of submitting.
Initial value
The Website field above starts pre-filled with https://example.com via initial_value. Slack
reports the initial value into state.values as soon as the surface loads, before any typing.
Interactivity
With dispatch_action set, every trigger calls onAction with the current text as value:
{
"type": "plain_text_input",
"action_id": "search_input",
"block_id": "search",
"action_ts": "1706000000.000100",
"value": "rel"
}Reading the value
Every keystroke (and the initial value, if any) is written to state.values in Slack’s
{ type, value } shape, keyed by the element’s variant type:
{
"email": {
"email_input": { "type": "email_text_input", "value": "name@example.com" }
}
}