Slack Dialog API

Slack's Dialog API lets apps open form-like popups inside Slack to collect structured input from users. Apps trigger a dialog (often from a slash command, message action, or interactive message) by calling dialog.open with a short-lived trigger_id, then present fields like text inputs, textareas, and select menus (including dynamic, server-powered options). When users submit or cancel, Slack sends a dialog_submission or dialog_cancellation payload to the app, which can validate inputs and send dialog_errors for inline feedback before completing the workflow. Dialogs are ephemeral to the user and well-suited for tasks like creating tickets, requesting PTO, or gathering parameters. Note: Slack now recommends using Block Kit modals via the Views API, which supersede legacy dialogs.