Schedules a message to be sent to a channel.

Required Params

• channel - Channel, private group, or DM channel to send message to. Can be an encoded ID, or a name. ex: C1234567890
• post_at - Unix EPOCH timestamp of time in future to send the message. ex: 299876400

Optional Params

• as_user - Pass true to post the message as the authed user, instead of as a bot. Defaults to false. See chat.postMessage. ex: true
• attachments - A JSON-based array of structured attachments, presented as a URL-encoded string. ex: [{"pretext": "pre-hello", "text": "text-world"}]
• blocks - A JSON-based array of structured blocks, presented as a URL-encoded string. ex: [{"type": "section", "text": {"type": "plain_text", "text": "Hello world"}}]
• link_names - Find and link channel names and usernames. ex: true
• parse - Change how messages are treated. Defaults to none. See chat.postMessage. ex: full
• reply_broadcast - Used in conjunction with thread_ts and indicates whether reply should be made visible to everyone in the channel or conversation. Defaults to false. ex: true
• thread_ts - Provide another message's ts value to make this message a reply. Avoid using a reply's ts value; use its parent instead. ex: 1234567890.123456
• unfurl_links - Pass true to enable unfurling of primarily text-based content. ex: true
• unfurl_media - Pass false to disable unfurling of media content. ex: false

Errors the API can return:

• account_inactive - Authentication token is for a deleted user or workspace.
• channel_not_found - Value passed for channel was invalid.
• ekm_access_denied - Administrators have suspended the ability to post a message.
• fatal_error - The server could not complete your operation(s) without encountering a catastrophic error. It's possible some aspect of the operation succeeded before the error was raised.
• invalid_arg_name - The method was passed an argument whose name falls outside the bounds of accepted or expected values. This includes very long names and names with non-alphanumeric characters other than _. If you get this error, it is typically an indication that you have made a very malformed API call.
• invalid_arguments - The method was called with invalid arguments.
• invalid_auth - Some aspect of authentication cannot be validated. Either the provided token is invalid or the request originates from an IP address disallowed from making the request.
• invalid_charset - The method was called via a POST request, but the charset specified in the Content-Type header was invalid. Valid charset names are: utf-8 iso-8859-1.
• invalid_form_data - The method was called via a POST request with Content-Type application/x-www-form-urlencoded or multipart/form-data, but the form data was either missing or syntactically invalid.
• invalid_post_type - The method was called via a POST request, but the specified Content-Type was invalid. Valid types are: application/json application/x-www-form-urlencoded multipart/form-data text/plain.
• invalid_time - value passed for post_time was invalid.
• is_archived - Channel has been archived.
• missing_post_type - The method was called via a POST request and included a data payload, but the request did not include a Content-Type header.
• missing_scope - The token used is not granted the specific scope permissions required to complete this request.
• msg_too_long - Message text is too long
• no_permission - The workspace token used in this request does not have the permissions necessary to complete the request. Make sure your app is a member of the conversation it's attempting to post a message to.
• no_text - No message text provided
• not_authed - No authentication token provided.
• not_in_channel - Cannot post user messages to a channel they are not in.
• org_login_required - The workspace is undergoing an enterprise migration and will not be available until migration is complete.
• rate_limited - Application has posted too many messages, read the Rate Limit documentation for more information
• request_timeout - The method was called via a POST request, but the POST data was either missing or truncated.
• restricted_action - A workspace preference prevents the authenticated user from posting.
• restricted_action_non_threadable_channel - Cannot post thread replies into a non_threadable channel.
• restricted_action_read_only_channel - Cannot post any message into a read-only channel.
• restricted_action_thread_only_channel - Cannot post top-level messages into a thread-only channel.
• team_added_to_org - The workspace associated with your request is currently undergoing migration to an Enterprise Organization. Web API and other platform operations will be intermittently unavailable until the transition is complete.
• time_in_past - value passed for post_time was in the past.
• time_too_far - value passed for post_time was too far into the future.
• token_revoked - Authentication token is for a deleted user or workspace or the app has been removed.
• too_many_attachments - Too many attachments were provided with this message. A maximum of 100 attachments are allowed on a message.