This is reference content about building functions and workflows. Learn more if you're not yet familiar with this new Slack platform paradigm.


Updates a canvas


Schema ID


Schema reference


Input parameters

Required parameters
How do you want to update? Options are append, prepend, or replace. Default is prepend.
Optional parameters
Type of update. Options are standalone or channel_canvas. Default is standalone.
Select a channel in cases when canvas_update_type is set to channel_canvas.
Select a canvas in cases when canvas_update_type is set to standalone.
Choose which section to update

Output parameters

Required parameters
Canvas link

Usage guide

This function updates the content of a canvas. Either canvas_id or channel_id must be provided, but not both. Which one is needed is based on the canvas_update_type. If the canvas_update_type is set to standalone, then a canvas_id should be provided. If canvas_update_type is set to channel_canvas, then a channel_id should be provided. The default value of canvas_update_type is standalone.

The app using this function will need the following App Home features set in the app manifest file:

features: {
  appHome: {
    messagesTabEnabled: true,
    messagesTabReadOnlyEnabled: false,

For information about the expanded_rich_text type that you can use to update your canvases, refer to expanded_rich_text.

Example workflow step:

const updateCanvasStep = ExampleWorkflow.addStep(
    action: "append",
    content: { inputs.content },
    canvas_update_type: "standalone",
    canvas_id: "CAN1234ABC"