Create/Delete a SharePoint custom theme using PowerAutomate

In a modern SharePoint site you can create custom themes using PowerShell, REST API & CSOM. In this blogpost I will show you how to create themes using PowerAutomate. The following REST endpoints are available

There is an online Theme Generator tool that you can use to define new custom themes. At the time of writing this post, the endpoints are open to everybody & not just to the SharePoint tenant admins which seems to be quite buggy. Laura Kokkarinen has written a very detailed blog post about this topic. I’ve got the inspiration to write about this topic from John Liu who has recently recorded a video about this. Find screenshot from the Theme generator tool:

Once you have defined the theme from the tool, click on the Export theme button on the Right top corner of the tool to export the theme as a code block in JS, JSON & PowerShell. In this case, click JSON & Copy the generated block

{
  "themePrimary": "#50AFC6",
  "themeLighterAlt": "#f7fcfd",
  "themeLighter": "#def1f6",
  "themeLight": "#c3e6ee",
  "themeTertiary": "#8ecddd",
  "themeSecondary": "#61b8ce",
  "themeDarkAlt": "#489eb3",
  "themeDark": "#3c8597",
  "themeDarker": "#2d626f",
  "neutralLighterAlt": "#faf9f8",
  "neutralLighter": "#f3f2f1",
  "neutralLight": "#edebe9",
  "neutralQuaternaryAlt": "#e1dfdd",
  "neutralQuaternary": "#d0d0d0",
  "neutralTertiaryAlt": "#c8c6c4",
  "neutralTertiary": "#d9d9d9",
  "neutralSecondary": "#b3b3b3",
  "neutralPrimaryAlt": "#8f8f8f",
  "neutralPrimary": "gray",
  "neutralDark": "#616161",
  "black": "#474747",
  "white": "#ffffff"
}

Flow for Creating or adding the Theme to the tenant:

Let’s create an instant flow with trigger Manually trigger a flow to add a theme to the tenant. Add two Compose actions as shown below

The first compose action is the actual definition copied from the theme generator tool

{
  "palette" : 
JSON block copied from the Theme generator tool
}

The second compose action has the name of the theme & its stringified JSON from the output of the previous compose action. To convert the JSON to string add a string expression on the dynamic content pane

{
"name":"My first Custom theme created using FLOW", 
"themeJson": @{string(outputs('Compose_-_Custom_Theme_Pallete'))}
}

Now add the action Send an HTTP request to SharePoint with the following parameters

Site Address: https://domain.sharepoint.com/sites/sitename

Method: POST

URI: /_api/thememanager/AddTenantTheme

Headers:

Key: Accept

Value: application/json;odata.metadata=minimal

Body: Output of the Second compose action (Compose – Theme Name)

Now you are ready to test the flow. Once its successful you can apply the custom theme to the site

Click cog wheel on the site to select the theme by selecting the Change the look link

For deleting the theme, add the action Send a HTTP request to SharePoint with the following parameters

Site Address: https://domain.sharepoint.com/sites/sitename

Method: POST

URI: /_api/thememanager/DeleteTenantTheme

Headers:

Key: Accept

Value: application/json;odata.metadata=minimal

Body: { “name”:”the name of your custom theme” }

Summary: Hope you find this post useful & informational. Let me know if there is any comments or feedback below.