Send Teams channel message aka proactive message using custom Teams bot and Power Automate – Part 1

Microsoft Teams connector in Power Automate has actions which can send a simple text message or Adaptive card as a flow bot in a Teams channel. Messages or cards are posted as the user who’s signed into the connector in the flow or by using the flow bot.

Messages can be posted on a Teams channel only if the signed in user or account of the connector is a member or an Owner of the Microsoft Team. Recently I had a requirement from my customer to post or broadcast messages on numerous Teams channels (> 1000). It is impossible per the limits for Microsoft Teams to have a dedicated service account as a member of all teams in scope. There is no graph API with application permission which can send a message in a channel. In this blog post, let us see how I have overcome the limitation of posting a message or card in multiple teams with the help of

  1. Custom Teams App with a Bot
  2. Installation of Teams App in Teams
  3. Bot connector REST API to post a Message or Adaptive Card aka proactive message

Custom Teams App with a Bot:

The teams in scope to receive the channel post or Adaptive card message should have a custom Teams app installed. The Teams app should have a Bot as its app features enabling the Microsoft team to receive the message. In this section, let us see how to create a Teams App with a Bot using the Developer Portal for Teams. Step 1: Login to the Teams Developer portal using your Microsoft 365 login ID and then Click + New app as shown below

Step 2: In the following screen for the Basic information of the app, enter the following mandatory information like Short name, App ID (Auto Generated), Short description, Long description, Developer or company name, Website (Valid HTTPS URL), Privacy policy url, Terms of use url. Once all of the above information is entered, click Save at the top left corner as shown below.

To apply a custom logo or an app icon for the Teams app, click Branding on the left navigation bar in the Teams developer portal as shown above.

Application (client) ID – Teams Activity Feed:

You can leave the Application (client) ID as blank. This section will be filled for custom Teams Activity Feed use case.

Step 3: On the left navigation, click App features > Bot

Step 4: Click Create a new bot which will take you to the Bot management portal. If you already have a bot where you are an Owner, it will be listed in the dropdown as shown below.

Step 5: In the Bot management, click + New Bot > Enter the name of the bot > Add

This step also registers an Azure AD app registration in the Azure AD Portal.

Step 6: Once the bot is added. In the Bot management portal url from the Developer Portal, copy the Bot ID and keep it handy to be used in the Power Automate cloud flow.

Step 7: Now click the registered bot in the above screen to Add a secret as shown below. As soon as the secret is generated, copy the value and keep it handy to be used in Power Automate cloud flow.

To change the logo of the Bot, login to this URL

Step 8: Go back to the created Teams app in the Developer Portal, in App features > Select the created bot > Set the scope to Team > Save

Installation of Teams App in Teams:

The Teams app is now configured with required features to send Teams channel conversation post. Download the App manifest package from the Developer Portal as shown below

Upload app in Microsoft Teams [Side Loading]:

Go through this Microsoft Documentation link to sideload the Teams App to your Teams client as a developer before publishing the package to the Teams Organization App catalog.

Go to the Teams Desktop Client > Apps > Manage your apps > Upload a custom app > Select the App manifest Zip package from above step > Add to a team > Select the Team to install the app > Setup a bot.

Find below the screenshot for your reference from Teams Desktop client

To validate the installation of the app, go to the Installed Team > Manage Team > Apps > You can find the installed app as shown below

Upload app in Microsoft Teams [Organization App Catalog]:

After the app is tested, the app can be deployed at scale once the app is available in the Teams Organization App catalog through Graph API. The pre-requisite to call the Graph API enpoint to install the app is the

  1. Teams ID (Group ID)
  2. Teams APP ID from the App catalog


In the next post I will cover how to use Bot Framework REST API in Power Automate Cloud Flow to send the Adaptive card message in a Teams Channel. If you are visiting my blog for the first time, please do look at my other blogposts.

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