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Getting started with the Deno Slack SDK

Workflow apps require a paid plan

Join the Developer Program and provision a sandbox with access to all Slack features for free.

In the following guide, you'll install the Slack CLI and authorize it in your workspace. Then, you'll use the Slack CLI to scaffold a fully-functional workflow app and run it locally.

Don't have a workspace yet? You can get up and running by provisioning a sandbox with an associated workspace by following this guide. Come on back when you're ready!

Step 1: Install the Slack CLI​

Refer to these instructions to install the latest version of the Slack CLI. The instructions will guide you through installing the Slack CLI and all required dependencies. If you have VSCode installed, the VSCode Deno extension will be installed.

Step 2: Authorize the Slack CLI​

With the Slack CLI installed, authorize the Slack CLI in your workspace with the following command:

slack login

In your terminal window, you should see an authorization ticket in the form of a slash command, and a prompt to enter a challenge code:

$ slack login

📋 Run the following slash command in any Slack channel or DM
   This will open a modal with user permissions for you to approve
   Once approved, a challenge code will be generated in Slack

/slackauthticket ABC123defABC123defABC123defABC123defXYZ

? Enter challenge code

Copy the slash command and paste it into any Slack conversation in the workspace you will be developing in.

When you send the message containing the slash command, a modal will pop up, prompting you to grant certain permissions to the Slack CLI. Click the Confirm button in the modal to move to the next step.

A new modal with a challenge code will appear. Copy that challenge code, and paste it back into your terminal:

? Enter challenge code eXaMpLeCoDe

✅ You've successfully authenticated! 🎉
   Authorization data was saved to ~/.slack/credentials.json

💡 Get started by creating a new app with slack create my-app
   Explore the details of available commands with slack help

Verify that your Slack CLI is set up by running slack auth list in your terminal window:

$ slack auth list

myworkspace (Team ID: T123ABC456)
User ID: U123ABC456
Last updated: 2023-01-01 12:00:00 -07:00
Authorization Level: Workspace

You should see an entry for the workspace you just authorized. If you don't, get a new authorization ticket with slack login to try again.

You're now ready to begin building workflow apps! In the next step, we'll get started with a sample app.

Step 3: Create an app from a template​

info

Evaluate third-party apps Exercise caution when using third-party applications and automations (those outside of slack-samples). Review all source code created by third-parties before running slack create or slack deploy.

The create command is how you create a workflow app.

For this guide, we'll be creating a Slack app using the Deno Starter Template as a template:

slack create my-app --template https://github.com/slack-samples/deno-starter-template

The Slack CLI creates an app project folder and fills it with the sample app code. Once it has finished, cd into your new project directory:

cd my-app

Then continue to the next step.

Step 4: Run the app in local development mode​

While building your app, you can see your changes propagated to your workspace in real-time by running slack run within your app's directory.

slack run

When you execute slack run, you'll be asked to select a local environment:

? Choose a local environment
> Install to a new workspace or organization

Since you've not installed your app to any workspaces, select Install to a new workplace. Then select the workspace you authenticated in.

The Slack CLI will attempt to list any triggers, and in this case, will inform you there are no existing triggers installed for the app.

Triggers are what cause workflows to run. A link trigger generates a Shortcut URL which, when posted in a channel or added as a bookmark, becomes a link.

Triggers are created from trigger definition files. The Slack CLI will then look for any trigger definition files and prompt you to select one. In this case, there is only one trigger: sample_trigger.ts. Select it.

? Choose a trigger definition file:
> triggers/sample_trigger.ts
  Do not create a trigger

Once your app's trigger is created, you will see the following output:

⚡ Trigger successfully created!

  Sample trigger (local) Ft0123ABC456 (shortcut)
  Created: 2023-01-01 12:00:00 -07:00 (1 second ago)
  Collaborators:
    You! @You U123ABC456DE
  Can be found and used by:
    everyone in the workspace
  https://slack.com/shortcuts/Ft0123ABC456/XYZ123

The Slack CLI will also start a local development server, syncing changes to your workspace's development version of your app. You'll know your local development server is up and running when your terminal window tells you it's Connected, awaiting events.

Step 5: Use your app​

Grab the Shortcut URL you generated in the previous step and paste it in a public channel in your workspace. You will see the shortcut unfurl with a "Start Workflow" button. Click the button to execute the shortcut.

In the modal that appears, select a channel, and enter a message. When you click the "Send message" button, you should see your message appear in the channel you specified.

When you want to turn off the local development server, use Ctrl+c in the command prompt.

Onward​

At this point your Slack CLI is fully authorized and ready to create new projects. It's time to choose the next path of adventure.

We have curated a collection of sample apps. Many have tutorials. All highlight features of workflow apps. Learn how to:

Each tutorial will expose you to many aspects of the workflow automations. If you'd rather explore the documentation on your own, here are a few places to start. You can learn how to: