Integrating your web app with Slack

Creating a Slack App

To integrate slack into your own webapp, a first step is to create a “Slack App”.

  1. First, decide which Slack Workspace you want to create an app in (e.g., or ucsb-cs-open-lab.slack.come, etc)
  2. Start at:
  3. Click “Create an App”
  4. You’ll be asked for the name of your app and the name of your slack workspace. Click create.
  5. You’ll be redirected to a page for your new Slack app. If you scroll down that page, you’ll see App Credentials, such as:
    • App ID
    • Client ID
    • Client Secret
    • Signing Secret
    • Verification Token

    There are also many other things you can do on that page to configure the app.

Creating an incoming webhook

On the page for your slack app, you’ll see on the left hand side, a place that says: “Incoming Webhooks”.

These allow you to get an endpoint that you can use to post messages to a particular channel on your workspace without additional authentication. The URL itself is the authentication (it is obscure enough to be not guessable).

To create one:

That URL should be treated like a “secret”, because anyone having the URL can post to your slack without additional authentication. To post, it is only necessary to send an HTTPS POST message containing JSON such as:

{"text": "message contents go here"}

For example, this Ruby Code (courtesy of ProbablyFaiz from this proof-of-concept repo

def send_slack_message
    https =, url.port)
    https.use_ssl = true
    body = "{'text':'" + params[:message] + "'}"
    response =, body)
    redirect_to root_path

That’s the “old school” way of doing it, if you want to use a low level HTTPS client. More likely, there will be some Slack API client for your programming language of choice.

For example: