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Create a Slack app and authenticate with Postman

By John Agan

Published: September, 2017


This step-by-step guide will walk you through setting up a Slack App and then introduce you to Slack's OAuth authentication flow using an indispensable tool, Postman.


Getting Started

Creating a Slack App can be initiated by navigating directly to the Create App page.

Creating your app

Create Slack App

Fill out all the required fields. Notice there is a workspace selector. This is because every Slack must be associated to a workspace. This is where the App will live, but it does not mean users of the App will have access to that workspace.

If you're following along with Postman, make sure you use Postman's redirect URI: https://www.getpostman.com/oauth2/callback

OAuth Information

From the left navigation menu, click OAuth & Permissions to access the OAuth information. To authenticate into the App, you'll need the OAuth Client ID and Client Secret. For this tutorial, we will copy this information into Postman.




Now that we have a Slack App to authorize against, we will setup an OAuth 2.0 client. In this tutorial, we will use Postman's Authorization to walk through the flow.


In Postman's Authorization menu, select OAuth 2.0 for the type

Postman configuration

Get Token

Once OAuth 2.0 is selected as the type, click the Get New Access Token button to open the OAuth configuration modal.

Get that access token


Here we will setup the OAuth client. We'll pull information from multiple sources to complete this form. Find more information on Slack's OAuth flow in the docs.

  • Auth URL: https://slack.com/oauth/authorize
  • Access Token URL: https://slack.com/api/oauth.access
  • Client ID: Copy the Client ID value from Slack's OAuth Information page
  • Client Secret: Copy the Client Secret value from Slack's OAuth Information page
  • Scope: A space-separated list of OAuth scopes. A complete list of scopes are here.



If you set everything up correctly and pressed Request Token, you should see a familiar Slack authorization window. Select the team you would like to authorize and validate your scopes match what's presented.



After you click Authorize, Slack will return Postman a payload that is saved for future use. You can inspect the payload and find the details of that authorization.

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