Skip to content


Switch branches/tags

Name already in use

A tag already exists with the provided branch name. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. Are you sure you want to create this branch?


Failed to load latest commit information.
Latest commit message
Commit time

Slack Events API adapter for Python

The Slack Events Adapter is a Python-based solution to receive and parse events from Slack’s Events API. This library uses an event emitter framework to allow you to easily process Slack events by simply attaching functions to event listeners.

This adapter enhances and simplifies Slack's Events API by incorporating useful best practices, patterns, and opportunities to abstract out common tasks.

💡 We wrote a blog post which explains how the Events API can help you, why we built these tools, and how you can use them to build production-ready Slack apps.

⚠️ Important Notice

If you use this library for Events API handling, you may need to use threads for stable event acknowledgement. See #84 for details.

If you're looking for the best recommended library at this point, check Bolt for Python:

The framework covers not only Events API but also all the latest Slack Platform features.

🤖 Installation

pip install slackeventsapi

🤖 App Setup

Before you can use the Events API you must create a Slack App, and turn on Event Subscriptions.

💡 When you add the Request URL to your app's Event Subscription settings, Slack will send a request containing a challenge code to verify that your server is alive. This package handles that URL Verification event for you, so all you need to do is start the example app, start ngrok and configure your URL accordingly.

Once you have your Request URL verified, your app is ready to start receiving Team Events.

🔑 Your server will begin receiving Events from Slack's Events API as soon as a user has authorized your app.

🤖 Development workflow:

  1. Create a Slack app on
  2. Add a bot user for your app
  3. Start the example app on your Request URL endpoint
  4. Start ngrok and copy the HTTPS URL
  5. Add your Request URL and subscribe your app to events
  6. Go to your ngrok URL (e.g. and auth your app

🎉 Once your app has been authorized, you will begin receiving Slack Events

⚠️ Ngrok is a great tool for developing Slack apps, but we don't recommend using ngrok for production apps.

🤖 Usage

⚠️ Keep your app's credentials safe!

  • For development, keep them in virtualenv variables.
  • For production, use a secure data store.
  • Never post your app's credentials to github.

Create a Slack Event Adapter for receiving actions via the Events API

Using the built-in Flask server:

from slackeventsapi import SlackEventAdapter

slack_events_adapter = SlackEventAdapter(SLACK_SIGNING_SECRET, endpoint="/slack/events")

# Create an event listener for "reaction_added" events and print the emoji name
def reaction_added(event_data):
  emoji = event_data["event"]["reaction"]

# Start the server on port 3000

Using your existing Flask instance:

from flask import Flask
from slackeventsapi import SlackEventAdapter

# This `app` represents your existing Flask app
app = Flask(__name__)

# An example of one of your Flask app's routes
def hello():
  return "Hello there!"

# Bind the Events API route to your existing Flask app by passing the server
# instance as the last param, or with `server=app`.
slack_events_adapter = SlackEventAdapter(SLACK_SIGNING_SECRET, "/slack/events", app)

# Create an event listener for "reaction_added" events and print the emoji name
def reaction_added(event_data):
  emoji = event_data["event"]["reaction"]

# Start the server on port 3000
if __name__ == "__main__":

For a comprehensive list of available Slack Events and more information on Scopes, see

🤖 Example event listeners

See for usage examples. This example also utilizes the SlackClient Web API client.

🤔 Support

Need help? Join Slack Community and talk to us in #slack-api.

You can also create an Issue right here on GitHub.