Send & Post Message to Slack using API

 import logging
from typing import Optional

import uvicorn
from fastapi import FastAPI
from pydantic import BaseModel
from slack_sdk import WebClient
from slack_sdk.errors import SlackApiError

logger = logging.getLogger(__name__)

app = FastAPI()

# TODO: Replace with your Slack API token
slack_client = WebClient(token=SLACK_API_TOKEN)

class SlackMessage(BaseModel):
    channel: str
    text: str
    thread_ts: Optional[str] = None

About this template

A Rest API that sends personal messages to Slack, supporting both direct private messages to user and posting messages in threads.

Introduction to the Slack Message Sender Template

Welcome to the Slack Message Sender Template! This template is designed to help you quickly set up a REST API that can send messages to Slack channels or direct messages, and even post messages in threads. Whether you're looking to integrate Slack notifications into your workflow or create a bot that can interact with your team on Slack, this template will get you started without the need for deep technical knowledge.

Getting Started

To begin using this template, simply click on "Start with this Template" on the Lazy platform. This will pre-populate the code in the Lazy Builder interface, so you won't need to copy, paste, or delete any code manually.

Initial Setup

Before you can start sending messages to Slack, you'll need to set up a Slack API token. This token allows your application to authenticate with Slack and send messages on your behalf.

  1. Go to the Slack API website and create a new app.
  2. From the 'OAuth & Permissions' page, add the necessary scopes to send messages (e.g., 'chat:write').
  3. Install the app to your workspace and copy the OAuth Access Token provided.

Once you have your Slack API token, you'll need to add it to your Lazy app as an environment secret:

  1. Go to the Environment Secrets tab within the Lazy Builder.
  2. Create a new secret with the name 'SLACK_API_TOKEN' and paste your Slack API token as the value.

Test: Pressing the Test Button

With your Slack API token set up as an environment secret, you're ready to test the application. Press the "Test" button on the Lazy platform. This will deploy your app and launch the Lazy CLI.

Using the App

After pressing the "Test" button, Lazy will provide you with a dedicated server link to use the API. If you're using FastAPI, you'll also receive a link to the API documentation, which will help you understand the available endpoints and how to interact with them.

To send a message using the API, you'll need to make a POST request to the "/send_slack_message" endpoint with a JSON payload containing the 'channel', 'text', and optionally 'thread_ts' if you want to post in a thread. Here's a sample request:

  "channel": "C1234567890",
  "text": "Hello, world!",
  "thread_ts": "1234567890.123456"

And here's what a sample response might look like:

  "status": "success",
  "data": {
    "ok": true,
    "channel": "C1234567890",
    "ts": "1234567890.123456",
    "message": {
      "text": "Hello, world!"

Integrating the App

If you want to integrate this Slack messaging functionality into another service or frontend, you can use the server link provided by Lazy to make HTTP requests to the API. Ensure that you handle the authentication by including the Slack API token in your environment secrets and that you format your requests according to the Slack API documentation.

For example, if you're building a web dashboard that triggers Slack notifications, you would add the server link as the endpoint in your dashboard's backend code, making sure to send a POST request with the correct JSON payload to send messages.

By following these steps, you can seamlessly integrate Slack messaging capabilities into your applications using the Lazy platform.

Last published
May 18, 2024

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Send & Post Message to Slack using API