How to make a Line chatbot with AWS Lambda

4 min readMay 25, 2024

Since I participated Hackathon held by AWS just one week ago, I want to practice how to use AWS services. This side project is just a practice to make a very simple Line chatbot (echo chatbot) using AWS Lambda. I will write another article to explain how to create an AI Line chatbot using AWS bedrock and AWS dynamoDB. Let’s get started.

The steps are following:

Create a Business Line account and create a Line official account
Open the webhook feature in Line
Copy the Channel access token and Channel secret from Line Official account, we will use it later.
Create AWS account
Create a Lambda function
Upload the required package as layers in AWS Lambda
Create API in Lambda (without entering API gateway)
Put API into Line webhook, and test it.

Since I am lazy, I will start writing from step 5. If you want to know how to create Line business account, you can see this link.

Also, don’t worry about price. AWS Lambda is free if the number of request events is lower than 1 million per month. It is very difficult for a side project.

Create a Lambda Function

When you get into the AWS console, please click the Lambda function to enter it, and then click Create Function.

After clicking, you can name your function whatever you want, and please change your runtime as Python 3.12. Everything else can stay as default, and press Create Function.

Put the following code into Code Source and press Deploy

from linebot.v3 import ( WebhookHandler ) 
from linebot.v3.messaging import ( Configuration, ApiClient, MessagingApi, TextMessage, ReplyMessageRequest ) 
from linebot.v3.exceptions import ( InvalidSignatureError ) 
from linebot.v3.webhooks import ( MessageEvent, TextMessageContent ) 
import os 
import json 

configuration = Configuration(access_token=os.environ['Channel_access_token']) 
handler = WebhookHandler(os.environ['Channel_secret']) 
def lambda_handler(event, context): 
  @handler.add(MessageEvent, message=TextMessageContent) 
  def handle_message(event): 
    with ApiClient(configuration) as api_client: 
      line_bot_api = MessagingApi(api_client) 
      line_bot_api.reply_message( ReplyMessageRequest( reply_token=event.reply_token, messages=[TextMessage(text=event.message.text)] ) ) 
    signature = event['headers']['x-line-signature'] 
    body = event['body'] 
    try: 
      handler.handle(body, signature) 
    except InvalidSignatureError: 
      return { 'statusCode': 502, 'body': json.dumps("Invalid signature. Please check your channel access token/channel secret.") } 
   return { 'statusCode': 200, 'body': json.dumps("OK") }

Upload Requirement Package as Layer and Set Environment Variables

First, please find Configuration the section and find Environment variables it in the sidebar. Press Add variable and set your Channel access token and Channel secret from your Line business account.

Next,pip install line-bot-sdk -t target_dir to download line SDK into your target directory, and zip it as a zip file.

Then, click Layers on the sidebar of the AWS Lambda page, and press Create Layers. You can name this layer whatever you want, select Upload a .zip file, and Upload your zip file mentioned above. Press Create at the bottom of this page, and copy the ARN code.

Finally, go to Functions at the sidebar of the Lambda page, and press the name of your function. You can see there is a bar under the logo of Lambda saying that Layers (0). Press it, and press Add a Layer. Press Specify an ARN and paste the ARN code into the bar under the page. Press Add, and the layer is done.

If you want to know more about Layers, please check this link