Use aws-lambda types, it have types for most of the events.

Example handlers:

import { SQSHandler, SNSHandler, APIGatewayProxyHandler } from 'aws-lambda';

export const sqsHandler: SQSHandler = async (event, context) => {
  
}

export const snsHandler: SNSHandler = async (event, context) => {
}

export const apiV2Handler: APIGatewayProxyHandler = async (event, context) => {
  return {
    body: 'Response body',
    statusCode: 200
  }
}

The aws-sdk does not contain the types for lambda. So you will need both aws-sdk and @types/aws-lambda unfortunately. Also I would suggest to declare the @types/aws-lambda in the devDependencies of your package.json.

import * as AWS from "aws-sdk";
import { Context } from "aws-lambda";

module.exports.hello = async (event:any, context:Context) => {
  // eg. if you need a DynamoDB client
  // const docClient: AWS.DynamoDB.DocumentClient = new AWS.DynamoDB.DocumentClient({region: 'ap-southeast-2'});
  return {
    statusCode: 200,
    body: JSON.stringify({
      message: 'function executed successfully!',
      input: event,
    }),
  };
};

The @types/aws-lambda package provides types for using TypeScript inside of an AWS Lambda function. For AWS Lambda functions invoked using API Gateway's Lambda Proxy integration type take the following steps:

Install the package

$ yarn add --dev @types/aws-lambda

Or if you prefer npm:

$ npm i --save-dev @types/aws-lambda

Then in your handler file:

import { APIGatewayProxyEvent, Context, APIGatewayProxyResult } from "aws-lambda"

export async function hello (event: APIGatewayProxyEvent, context: Context): Promise<APIGatewayProxyResult> {
  return {
    statusCode: 200,
    body: JSON.stringify({
      message: 'Hello world',
      input: event,
    })
  }
}