Lambda Event Router

A TypeScript framework for routing AWS Lambda events. You define routers for the AWS services you care about - SQS, API Gateway, DynamoDB Streams, S3 and more - and the framework works out which router should handle each event.

This is useful when you want a single Lambda (or a set of Lambdas with shared code) to handle events from multiple sources. Instead of writing your own event detection logic, you declare filters and handlers and let the router do the matching.

import { LambdaRouter } from '@lambda-event-router/base'
import { apiGatewayRouter } from './api'
import { sqsRouter } from './sqs'
import { dynamoDBRouter } from './dynamo'
import { s3Router } from './s3'

const lambdaRouter = new LambdaRouter({
  routers: [apiGatewayRouter, sqsRouter, dynamoDBRouter, s3Router]
})

export const handler = lambdaRouter.handler()

Features

• Multi-source routing - Combine routers from different AWS services in a single Lambda handler
• Type-safe - Full TypeScript support with inferred types from schemas and filters for inline handlers
• Declarative filters - Route events by service-specific data - ARN, eventType, topic, bucket, event name, detail type and custom filter functions
• Native support for 29+ AWS services - Includes dedicated routers for SQS, SNS, EventBridge, DynamoDB Streams, S3, API Gateway, and more. Any service that emits Lambda events is supported out of the box.
• Works with any AWS service - Even services without native Lambda support can be integrated using CloudTrail and EventBridge using the EventBridgeRouter.
• Schema validation - Built-in validation for request bodies, message attributes, path params and more. Works with any Standard Schema library
• Well tested - Clear tests covering most code branches for each event type

This framework isn't the right fit in every situation. See When not to use it for more details.

Packages / Supported AWS services

Below is an overview of the packages and routers included. Each package can be installed individually.

For usage details, check the individual READMEs linked in the table.

Service	Feature / Event Source	Package	Router	Link
Amazon API Gateway	REST API	@lambda-event-router/apigateway	APIGatewayRouter	README
Amazon API Gateway	HTTP API	@lambda-event-router/apigateway	APIGatewayRouter	README
Amazon API Gateway	WebSocket	@lambda-event-router/apigateway	WebSocketRouter	README
Amazon API Gateway	Lambda Authorizer	@lambda-event-router/apigateway	LambdaAuthorizerRouter	README
Elastic Load Balancing	Application Load Balancer	@lambda-event-router/alb	ALBRouter	README
Amazon VPC Lattice	VPC Lattice	@lambda-event-router/vpclattice	VPCLatticeRouter	README
Amazon SQS	Queue	@lambda-event-router/sqs	SQSRouter	README
Amazon SNS	Topic notification	@lambda-event-router/sns	SNSRouter	README
Amazon DynamoDB	Streams	@lambda-event-router/dynamodb	DynamoDBRouter	README
Amazon Kinesis	Data Streams	@lambda-event-router/kinesis	KinesisRouter	README
Amazon Data Firehose	Transformation	@lambda-event-router/firehose	FirehoseRouter	README
Amazon MSK / Self-managed	Kafka	@lambda-event-router/kafka	KafkaRouter	README
Amazon MQ	ActiveMQ	@lambda-event-router/mq	ActiveMQRouter	README
Amazon MQ	RabbitMQ	@lambda-event-router/mq	RabbitMQRouter	README
Amazon DocumentDB	Change Streams	@lambda-event-router/documentdb	DocumentDBRouter	README
Amazon EventBridge	Rule	@lambda-event-router/eventbridge	EventBridgeRouter	README
Amazon EventBridge	Pipe	@lambda-event-router/eventbridge	EventBridgeRouter	README
Amazon EventBridge	Bus	@lambda-event-router/eventbridge	EventBridgeRouter	README
Amazon EventBridge	Scheduler	@lambda-event-router/base	EventRouter	README
Amazon S3	Object notification	@lambda-event-router/s3	S3Router	README
Amazon S3	Batch Operations	@lambda-event-router/s3	S3Router	README
Amazon CloudWatch	Logs subscription filter	@lambda-event-router/cloudwatch	CloudWatchLogsRouter	README
AWS Step Functions	Task	@lambda-event-router/stepfunctions	StepFunctionsRouter	README
AWS CodePipeline	Job	@lambda-event-router/codepipeline	CodePipelineRouter	README
Amazon Cognito	User Pool triggers	@lambda-event-router/cognito	CognitoRouter	README
AWS AppSync	Resolver	@lambda-event-router/appsync	AppSyncRouter	README
AWS AppSync	Authorizer	@lambda-event-router/appsync	AppSyncAuthorizerRouter	README
AWS AppSync	Events	@lambda-event-router/appsync	AppSyncEventsRouter	README
Amazon SES	Email receipt	@lambda-event-router/ses	SESRouter	README
Amazon Connect	Contact flow	@lambda-event-router/connect	ConnectRouter	README
Amazon Lex	Bot (v2)	@lambda-event-router/lex	LexRouter	README
AWS Secrets Manager	Rotation	@lambda-event-router/secretsmanager	SecretsManagerRouter	README
AWS Config	Custom Rule	@lambda-event-router/config	ConfigRouter	README
AWS Config	Scheduled Rule	@lambda-event-router/config	ConfigScheduledRouter	README
AWS CodeCommit	Repository trigger	@lambda-event-router/codecommit	CodeCommitRouter	README
AWS CloudFormation	Custom Resource	@lambda-event-router/cloudformation	CloudFormationRouter	README
AWS IoT Core	Rules Engine action	@lambda-event-router/iot	IoTRouter	README

Quick start

Install the base package and the service router you need:

npm install @lambda-event-router/[package]

For example, to install routers for apigateway and sqs

npm install @lambda-event-router/apigateway @lambda-event-router/sqs

Basic usage

Here's a quick look at how you define handlers. For the full details on each router, check their individual READMEs.

// main handler
import { LambdaRouter } from '@lambda-event-router/base'
import { apiRouter } from './api'
import { sqsRouter } from './sqs'

const lambdaRouter = new LambdaRouter({
  routers: [apiRouter, sqsRouter]
})

export const handler = lambdaRouter.handler()

// api.ts
import { createAPIGatewayRouter } from '@lambda-event-router/apigateway'

const apiRouter = createAPIGatewayRouter()

apiRouter.route({
  filter {
    method: 'POST'
    path: '/order/:id/'
  },
  handler: createOrder // Puts message on an SQS queue with a message attribute of ProcessOrder (string)
})

// sqs.ts
import { createSQSRouter } from '@lambda-event-router/sqs'
import { processOrder } from './order/process'
import { refundOrder } from './order/refund'

const sqsRouter = createSQSRouter()

sqsRouter.route({
  filter: {
    messageAttributes: {
      Type: ['ProcessOrder'],
    }
  },
  handler: processOrder
})

sqsRouter.route({
  filter: {
    messageAttributes: {
      Type: ['RefundOrder'],
    }
  },
  handler: refundOrder
})

Examples

See the examples directory for working examples covering every supported service.

There is also a full-examples directory with deployable code you can spin up on your own AWS environment with a few commands.

When not to use it

If your Lambda handles a single event source in a single way, you probably don't need this. Here are some cases where it isn't the right fit:

• Single event source with no filtering - Your Lambda receives events from one source and processes them all the same way. A plain handler function is simpler
• Single-purpose Lambdas - Your Lambda does exactly one thing. Routing and filtering add indirection with no upside
• HTTP-only Lambdas - Dedicated HTTP frameworks like Express, Hono and Fastify have richer ecosystems for middleware, auth and templating
• Performance-critical Lambdas with simple logic - The router iterates through registered routers via canHandleEvent checks and applies middleware chains. For ultra-simple Lambdas where every millisecond counts, a direct handler avoids this overhead
• One Lambda per event source - If you intentionally map one Lambda to one event source for isolated scaling, permissions or deployment, there's nothing to route between