AWS Lambda · AsyncAPI Specification

AWS Lambda Event Triggers

Version 2015-03-31

AWS Lambda integrates with other AWS services to invoke functions in response to events. Lambda functions can be triggered by event sources including Amazon S3, Amazon DynamoDB Streams, Amazon Kinesis Data Streams, Amazon SQS, Amazon SNS, Amazon API Gateway, Amazon EventBridge, Amazon CloudWatch Events, Amazon Cognito, and many more. Event sources send event data as JSON payloads that Lambda passes to the function handler. Events are processed synchronously (push model), asynchronously (event model), or by Lambda polling a stream or queue (poll model).

View Spec View on GitHub AsyncAPIWebhooksEvents

Channels

s3/event

subscribe onS3Event

Receive S3 object event notifications

Amazon S3 sends event notifications to Lambda when objects are created, modified, or deleted in a bucket. S3 invokes your function asynchronously with an event that contains details about the object. You configure notifications on the S3 bucket to specify which events trigger the function.

dynamodb/stream

subscribe onDynamoDBStreamRecord

Receive DynamoDB Streams records

Amazon DynamoDB Streams captures a time-ordered sequence of item-level modifications in a DynamoDB table. Lambda polls the stream and invokes your function synchronously with a batch of stream records. You create an event source mapping to connect the stream to your function.

kinesis/stream

subscribe onKinesisRecord

Receive Kinesis Data Streams records

Amazon Kinesis Data Streams captures real-time data at scale. Lambda polls the Kinesis stream and invokes your function with a batch of records from one or more shards. You create an event source mapping to connect the stream to your function.

sqs/message

subscribe onSQSMessage

Receive SQS queue messages

Amazon SQS queues messages for asynchronous processing. Lambda polls the queue and invokes your function with a batch of messages. When the function successfully processes a batch, Lambda deletes the messages from the queue. Supports both standard and FIFO queues.

sns/notification

subscribe onSNSNotification

Receive SNS topic notifications

Amazon SNS delivers notifications to Lambda functions subscribed to an SNS topic. When a message is published to the topic, SNS invokes your function asynchronously with the message payload. Supports standard topics for fanout to multiple subscribers.

apigateway/request

subscribe onAPIGatewayRequest

Receive API Gateway HTTP requests

Amazon API Gateway invokes Lambda functions in response to HTTP API requests. API Gateway passes the request details as an event to the function and returns the function response to the caller. Supports REST APIs (v1 payload format) and HTTP APIs (v2 payload format).

eventbridge/event

subscribe onEventBridgeEvent

Receive EventBridge events

Amazon EventBridge delivers events from AWS services, custom applications, and SaaS partners to Lambda functions. EventBridge rules match incoming events and route them to target functions. You create rules that match event patterns and specify the Lambda function as a target.

cloudwatch/scheduledevent

subscribe onScheduledEvent

Receive scheduled invocations

Amazon EventBridge Scheduler (formerly CloudWatch Events scheduled rules) invokes Lambda functions on a schedule. You define a schedule expression using a rate or cron expression, and EventBridge invokes the function at the specified intervals.

cognito/trigger

subscribe onCognitoTrigger

Receive Cognito user pool trigger events

Amazon Cognito invokes Lambda functions as triggers during user pool operations such as sign-up, authentication, and token generation. The function can modify the authentication flow, validate data, or add custom claims.

cloudwatch/alarm

subscribe onCloudWatchAlarm

Receive CloudWatch alarm state changes

Amazon CloudWatch can invoke Lambda functions as alarm actions when a metric alarm changes state. The function receives details about the alarm state change.

cloudwatch/logs

subscribe onCloudWatchLogsEvent

Receive CloudWatch Logs subscription filter events

Amazon CloudWatch Logs can invoke a Lambda function when a subscription filter matches log events. The log data is delivered as a batch of log events compressed with gzip and base64-encoded.

Messages

✉

S3Event

Amazon S3 Event

S3 object event notification delivered to Lambda

✉

DynamoDBStreamEvent

Amazon DynamoDB Stream Event

Batch of DynamoDB Streams records delivered to Lambda

✉

KinesisEvent

Amazon Kinesis Event

Batch of Kinesis Data Streams records delivered to Lambda

✉

SQSEvent

Amazon SQS Event

Batch of SQS messages delivered to Lambda

✉

SNSEvent

Amazon SNS Event

SNS notification delivered to Lambda

✉

APIGatewayProxyEvent

API Gateway REST API Proxy Event (v1)

HTTP request from API Gateway REST API

✉

APIGatewayV2ProxyEvent

API Gateway HTTP API Proxy Event (v2)

HTTP request from API Gateway HTTP API

✉

EventBridgeEvent

Amazon EventBridge Event

Event from EventBridge event bus

✉

ScheduledEvent

Scheduled Event

Scheduled invocation from EventBridge Scheduler

✉

CognitoEvent

Amazon Cognito User Pool Trigger Event

Cognito user pool trigger event

✉

CloudWatchAlarmEvent

Amazon CloudWatch Alarm Event

CloudWatch alarm state change event

✉

CloudWatchLogsEvent

Amazon CloudWatch Logs Event

CloudWatch Logs subscription filter event

Servers

https

lambdaRuntime https://lambda.{region}.amazonaws.com

AWS Lambda service endpoint. Event sources deliver events to Lambda which invokes the configured function. The function receives the event payload as the first argument to the handler.