Lambda functions can be “triggered” by the following type of events:
Note: after creating a Lambda function the AWS Lambda wizard navigates to a page to define triggers (events that trigger Lambda functions) on the left hand side of the page you select your triggers. The list is below.
Add triggers
Click on a trigger from the list below to add it to your function.
API GatewayCloudWatch EventsCloudWatch LogsCodeCommitDynamoDBKinesisS3SNS
It is worth adding that some events are pushed to Lambda and other events are pulled (polled).
DynamoDB Streams and Kinesis are pull based, and all others are pushed to Lambda.
References: