Top AWS Lambda Interview Questions and Answers (2024)

In this post, questions from AWS Lambda Interviews will be answered for Experienced and Freshers. We're trying to share our experience and learn how to help you make progress in your career.

1. What is AWS Lambda?

2. What limitations apply to AWS Lambda function code?

3. What events can trigger an AWS Lambda function?

4. What can trigger an execution of the Lambda function?

5. What are the factors that decide how AWS Lambda is charged?

6. What's AWS Lambda's best language?

7. What are different ways to trigger Lambda?

Q: What is AWS Lambda?
Ans:

AWS Lambda is a serverless, event-based computing platform that Amazon offers as part of Amazon Web Services. It is a computing service which runs code to events and automatically manages the computing resources that this code requires. This was released in November 2014.

Q: What limitations apply to AWS Lambda function code?
Ans:

Lambda introduces very few limits on standard language and operating system operations. However, there are few disabled activities such as inbound network connections and trace calls (a debugger system), and traffic from TCP port 25 as an anti-spam measure. IP/TCP sockets support outbound connections.

Q: What events can trigger an AWS Lambda function?
Ans:

Lambda-based applications (also known as serverless applications) are composed of functions triggered by events. A standard serverless application consists of one or more functions triggered by events such as object uploads to Amazon S3, Amazon SNS notifications, or API actions.

Q: What can trigger an execution of the Lambda function?
Ans:

This is a list of services invoking asynchronous functioning of Lambda

• Amazon Simple Storage Service
• Amazon Simple Notification Service
• Amazon Simple Email Service
• AWS CloudFormation
• Amazon CloudWatch Logs
• Amazon CloudWatch Events
• AWS CodeCommit
• AWS Config

Q: What are the factors that decide how AWS Lambda is charged?
Ans:

You are charged based on the amount of time it takes for your code to execute is dependent on the number of requests for your functions and the duration. Lambda counts a request each time it begins executing in response to an event notification or invoke call, including test invokes from the console.

Q: What's AWS Lambda's best language?
Ans:

Node and Python are recognised as the leading Lambda language, but it's interested to dig deeper into each of the versions used and to obtain the exact number. Node 8.10 with 51.7% of functions using it is the obvious winner.

Q: What are different ways to trigger Lambda?
Ans:

There are Three Ways To Trigger Lambda.

1. API Gateway event

   These events are considered as standard events. It will trigger your lambda function, when somebody is calling an API Gateway For Lambda. Need to specify in the configuration to find which event type has been triggered, or serverless.yml if you are using the Serverless Framework.

2. S3 events

   When someone(s) modifies the contents of an S3 bucket, S3 events occur. Content modification can be done by creating, removing, or updating a file. You may decide what type of action the lambda function triggers when specifying an event, whether it creates, removes, or updates a file.

3. DynamoDB events

   When someone updates a record in a specific DynamoDB table, it will immediately publish all of these changes in a stream and it will also mean that the lambda will be triggered because there is data in the stream. There are two different ways in which Lambda is triggered when there are data in the stream. First, if there are certain data in the stream, i.e. a single update to the database at a certain time, the lambda will be executed only once.The second way that Lambda is triggered is to process a sequence of events together in the stream. This saves running time a lot, as streams are pretty fast.