Serverless Notes API

Overview

The Serverless Notes API is a REST API built on AWS that supports full CRUD operations for notes.
It uses Amazon API Gateway to expose HTTP endpoints, AWS Lambda to run backend logic, and Amazon DynamoDB to store note data.

Infrastructure is deployed using AWS SAM, demonstrating how to build and manage serverless applications with Infrastructure as Code.

Features

• Create notes
• Retrieve notes by ID
• Update note content
• Delete notes
• Fully serverless backend architecture

Architecture

Client → API Gateway → Lambda → DynamoDB

AWS Services Used

• AWS Lambda
• Amazon API Gateway
• Amazon DynamoDB
• AWS IAM
• AWS SAM
• Amazon CloudWatch

Architecture Explanation

The client sends an HTTP request to Amazon API Gateway, which routes the request to the appropriate AWS Lambda function based on the HTTP method and endpoint.

Each Lambda function handles a specific operation such as creating, retrieving, updating, or deleting a note. The functions interact with the DynamoDB Notes table to store and retrieve data.

Execution logs are automatically captured in Amazon CloudWatch Logs, which helps with monitoring and debugging the application.

Request Flow

1. The client sends a request to an API endpoint\
2. API Gateway routes the request to the appropriate Lambda function\
3. The Lambda function processes the request\
4. DynamoDB stores or retrieves the note data\
5. The API returns a JSON response to the client

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API Endpoints

Base URL

https://YOUR\_API\_ID.execute-api.YOUR\_REGION.amazonaws.com/STAGE

Example:

https://abc123.execute-api.us-east-1.amazonaws.com/Prod

Create a Note

POST /notes

Creates a new note.

Example:

curl -X POST "https://YOUR\_API\_ID.execute-api.YOUR\_REGION.amazonaws.com/STAGE/notes" -H "Content-Type: application/json" -d "{\"content\":\"My first cloud note\"}"

Retrieve a Note

GET /notes/{id}

Fetches a note using its ID.

Example:

curl "https://YOUR\_API\_ID.execute-api.YOUR\_REGION.amazonaws.com/STAGE/notes/YOUR\_NOTE\_ID"

Update a Note

PUT /notes/{id}

Updates the content of an existing note.

Example:

curl -X PUT "https://YOUR\_API\_ID.execute-api.YOUR\_REGION.amazonaws.com/STAGE/notes/YOUR\_NOTE\_ID" -H "Content-Type: application/json" -d "{\"content\":\"Updated note content\"}"

Delete a Note

DELETE /notes/{id}

Deletes a note by ID.

Example:

curl -X DELETE "https://YOUR\_API\_ID.execute-api.YOUR\_REGION.amazonaws.com/STAGE/notes/YOUR\_NOTE\_ID"

Deployment

Build the application:

sam build

Deploy the infrastructure:

sam deploy

Monitoring

Amazon CloudWatch Logs are used to monitor Lambda execution and troubleshoot API behavior during development and testing.

What I Learned

• How to build a serverless REST API using AWS services\
• How Lambda integrates with API Gateway to process HTTP requests\
• How DynamoDB stores and retrieves NoSQL data\
• How to deploy infrastructure using AWS SAM\
• How to debug and monitor serverless applications using CloudWatch

Architecture Diagram

AWS_serverless_API_architecture.jpg