🚀 Building a Scalable Two-Tier Backend with AWS Lambda, API Gateway, DynamoDB and Redis Caching

A practical, real-world serverless architecture using AWS services to build scalable CRUD APIs.

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📌 Project Overview

In this project, I built a two-tier backend on AWS using:

• API Gateway for request routing

• Lambda for serverless logic

• DynamoDB as a NoSQL database

• (Bonus) Redis caching (ElastiCache) documented for advanced performance

This project is part of my AWS Projects Portfolio on GitHub and focuses on building scalable, event-driven cloud backends that follow serverless best practices.

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🧠 What is a Two-Tier Backend?

A two-tier architecture separates:

• Tier 1 (Logic/Compute): AWS Lambda (or Fargate)

• Tier 2 (Storage): DynamoDB (or RDS)

The client talks to the API Gateway → Lambda processes the request → DynamoDB stores or retrieves the data.

This makes the architecture scalable, cost-efficient, and serverless by design.

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🛠️ AWS Services Used

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🔧 Features Implemented

• ✅ Create Item API

• ✅ Get Item by ID

• ✅ Update Item

• ✅ Delete Item

• ✅ RESTful endpoints using Lambda integrations

• 🧠 Documented Redis-based caching logic (for production setups)

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📐 Architecture Diagram

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📁 Project Structure

Two-Tier-Backend-With-Caching/
├── lambda/
│   ├── create_item.py
│   ├── get_item.py
│   ├── update_item.py
│   └── delete_item.py
├── architecture.png
└── README.md

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🔥 Sample API Flow

1. Client sends a POST request to /create-item

2. API Gateway routes to create_item Lambda

3. Lambda inserts data into DynamoDB

4. (Optional) Redis checks if data is cached before fetching from DB

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🧪 Test with Postman / Curl

curl -X POST https://your-api-id.execute-api.region.amazonaws.com/prod/create-item \
  -H "Content-Type: application/json" \
  -d '{"itemId": "123", "name": "Project X"}'

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💼 Business Impact

• Cost-efficient: Pay-per-request via Lambda

• Scalable: Auto-scales without worrying about servers

• Fast: Optional Redis layer boosts reads

• Modular: Swap DynamoDB with RDS if needed

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📚 Lessons Learned

• Learned how to configure Lambda-DynamoDB IAM policies

• Designed clean REST APIs using AWS API Gateway

• Understood when and how to add caching for reads

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🧠 Bonus: Redis Caching Flow (Documented)

Though not implemented in the free tier version, I’ve added docs on how to:

• Add Redis read-through cache logic

• Integrate ElastiCache Redis with Lambda securely

• Set TTL and cache eviction

Check it out on GitHub → redis.md

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🔗 GitHub Repository

📂 Two-Tier Backend with Caching – Source Code

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🙌 Final Thoughts

This is a solid blueprint for serverless backend APIs using AWS. If you're starting a backend SaaS, microservice, or internal tool—this pattern can serve as your foundation.

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✍️ Tags

#aws #lambda #api-gateway #dynamodb #serverless #devops #portfolio

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